# IGaging DRO EMI Problem



## kcoffield (Dec 19, 2020)

I just finished a restoration of an old family lathe and added many upgrades. Among them was a three-phase motor with VFD and two iGaging Absolute DROs. The build thread is here.








						New Caretaker of Two 12” Craftsman Lathes
					

Hi all, first post here. I’m the new caretaker of two 12” Craftsman lathes, one with a 42” bed and the other 54”. Though they recently came into my possession they are well known to me. The 42 is model 101.07403 number SN 16014 and the 54 is model 101.07403 SN 22500. The only place I’ve found...




					www.hobby-machinist.com
				



I can be pretty handy with mechanical things but electronics is definitely not one of them…..as I’m sure I’m about to convince you. The following is a bit windy, but just trying to efficiently converge on a solution.

I used a small chain drag cable carrier for the DRO install to protect the cables. Here is a direct link to the DRO install portion of the thread.








						New Caretaker of Two 12” Craftsman Lathes
					

The 2-Step countershaft pulley has a chip out of the side of the larger groove but it should be OK to use. And the motor pulley is on the shaft of what appears to be a permag DC motor. All of the lathes in the bunch that Lon bought had DC motors, as the lathes were used for large coil and...




					www.hobby-machinist.com
				



Unfortunately, that consumed most of the available DRO cable length, so I figured I’d just buy a couple cable extenders to remedy that. The DRO control cable connections are Micro USB, and the power ports are 3.5mm x 1.35mm barrel jacks and type A USB on the other end that plug into the power supply which is a cheap wall wart. I built a little panel to remotely mount the VFD controls and did same to mount the DRO displays. The VFD and some components are located in a built-in enclosure on the back splash. I also read the iGaging DROs are fond of eating batteries so I installed a cheap power supply and power cables. The DRO cables are routed through the electrical enclosure where the VFD resides and the added DRO power cables originate from there. Here’s a couple of pictures of the lay out.








I installed everything with the cable extensions routed as planned, powered up the DROs and they worked just fine……until I turned on the VFD. Then the DROs went crazy. The motor does not have to be running, just the VFD powered up. Upon a little investigation, I may have both a conducted and radiated emission problem.

There is still enough length of the factory iGaging control cables to reach the displays which can be moved and attached anywhere, but not routed in an acceptable manner. So suspecting the cable extensions weren’t adequately shielded, I eliminated the cable extensions…….and DROs still go bonkers when I power up the VFD. I disconnected the power cables and let the DROs revert to battery and problem solved. The extension cables are also routed on top of a 24” LED light which is another potential source of interference, but it doesn’t seem to matter whether that is on or off. I have not pulled the DRO extension cables out to see if rerouting these cables alone will solve the problem but I doubt it. I did have a couple other power cables so I pulled the power supply, plugged it into another 120vac circuit via extension cord, and with the power cables at least 3-4ft from the VFD, the displays still go off the charts when I attach the power supply, but are fine on battery.

_So I’m looking for ideas to solve the problem. I sure would like to be able to use my present cable routing, but looking back, if one was trying to create an EMI problem, my scheme looks like a pretty sure way to do it._

I have read several other threads on iGaging noise susceptibility here on the forum, with a motor controller being the noise source. One was solved by a applying a capacitor across the power leads. I’ve inquired in that thread.

Since the factory control cables don’t seem to have a problem, *do you think there is there any chance that I could just make a custom cable with good shielding, and the bypass cap across the power leads, and use the same cable routing? *Or am I fighting a losing battle with proximity to the VFD?

A couple other tidbits, the iGaging absolute scales are stainless steel, and I believe they are grounded through mounting to the lathe, but I need to double check that because the lathe could be isolated by painted surfaces. All the metal surfaces on the cabinet, back splash, and lathe (tbc) are grounded. The 120 vac power source for everything is connected at a common node in the electrical enclosure….no filtering.

The small regulated 12 vdc power supply in the enclosure provides power for the tachometer. The tach has a magnetic sensor/pick-up located in the lower cabinet and its display and electronics are in the remote VFD panel. There are unshielded multiconductor 18 awg cables to the cabinet and remote panel routed through the electrical enclosure. The tach is completely unaffected and operates normally in all conditions. They are Amazon cheapies. I think the PS was $6 and the tach was $12.

The electrical enclosure looks pretty busy but it’s really only the VFD, and a couple small power supplies….the rest is just connectors and cabling.

*Opinions/suggestions welcome.*

Best,
Kelly


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## Winegrower (Dec 19, 2020)

Revert to battery operation.   I had these same readouts, maybe I replaced batteries every 6 months.


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## pontiac428 (Dec 19, 2020)

You can use shielded cable with a drain wire, or you can use ferrite beads.  They work.


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## homebrewed (Dec 19, 2020)

Some iGaging users have found that they needed to electrically isolate the scales from the machine.  To do that it's necessary to make replacement mounting blocks out of plastic.  You mentioned the fact that all the machine surfaces are painted, but the screw holes aren't, eh?

Having said that, I tried it on my mill and it didn't work for me.  So try it on one axis first before spending more time on a potentially fruitless venture.

I put shield braid over the DRO cables:  no improvement.  As mentioned, insulated mounting blocks:  no improvement.  I put 1uf caps across Vcc and Gnd inside the read heads:  that helped but did not eliminate the problem, at least not on my DROs with aluminum scales.  However, I later got a pair of DROs for my lathe and they have stainless-steel rules -- and adding capacitors alone did the trick for them.  So if I were you I'd just open up the read heads and solder in some capacitors across Vcc and Gnd.  1uF caps worked for me.  And since there's only 3.3V there you don't have to worry about the voltage rating of the capacitors.  

If you use electrolytics make sure the + side of the capacitors connect to Vcc.  Also there's limited room inside the case so make sure what you get will fit inside.  A 100uF capacitor probably won't (and is overkill anyway) .


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## kcoffield (Dec 19, 2020)

Thanks for the replies.



pontiac428 said:


> You can use shielded cable with a drain wire, or you can use ferrite beads. They work.


It'd be great if something as simple as the clip on ferrite bead would work. They're inexpensive. I see there a number of different materials for different frequency ranges. Any advice on that? I see those in Digikey. 

How about high quality shielded USB cable? Micro B male to Micro B female seems hard to find except in the cheap consumer stuff. I need 5-6 ft of extension. I have braided sleeving I could pull over everything but Homebrewed didn't seem to have any success with it. I have not seen cabling other than the consumer stuff and there's a lot micro B extension cables that are just power cable and not all 5 pins active. Any recommended online sources for cables or ferrite cores?



homebrewed said:


> 1uF caps worked for me. And since there's only 3.3V there you don't have to worry about the voltage rating of the capacitors. If you use electrolytics make sure the + side of the capacitors connect to Vcc. Also there's limited room inside the case so make sure what you get will fit inside.


Could the cap be applied anywhere along the cable or must it be just prior to entering the board? ...or maybe in place of the battery? ...and are you thinking this could address both the power and communication cable?



Winegrower said:


> Revert to battery operation. I had these same readouts, maybe I replaced batteries every 6 months.


It's an option.

Best,
Kelly


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## kcoffield (Dec 19, 2020)

homebrewed said:


> Some iGaging users have found that they needed to electrically isolate the scales from the machine.  To do that it's necessary to make replacement mounting blocks out of plastic.  You mentioned the fact that all the machine surfaces are painted, but the screw holes aren't, eh?



The four bolts that secure the lathe to the base aren't threaded into the cabinet or lathe, just through with nuts on the other side. I just need to get the meter and check. So are you saying isolating the gage may be worth a trying as well? It's not just the scale because the back of the sensor is connected with a metallic bracket as well.

Best,
Kelly


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## graham-xrf (Dec 19, 2020)

VFDs are switching high currents at kHz, These cause interference to any kind of lower level data signalling, such as the pulses from a DRO light sensor. There are very many ways the data can get jangled, and fully analyzing even one, all the way to the end, can take too long, and strain even big field theory brains. Fortunately, there are some basic steps to take that can reduce the interference by factors of thousands.

First to know about the pulses, and how they get jangled to make data errors, which software can find unacceptable, and quit altogether.
Most DROs is a fine glass grating scale, so fine it is hardly visible, but not all are that type. There are other technologies, but the LED light reflected sensor on glass scale is the most common. There are normally two scales, one displaced exactly halfway out of step with the other, The light reflection will produce ON/OFF states of light detection in the electronics, which then have to be sent to the measuring electronics as pulse voltages.
It is these voltages that can get contaminated by unwanted, often huge, noise voltages that leave them totally scrambled when it comes to detecting ON and OFF states.

*How it can happen.*
Signal voltages need to be shielded from external electromagnetic interference (EMI), and the ways this can happen are by what is known as "conducted", and another way called "radiated". The ferrite choke you see in the the picture in the previous posting is to choke currents on the outer of the shielding braid, so stopping the cable braid shield from becoming a huge and efficient antenna to switcher noise.

Digital pulse detection circuits, and sensor instrumentation , with their low voltages, are prone to getting messed up if they have a common ground, or zero volt point that is also a "ground" for high current switching circuits. Most commonly, the VFD has AC inputs, motor drive outputs, and an electronics control circuitry power and ground. DO NOT allow the 0V (GND) of the digital sensor power supply to casually share this connection. That is why for many, the "solution" is to use a separate battery DC supply. It keeps the currents apart. This unwanted bounce from sharing a return current route to 0V is called "common mode coupling.

Then there is magnetic coupling. The high frequency ON-OFF pulsing for motor currents generates magnetic fields, which will induce noise into any wires they couple to. Shielding wires in a braided shield will stop transmitted radio frequency fields, in both electric and magnetic, but not direct coupled close-up magnetic couplings.

*Some basic things to do*
Start with the VFD. There will normally be expansive and exact diagrams and connection explanation, Follow them to the letter. The switched wires to the motor terminals should be in a shielded cable intended for this stuff. If single phase, the wires should be spiral, such that any forward current is cancelled by its return current. The connection at the VFD outside the shield must be short, and not allow other wires to "link in" near the terminals. The shield must be bonded properly to the VFD shield connection terminal right there. The shielded route must be maintained all the way to the motor, and the shield connected to the motor frame. This "shield" is not to be confused with the motor AC safety earth wire, usually green/yellow striped.

The physical route of the motor must be kept well away from the sensors, not run parallel, nor laced up together with them. Berfore making the connections, it pays to put ferrite suppression chokes over the outside of the cables at two places. One in near the motor, Another is near the VFD. These suppression chokes need to be chosen for the purpose. They are bulkier than the little chokes seen on monitor leads. They need enough ferrite volume not to be driven into magnetic saturation by unwanted currents going around the motor drive wires. These things block huge interference from "transmitting" into the sensor wires.

*The sensors*
Simply routing the wires away from the possibility of what is called "near-field" coupling immediately cleans up the signals in an impressive way. The danger is if the cables for the sensors visit the same cabinet as the VFD, and have a non-isolated DC 5V supply in there, sharing a ground.
Internal to the sensor cables, one can ensure shielded twisted pair (interference-proof) conductors driven with a technology called "differential signalling" can be used. There are all sorts of technologies to get the pulses across, including resorting to fibre-optics.

For most folks, the cables from the sensors came ready-terminated with DB9 connectors, and they have to live with the wiring arrangements in the sensors unless they want to get up to some advanced noise reduction design. At the very least, I would expect the signals to be shielded twisted pairs, with every signal twisted with it's return, and the 0V not common and bonded to 0V GND ground. Even without peeping into the grounding and shielding of sensor cables, one can win. The only route left to bounce the signals around with switcher noise, is up the power supply wires. The simple expedient of using a power supply, isolated from the VFD currents, with a bit of a shield, and some braid over it _grounded at one end only_
can hugely clean up the signal. Putting inductive chokes in series, and one capacitor across the DC power leads can also make a difference.

*But the screen over the wires "makes no difference".*
That only means you have not found the coupling mechanism yet. If the basic precautions are used, nearly every system can be brought to the point the coupled noise is no longer a problem. Some VFDs are exceptionally rowdy, and need inductive + capacitive storage filter on the mains input to stop them distorting the mains waveform, and using the house wiring as a massive interference antenna. Agreed that EMC problems can be frustrating and intractable, but I assure you that however bad, once the route and type of coupling is identified, it can be put down, It is possible to return clean digital signals from sensors right inside motors as powerful as 110kW, which is the largest I ever personally dealt with.

When "adding a screen" can seem to make things worse, it is an indication the screen is being used as an antenna to help the coupling. Disconnecting one end of the screen, and using a couple of suppressors will bring that mechanism to a halt. Leaving both ends connected, but adding chokes can work. That is why the chokes are also called "braid breakers". They stop interference currents

If all else fails, then terminating the sensor leads with the correct resistive load, and using differential connected oscilloscope measurement, while checking out the VFD is the diagnostic route. Nobody should have to go that far. I only ever did it twice.

*The hidden common mode earth.*
The frame of the mill/lathe, whatever. A long route of ground safety earth wire, correctly doing its job as a safety earth, but coupling the father and mother of noise into the DRO power supply via the mains input connection. A input power low-pass filter to the VFD, having both common mode and differential filter components can block that. Even mounting the sensor on an insulating sheet, can defeat this route. In the end, imagine you are approaching the machine, VFD blazing away, and all the DRO kit in your arms, battery powered. If as you get closer, the DRO starts suffering, then the entire mechanism must be by radiated RF fields. There are almost zero situations where it can be so bad. Reasonable quality VFD's should have EMC filters internal. Adding a filter outside of it is a low cost fix.

I do accept that if you have not teased out how it is happening, it can be a right b**ch to solve. Do not expect there is just a single connection, or fix recipe. Even if it appears to "all come right", the noise margin may be very little.

*"Quick fixes"*
"Put a capacitor across it". That depends where. Never across the signals. Definitely across the power supply. having each lead (+) and (-) go through a 1mH inductor choke right at the powers supply terminals, and a capacitor 1uF to 10uF across the supply both before and after the choke can magnificently clean up the supply.

My apologies for the long posting. The subject has filled big books. I can't say you find a quick fix in any of this. I just know that installing with all this in mind should help avoid the worst.


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## kcoffield (Dec 19, 2020)

I may have had a stroke of luck identifying the source of the problem. 

I went out to the shop and figured I'd do some easy stuff for process of elimination. I powered everything up and to my surprise, everything is working fine with the VFD on _and_ motor running at all speeds. What the heck? Then I noticed the 5vdc wall wart power supply laying by itself in the drip pan. I had not reinstalled it after my last test last night. 

When I was testing the DRO power cables for being the possible source of interference, I was just disconnecting them at the DRO but leaving the other end of the cable plugged into the wall wart PS. Sure enough, when I plugged the wall wart and cables back in, it took the displays down even though the barrel jacks were not connected at the DRO end. If I run the DROs on battery and keep both ends of the DRO power cables disconnected everything is fine even with the DRO control cable extensions run through/near the VFD, they don't seem to be a problem. 

The power cables are bundled and run side by side with the two Micro B USB extension cables that run to the DRO displays, so.......it appears the interference may be conducted through the wall wart PS into the DRO power cables and then radiated to the adjacent DRO control extension cables. I say conducted to/through the wall wart PS because if I plug the wall wart into a separate 120 vac circuit via extension cord, and use a loose cable to connect to the 5vdc to the DRO display, both completely away from the VFD, it still introduces the same interference and takes it down DRO displays.

I did try snapping this ferrite core I had from an old audio power strip around the DRO power cables right where the exit the wall wart......no affect.




_Maybe all I need is a real 5-6vdc power supply instead of the wall wart? or maybe just a filter on the ac power supply line to the wall wart? Hmmmm? What do you guys think? _

I did check grounding. The lathe, cabinet, and backsplash are all earth grounded. So are the DRO magnetic scales. I can see continuity to ground by touching the exposed end of the cross slide scale and the grounding post in the electrical enclosure or any bare metal.

Best,
Kelly


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## homebrewed (Dec 19, 2020)

kcoffield said:


> Could the cap be applied anywhere along the cable or must it be just prior to entering the board? ...or maybe in place of the battery? ...and are you thinking this could address both the power and communication cable?



You will want the cap installed as close as possible to the noise-sensitive circuitry.  If there's a significant length of cable between the cap and sensor, that will act like an antenna.  With high speed noise, cables don't act like simple low-resistance connections so even a short length of cable could pretty much negate any benefit you might see from the capacitor.

For the same reason, you don't want to place the capacitor on the battery side of the cable.  If the DRO design is similar to mine, the batteries are in the control/display box....on the wrong end of that long cable.  You can't simply replace the batteries with a capacitor because when you plug the external power connector in, that disconnects the batteries.

Since my generation of DRO doesn't have the option for external power, I can't tell you if shielding the power cable will work or not.  If you try it, you will need to connect the shield to the DRO ground.  That's a bit problematic because its ground isn't brought out.  A snap-on inductor might be the best solution for the power cable.  Place it close to where the cable plugs into the DRO box.

iGaging DROs use capacitive sensing to track position so they inherently are more sensitive to electrical noise, compared to an optical or magnetic type of sensor.  That's the price you pay for a lower-priced DRO.

I just saw your post regarding the wall-wart relationship to the problem.  If it is a switcher-type supply those are reported to have poor isolation between the AC input and the DC output.  A transformer-based power supply should reduce or eliminate that.  You can get that type if you shop around.  An isolation transformer would probably help if you want to keep your current power supply, but one of those will cost more than the right kind of wall-wart supply.


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## kcoffield (Dec 19, 2020)

homebrewed said:


> I just saw your post regarding the wall-wart relationship to the problem. If it is a switcher-type supply those are reported to have poor isolation between the AC input and the DC output. A transformer-based power supply should reduce or eliminate that. You can get that type if you shop around. An isolation transformer would probably help if you want to keep your current power supply, but one of those will cost more than the right kind of wall-wart supply.



I think we were posting at the same time. That's exactly what I was thinking. I'll have to root around and see if I have an older transformer style 5vdc supply.

One other curious thing, that receptacle in the electrical enclosure where the wall wart is plugged in is switched. For grins, I turned it off but left the wart and cables plugged in. It still created the DRO display interference even though it wasn't powered up, so maybe it is not purely conducted and that location to the VFD is vary high radiation, but, there was still interference even with the wall wart removed and plugged into another circuit. Also, if I just unplug the wart and leave it lay by the receptacle on top the VFD with the cables plugged in, there are no interference problems.

This is a picture looking up into the VFD. Those three devices circled are sinked to the wall immediately adjacent to that receptacle where the wall wart is plugged in. Any idea what they might be? Looks like a 3ph power switching device......solid state relays maybe?




I did quickly place that ferrite core at the DRO end of the cable. The display was still unstable but not quite a crazy without the core in place.

Thanks for the replies and help.

Best,
Kelly


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## homebrewed (Dec 19, 2020)

Those 3 devices could be the main power switches for the VFD output.  If so, there's plenty of switching noise running around that part of the board.  However, since you moved the wall-wart to a more remote power plug and still had a problem, it seems unlikely that the proximity to the VFD is the cause of your problem.

If you've got more of those ferrite cores lying around try putting one around the AC line going to the VFD.  It could be sending a lot of noise back into the AC mains.  You also can get power line filters for not a lot of money.  I have one & tried it on my mill but unfortunately that didn't cure my problem.....


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## markba633csi (Dec 19, 2020)

I agree that a regulated linear supply would be preferable to a switcher for the dro power.  Or maybe even just a transformer-style wall wart followed by a three terminal regulator like a LM317 device
-Mark
As a test you could try some batteries at the end of the cables in place of the switcher- if it works then you know the supply is suspect. If not then you know the emi is being picked up directly by the cables, acting like antennas

If you get some improvement with the ferrite core, try coiling up the wire so it goes several times thru the hole and see if it improves even further


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## kcoffield (Dec 20, 2020)

homebrewed said:


> If you've got more of those ferrite cores lying around try putting one around the AC line going to the VFD. It could be sending a lot of noise back into the AC mains.


I did move the ferrite core there and no change, but I think it is pretty clear there is back EMI fed into my entire shop AC supply by the VFD because of the earlier test isolating the wall wart to a different shop circuit and cable still creating interference.


markba633csi said:


> As a test you could try some batteries at the end of the cables in place of the switcher- if it works then you know the supply is suspect. If not then you know the emi is being picked up directly by the cables, acting like antennas


Thanks for this suggestion. I had forgotten I had this auxiliary battery pack for mobile phones given to me several years ago. I don’t think I’ve ever used it but when I was rooting around for wall warts and cables and saw a 5vdc battery source with two USB ports, I knew what to do with it. It certainly looks the part.




I couldn’t find an old transformer style 5vdc wall wart laying around but I don’t think it matters because I’ve all but convinced myself the problem is the power cables that plug into that wart are probably unshielded antennas and I literally have four feet of those two cables taped side by side with the DRO control cables. As further aggravation, there is an additional two feet of the power cables coiled up in the electrical enclosure in a 3” diameter coil which may be a good receiver.




So I charged it and plugged in the power cables while holding it in my hand and used a loose cable to connect to the DRO away from the VFD and cables. It powered them fine with and without the VFD powered up . Same thing when I connected the cables in the cabinet without the VFD powered up but as soon as I powered up the VFD down went the DROs. The odd thing was, even when I disconnected the barrel jacks at the DROs, they still were scrambled unless I disconnected the battery at the other end. So then I plugged the cables back into the battery and started changing the position of the power cables in the enclosure and when I pulled the battery and 3” coil of excess power cable out of the electrical enclosure, the DROs recovered, but I still could not plug the barrel jacks into the DRO and run them off the remote battery through the cables.

This is more of an intellectual curiosity, but does the cable radiate more when it’s also energized…..even with just 5vdc? Because when the battery is disconnected and the cables inside the enclosure, they don’t broadcast enough to take down the DROs.

So, a number of options here, but I may need to decide how much effort I want to put into solving an EMI problem for what may not be much of a battery problem. I’ve done more for less…..but not recently .

I could remove the additional two feet of power cable coil by either cutting it out or just move it to the other end at the DROs, shield the power cable with braided sleeve, and/or simply route the power cables separately from the control cables instead of tightly joined to them. There may still be a conducted problem with the wall wart if I do that. I have a 12vdc to 5 vdc converter typical of what’s used for cars, RVs, ATVs, etc and I suspect my little 12vdc power supply has a relatively clean dc output. I see a small onboard transformer and that tachometer circuit has no issues. Not sure I want to resort to circuit board surgery. I don't have fine soldering equipment.
I bet I could power those DROs a long, long, time with that battery pack, and just mount it on the backside of the DRO displays with a short stub cable to each DRO. Problem would be if I could remember to turn it off…LoL.
Best,
Kelly


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## homebrewed (Dec 20, 2020)

The coiled-up cable probably is acting like an inductive pickup.  The noise pickup increases as the coil diameter increases, so shortening it as much as possible (to eliminate the coiled-up cable) would minimize the noise (but perhaps not enough).  Your rechargeable battery should keep the DROs running a long time so if it works for you, you're golden.

Eliminating noise can be a bear -- every situation is different, and the noise can come from different sources.  Ground loops, electromagnetic noise, you name it.  In the end, experimenting and keeping track of what does and doesn't help is about the only way to address the problem.  And don't ignore what Lady Serendipity hands you.


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## markba633csi (Dec 20, 2020)

You definitely should separate the power cables from the control cables.  That I consider a must-do.  Then, perhaps, shortening the excess cable and adding some ferrite cores might get you there.
Homebrewed is absolutely right- there is no set way to do this. You might need only one fix or several. Often, in industry (where I dealt with this a lot) a circuit would work fine as a rat's nest mess but not after tidying up.  I cut off a lot of ty-wraps tracking problems like these.
Having access to a wideband oscilloscope can get you there faster but it doesn't eliminate the need for experimentation
-Mark


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## Jim F (Dec 20, 2020)

I think you found the problem and missed it.
With battery power the DRO works, when powered they go crazy.
Move the warts to a receptacle away from the VFD controller.


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## kcoffield (Dec 20, 2020)

Jim F said:


> i think you found the problem and missed it. With battery power the DRO works, when powered they go crazy. Move the warts to a receptacle away from the VFD controller.



Yah, you'd have to read up the thread Jim but I did that and there is obviously a conducted back-EMI problem from the VFD as well because I moved that wart to a completely different circuit within my shop via drop cord and loose DC power cable in "free air" away from the VFD and still had interference.....but thanks for the reply.

Best,
Kelly


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## Jim F (Dec 20, 2020)

kcoffield said:


> Yah, you'd have to read up the thread Jim but I did that and there is obviously a conducted back-EMI problem from the VFD as well because I moved that wart to a completely different circuit within my shop via drop cord and loose DC power cable in "free air" away from the VFD and still had interference.....but thanks for the reply.
> 
> Best,
> Kelly


Sorry, must have missed that.


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## chip maker (Dec 21, 2020)

Maybe I'm a bit out of line here but for all the tail chasing and the work involed why not just use the batteries? I have three installed on my lathe and two on my mill and don't go thru hardly any batteries. I purchase them on e bay by the 100 and are really inexpensive. Just my 2 cents sorry for butting in.


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## kcoffield (Dec 21, 2020)

chip maker said:


> Maybe I'm a bit out of line here but for all the tail chasing and the work involed why not just use the batteries?


No worrys. The short answer is because I already had to run the control cables, had the wall wart, and the power cable extensions were only $4......so why not.......answer: because they introduce EMI/RFI. So why did iGaging provision the DRO with a power port?


chip maker said:


> ......I have three installed on my lathe and two on my mill and don't go thru hardly any batteries. I purchase them on e bay by the 100 and are really inexpensive. Just my 2 cents sorry for butting


If you only have 5 DROs total on two machines, and you don't go through hardly any batteries, why to you buy them by the 100s?

Best,
Kelly


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## kcoffield (Dec 21, 2020)

I'm going to make one more run at fixing the RFI/EMI problem because I suspect I may have other issues in the shop induced by the VFD later down the line and I may be able learn something here and maybe it will help someone else. I have a CNC router with long run times and soon to be 3D printer with same. I've already had the CNC router exhibit self induced RFI problems that needed to be fixed. Wouldn't be the end of the world if I could run the lathe while those were running but certainly suboptimal.

There is definitely a conducted EMI problem with the VFD too because with it switched on, I can't power the iGaging DROs from the wall wart in any shop receptacle away from the lathe, but switch off the VFD and it powers up and displays well from anywhere, so the VFD is conducting back EMI/RFI through all my shop circuits.

I bought some cheap parts but they may take a few days to receive them with the holiday season. I do have couple questions _*I'll pose later below*_. 

If no success, I'm happy to just run the DROs off of battery but it won't be that fancy battery pack in the post above. Turns out, that battery is meant to _re-charge_ a phone battery not be a power source, and when it senses low draw for 30 seconds or so, it shuts off as sensing it has charged the phone battery. The DROs don't draw enough to keep it active. So some of what I thought were the DROs being taken down by RFI while the battery was plugged in was really just the battery pack shutting off, and when that happens, the DRO bypasses the internal coin cell battery because it senses the barrel plug in the socket, but doesn't have power......good grief.

One other tidbit I hadn't previously mentioned, when I rec'd the VFD, as I was reading the manual, it said it cannot be operated on a GFI circuit. Well, code required all the 120vac circuits in a garage to be GFI. There is a custom version of the VFD for GFI circuits that has both hardware and software differences and cost twice as much so probably wouldn't have bought it even if I had known. I just removed the GFI receptacle and installed a non-GFI receptacle. I know what the GFI does but not sure how/if the mechanism could affect this conducted EMI problem. I think the reason the VFD won't work on GFI circuit has to do how it senses current for overload protection and maybe even switching functions. This may also prevent me from installing any inline suppression devices which may mean the lathe simply doesn't run while other sensitive equipment in the shop runs. I'll put that question to the VFD manufacture.

*So the RFI fix questions are:*

I have braided shielding I can pull over the cables. Probably won't do anything but I have plenty of it. _*Is suspect it is better to shield the power cables since they are the source rather than the control cables. Is that so?*_ Could do both and I will reroute the control and power cables apart from one another to extent possible.
I bought an assortment of ferrite beads, two dozen for $9 delivered in different sizes. I have a few spots on my CNC router that could use them too. They are cheapies and I don't know what the core material is or intended frequency range, but even if I did, I wouldn't know which one to select. I'll try them in single pass and looped. _*Should they be placed on both ends of the power cables?*_ I may also place a couple more on the supply power to/from the VFD. _*I presume the cable should not be have braided shielding in the area of the beads. Is that so?*_
For the conducted part of the problem, I bought a 12vdc to 5vdc Buck Convertor, thinking my 12vdc from the regulated supply seems to be a clean source. It's only a $10 part but I need one for my ATV so if it doesn't work on the DRO, I'll use it there. I don't know much about those. *Is it like to be another source of noise? *
Funny how everything becomes a ball rolling down hill. Thanks for playing along.

Best,
Kelly


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## chip maker (Dec 21, 2020)

kcoffield said:


> No worrys. The short answer is because I already had to run the control cables, had the wall wart, and the power cable extensions were only $4......so why not.......answer: because they introduce EMI/RFI. So why did iGaging provision the DRO with a power port?
> 
> If you only have 5 DROs total on two machines, and you don't go through hardly any batteries, why to you buy them by the 100s?
> 
> ...


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## chip maker (Dec 21, 2020)

Sorry misprinted I purchase them by 25 at .36 cents a piece. I not only have the 5 Igage but also about 4 other things that use the same battery size. At the regular stores these are like 3.00 for 2 batteries.


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## markba633csi (Dec 21, 2020)

I think you will find the ferrite cores most effective right close to the dro units, as close as possible.  So run the shielding up to the cores but not thru.  Use one core for the power cables and one for the controls 
Now, as far as grounding the shields, that might take some experimentation and you may not need to ground them at all.  Can't advise you there. 
As far as the buck convertor, it's worth a shot.  
-Mark


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## kcoffield (Dec 23, 2020)

I received the Buck DC-DC convertor and installed it downstream of my 12vdc voltage supply.




Like before, fine with the VFD off but no display on the DRO with the VFD on, and the display came right back when I toggled off the VFD.

So then I installed ferrite bead with 3 loops on the DRO end of the power cables.




Still the same result when I added a bead on each end of the cables…..scrambled and or blank display when the VFD was switched on but recovery when it was switched off.

The cables were separated from each other in all instances. With those results I wasn’t willing to put the effort into pulling braided shielding over the cables. It doesn’t seem to have worked for anyone who has posted, but I did decide to see if isolating the scales from ground had any affect.

The easiest way for me to test that was to unmount the cross slide DRO, so I did…..It had no effect.

I didn’t try adding a cap across Vcc and ground, even though it appears that is the only thing that has worked for Homebrewed and RJSakowski in the other thread.…..









						Battery replacement for battery-only Igaging DROs?
					

RJ, what size was the cap and can you elaborate a little on exactly how/where it was installed? I have a similar problem described here: https://www.hobby-machinist.com/threads/igaging-dro-emi-problem.89275/  Best, Kelly  I used a .05 mfd ceramic disk capacitor in parallel w2ith aa 10 mfd...




					www.hobby-machinist.com
				




…..it’s just not worth at this point to me for what might be a more or less a non-issue. If the extensions of the control signal cables didn’t work that would have been a bigger problem for me but running the DROs on batteries is not.

I will say, I cannot plug the DROs into any kind of remote power source in any circuit in my shop while the VFD is switched on which makes me think that it is really polluting my power source and I suspect I won’t be able to operate the lathe along with any other sensitive equipment in my shop. Either KB’s VFD is a very bad actor as far as back EMI or iGaging did zip to protect there displays when they added the remote power provision. I may eventually need to place a call to KB on this.

Best,
Kelly


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## pontiac428 (Dec 23, 2020)

@kcoffield, you should try the iron beads on the signal wires, that's what they are meant for.  Your power wires should not be an issue.


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## homebrewed (Dec 24, 2020)

I think you will want to connect the shields to each DRO's internal ground bus, IF you decide to try it.  When I was fighting my EMI problem I put shields over the cables and found that the best EMI reduction (not elimination unfortunately) was with that connection.  Problem is, the ground bus isn't readily accessible unless you either: (1) cut open the USB cable and access the ground line; or (2) open the display box, solder a wire to GND and bring it out of the box.  Both make for an ugly look, to put it mildly.  In your case, GND is sort of available via the external power receptacle, but if you plug anything into it, the internal batteries are disconnected.  Sort of a conundrum there.

I have a suggestion that might work for you, considering the fact that your DROs work OK on batteries.  It will require a modification of the external power cable, and getting a few capacitors and resistors.  There will be a small voltage drop across the resistors, but the current generation of iGaging DROs draw so little current that it will be just a few milli-volts.  Anyway, here's the circuit:




To make this, cut the power cable close to the connector and expose the wires on both sides of the cut.  You will want to make sure that the wall-wart's +V is connected to the plug +v (through R1), and the same for the GND connection through R2.  Reversing the connections will likely kill your DRO, you have been warned!  Use heat shrink tubing to insulate the connections, then a larger-diameter piece to cover the whole thing up.  You can use an electrolytic capacitor, just make sure the "+" terminal connects to +V if you do.  Try this on one DRO first to make sure it WILL work, eh?  And double-check that the polarity is correct on the plug terminals before you plug it into your DRO.  The wall-wart should indicate if the center is positive or negative.

It is a filter that will remove the EMI and keep it from polluting the DRO's Vcc and GND busses.  It actually improves on what I did to fix my problem, but without needing to open up the sensor box and cut a circuit board trace to do it.

I wouldn't use this in combination with shielding.  Connecting shielding up to the DRO ground would likely reduce the effectiveness of the filter network.  If you want to use shielding, connect it to the wall-wart GND line.


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## kcoffield (Dec 25, 2020)

pontiac428 said:


> @kcoffield, you should try the iron beads on the signal wires, that's what they are meant for.  Your power wires should not be an issue.


Since I still had the buck convertor in series with the 12vdc power supply, it just took a couple minutes to wrap on the bead and try.....but same result, no operation with the VFD switched on and power supplied instead of battery operation.




They always scramble and then completely shut down. When the VFD os off or revert to battery power they recover, but always in mm units of display.



homebrewed said:


> ....I have a suggestion that might work for you,....



I can do that, but not being an electronics guy, I don't have those components or anything to harvest them from so will need to buy them, but looks like I can do so and get a jillion of them delivered to my door for under $9. I seem to have a good collection of low quality power cables to experiment with so that shouldn't be a problem. Anything special about the resistor as far as power or type of cap?

Best,
Kelly


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## homebrewed (Dec 25, 2020)

kcoffield said:


> Anything special about the resistor as far as power or type of cap?


The current draw is extremely low, so quarter-watt or smaller resistors would be just fine.  Just about any capacitor in the low-microfarad range will work, whether it's a film capacitor, ceramic capacitor or electrolytic.  Since the values aren't all that critical you can go with 10% tolerance values on the resistors.  Capacitor tolerance can be +/-20%.

I don't know who your go-to vendor is for electronic components, but just for examples on what would work I went to Jameco.com and did a little searching.  For capacitors, something like their P/N 10866 would be fine.  It's a 1uF 50V 20% electrolytic that costs $.59 in singles (so you will need to connect them up correctly).  The best price I found for a 1uF film capacitor was $.79 (P/N 231239).  A .25 watt 1K 5% carbon film resistor will cost you $.06 but you have to buy ten of them, oh dear .  P/N 690865.  The shipping may cost more than the parts.

BTW, the sensor is powered from the USB cable (what you're calling the control cable).  Since the display unit provides the power that means there's a good chance that the power at the sensor end is polluted with EMI, too.  RJ and I both found that installing capacitors between Vcc and Gnd at the sensor end helped a lot, so you might as well order enough capacitors to do that if you need to.


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## kcoffield (Dec 25, 2020)

homebrewed said:


> .....I don't know who your go-to vendor is for electronic components, but just for examples on what would work I went to Jameco.com and did a little searching.



Not being an electronics guy, I don't really have a go-to, and thanks for that lead. Turns out Jameco has a $10 surcharge on orders <$20 so that would be on top of product and shipping cost. They're common parts so being a Prime member shipping is free, so for ~$9 I have 100 resistors and 50 caps heading my way via Amazon......says Tuesday delivery but in any case should be next week. I'll let you know how I do. Thanks for your help.

Best,
Kelly


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## homebrewed (Dec 25, 2020)

kcoffield said:


> Not being an electronics guy, I don't really have a go-to, and thanks for that lead. Turns out they have a $10 surcharge on orders <$20 so that would be on top of product and shipping cost. They're common parts so being a Prime member shipping is free, so for ~$9 I have 100 resistors and 50 caps heading my way via Amazon......says Tuesday delivery but in any case should be next week. I'll let you know how I do. Thanks for your help.
> 
> Best,
> Kelly


It sounds like you got a good deal!  Have fun!


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## kcoffield (Dec 31, 2020)

Well homebrewed, I rec’d the resistors and caps, soldered them in, and that *almost* did it. It’s a tremendous improvement. As before, it operates normally without the VFD on. With VFD switched on it’s mostly stable but will twitches every 3-5 seconds. When it does, it’s just a brief flash or two, but looks like sometimes it’s jumping to mm scale and other times just to nonsense values, but does recover to the correct position, only to twitch again in a few seconds. It doesn’t seem to matter what RPM the motor is running at or if it’s running at all…….just VFD switched on.




Best,
Kelly


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## homebrewed (Dec 31, 2020)

kcoffield said:


> Well homebrewed, I rec’d the resistors and caps, soldered them in, and that *almost* did it. It’s a tremendous improvement. As before, it operates normally without the VFD on. With VFD switched on it’s mostly stable but will twitches every 3-5 seconds. When it does, it’s just a brief flash or two, but looks like sometimes it’s jumping to mm scale and other times just to nonsense values, but does recover to the correct position, only to twitch again in a few seconds. It doesn’t seem to matter what RPM the motor is running at or if it’s running at all…….just VFD switched on.
> 
> View attachment 349392
> 
> ...


That's progress for sure.  I think your next step is to add additional capacitance inside the sensor box (the one that slides over the rule).  The symptoms you have now suggest voltage fluctuations getting into it via the USB cable....they're very similar to what I observed when I was fighting my EMI problem.  You just couldn't separate which was which until you did the power cable mod.  Which, by the way, looks pretty clean -- good job!

You should have plenty of capacitors to do the additional mod, and have some left over for other things.


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## kcoffield (Jan 1, 2021)

Appreciate your help homebrewed but think I'm going to pull the plug on this one (sorry couldn't resist  ), at least for the time being.

It doesn't make sense for me to invest more time and start doing surgery on working equipment when I have something that works. I'll see how the 25 cent batteries hold up for now and spend my time getting the lathe dialed in.

Clearly not my field, but given that data and power seem to be communicated just fine across long cheap USB cable extensions that run right adjacent to the VFD, and the sensors/scales see the same ground as the VFD and everything, do you think I'd be off base to say iGaging added the power barrel jack as an after thought with no real thought whatsoever to isolating it from external interference?

Best,
Kelly


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## homebrewed (Jan 1, 2021)

kcoffield said:


> Appreciate your help homebrewed but think I'm going to pull the plug on this one (sorry couldn't resist  ), at least for the time being.
> 
> It doesn't make sense for me to invest more time and start doing surgery on working equipment when I have something that works. I'll see how the 25 cent batteries hold up for now and spend my time getting the lathe dialed in.
> 
> ...


Hi Kelly,
Yes, it seems pretty likely that the external power option is an afterthought.  It doesn't appear to have been well-vetted before being sent out the door.

The main reason I spent a lot of time on my iGaging problem was that even battery operation did not take care of EMI issues with the stock DROs.  That and the fact that the older ones consume a lot more current, so I really go through the batteries.  I'm working on that and think I have a solution, but I'm applying it to DROs that have already been heavily modified.

I have a couple of newer iGaging DROs (for my lathe) that have much lower power consumption so for the time being I'm sticking with batteries for those.  However, even there I had to install capacitors on the sensor board to tame the EMI!!


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## kcoffield (Jan 1, 2021)

homebrewed said:


> I have a couple of newer iGaging DROs (for my lathe) that have much lower power consumption so for the time being I'm sticking with batteries for those. However, even there I had to install capacitors on the sensor board to tame the EMI!!



Well so far that is not the case for me. All is well on battery power. I fear the law of unintended consequences.......start jacking with the micro USB cables and risk creating a new problem!

Best,
Kelly


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## kcoffield (Jan 7, 2021)

I happened to come across this post while browsing new posts.









						Another Home Made Shop Jib Crane
					

I did not find a specific catagory to put my post so here it is in the general projects.  Tony, feel free to move it to a proper catagory if necessary.  I've built two other jib cranes for use in my shop a few years back.  There's pictures of them on both this site and the other web site out...




					www.hobby-machinist.com
				




There was a link to these Roxburgh power filters at Automation direct which is a familiar supplier to me.

Roxburgh 1-Phase Drive-Rated Power Line EMI / RF Filters | Power Products (Electrical) | Products | AutomationDirect




Given the VFD is clearly polluting my shop AC supply, I thought I’d experiment with these two power filters, using one to isolate the VFD and the other on my CNC router controller.

Both of these power filters were an improvement when used with or without the inline R/C DC DRO power cable filter, but I would say the higher end filter actually _“works”_ when used with the R/C filter fitted to DC DRO cable. Initially when the VFD is powered up the DRO display is a little twitchy, then settles down to just an occasional blip that quickly recovers. But when I actually turn the 3ph motor on the display becomes rock stable and stays that way regardless of the motor state afterward. This is with the DRO power source coming through a 12vdc regulated supply and buck convertor to 5 vdc.

When I move the DRO power source to a wall wart on a different AC circuit, also with the inline resistor/cap cable filter, it is also quite stable. If I remove the inline power filter isolating the VFD, the DRO immediately crashes. Though somewhat better, neither are sufficiently stable without the inline R/C filter. So, I think it probably has helped to some degree suppress the back EMI to the shop AC supply, I was thinking a nice way to package the R/C filters could just be an inline can on the back of the DRO mount with a female barrel jack on one end and a short pig tale/mail jack to the DRO on the other. There’d be plenty of room for other components that way. Any other ways to improve that portion of the filtering external to the DRO?

Thoughts?

Best,
Kelly


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## homebrewed (Jan 8, 2021)

If it works, go for it!  

EMI problems can be difficult to solve, and the solution can be unique to every system.  So a trial and error approach, while possibly time-consuming, often is the best way to go.


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## Marbles (Feb 6, 2021)

I have access to a LMC 3900 Bench Top Mill at work. With iGaging DRO that I installed years ago, it would do incredible work. The DRO's started to fail from oil going everywhere. I took the sense heads apart once and cleaned them and got another year or two out of them. More close accuracy work to do required new iGaging DRO for X,Y, Z travels. I made and installed way covers and no more spray lubes allowed. New style heads required new mounting area and cable runs. With power off they worked slick.

Then I started milling some material and the readouts failed to hold zero and skipped all over the place with numbers.

Started the process

>Replaced batteries
fail
>Reroute wires
fail
>failure occurs only when the power is turned on, spindle turning at any speed

> On line search for iGaging problems, not good, lots of suggestions no working answers

Get out the Volt Ohm Meter VOM)

>Measure Volts AC  with VOM, especially spindle which is not grounded except through bearings and is isolated by belt drive from motor

>Check grounds at machine and to wall receptacle
OK

>Check the service entrance ground wire, clamp and rod
OK

>Scales are mounted to painted support clamps that vary in resistance to machine ground

>Install ground strap on X axis scale using 4-40 tapped holes and machine screws with lock washers on ring lugs of strap.
fail

>Set up the oscilloscope and find source of problem


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## Marbles (Feb 6, 2021)

> There is a high rise time positive and negative burst at about 15KHz when the power is applied to the motor drive. This burst changes amplitude when the spindle is grounded to the table. The speed control pulse width modulated signal from the drive can also be seen.

Installed ferrite cable clamps on the X DRO near display and near scale.

Fail

> Open DRO scale case, there is a brass contact strip on the scale aluminum body that is used for connected to the circuit board.

Grounding the scale to the mill table made the problem worse since the interfering signal is now directly coupled to the readout.

Inspection of the micro usb connectors at each end of the cable revealed five individual insulated strand ed wires with soft plastic insulation. The foil wrapped shielding was not connected at either end micro connector shell.

> Where the scale mounting clamps contact the scale, wrap the scale ends with kapton tape to insulate the scale body from ground. On this installation the scale pickup is mounted to the table with G10 0.065” insulating material and need not be isolated from the mill table. Remove the ground jumper from the scale body to the mill table.

> The ground jumper was made using two 18-22 crimp ring with a #6 ring. The bonding wire was 26AWG PTFE insulated stranded tinned copper wire. To install a decoupling capacitor I cut the bonding wire at center and soldered in a 390pF tantalum capacitor.

>Operated mill, placed a 1-2-3 block on the table and cranked the table until the spinning spindle hit the block to simulate a cutting tool engaging the work. It lightly touches and causes no scratches but it is a terrific noise generator.

Fail

> Used the oscilloscope scope, and no appreciable change to noise

> Removed the 390pF and installed a 2.2uF Tantalum. Repeated the  1-2-3 block on the table test and no issues. Checked with the scope, no noise signal present at any spindle speed.

Pass


End of the day so I think it was worthy. Engineer stopped by who was helpful in this work. He can’t have his R&D parts until the DRO was operational. He insisted I publish the results.

When troubleshooting, don’t guess. Be methodical and start from the very basic items required for operation. Do that every single time you troubleshoot.


This solution made the DRO operational. Your application may be different or have different problems.  Because this DRO system is susceptible to electrical noise, I would use general practice for cable routing.

Marbles


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## Marbles (Feb 6, 2021)

I am using a digital oscilloscope with a 10-1 probe set to 1. Ground of the probe is not used. Probe tip touched to spindle, mill table, scale body, vertical column to make noise measurements. 60 Hz is detectable and the pulse rides on the 60Hz. 

This was done a lab environment using safety precautions.

Safety First and if you don't know, educate yourself please.


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## Marbles (Feb 8, 2021)

Got to have pictures. Took two this morning. This is the DRO and the scale that shows the 4-40 threaded hole and Kapton tape. Vinyl electrical tape will work too if you keep oil off it so the adhesive doesn't fail and get gooey. 




Next is the ground strap I started with, cut in two, and used a 2.2uF. When the scale is mounted, the free end shown below will be secured to the scale with a 4-40 by 1/4" hex drive screw with lock washer.


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## Marbles (Feb 9, 2021)

I got everything mounted and wired. 

Still have failure in DRO as they wander.

Back to troubleshooting!


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## homebrewed (Feb 9, 2021)

I found that hardwiring the scale to the DRO's internal ground, along with soldering 1uF caps across the sensor's Vcc and Ground, worked for me. The sliding contact to the scale doesn't seem to work very well, at least not for aluminum scales.   Just the caps have worked for some, it seems to depend on each individual machine the DROs are installed on.

From what I've observed, noise can affect the DRO in two different ways.  One is where it gets into the clock and data lines, causing temporary glitches in the display that stabilize after the noise source is turned off.  The other way is that it apparently causes the power supply voltage the sensor "sees" to bounce around a lot.  When this happens, the displayed position changes and doesn't recover when the noise goes away.  My problem seemed to be mostly (but not exclusively) due to the latter issue, hence the added caps between Vcc and Gnd.

Some have suggested putting RC filters on the clock and data lines to filter out the noise, but I think that would be problematic.  The display unit generates the clock and the sensor unit generates the data, which is synchronized to the clock signal.  If the clock line is filtered, the sensor "sees" a delayed clock, thus delaying its data output; and filtering the data line results in a further-delayed data signal going back to the display.  The receiver could miss the data transitions.  You could write some code for an Arduino or the like that takes the delays into account, but if I had to go that far I'd think hard about going to a real DRO combo -- magnetic/optical scales + display.


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## RJSakowski (Feb 9, 2021)

My iGaging setup is somewhat different in that it is an earlier version.  I also use the TouchDRO and an Android tablet for my readout.  I had problems with sudden jumps to som e multiple of .2 when my lathe motor was switched off.  Adding capacitors across the supply lines in the pickup heads removed almost all of the problem.  I added a solid state relay to replace the mechanical switch for the motor which eliminated switch bounce and this solved the problem.

Another issue that I see is that the readout would momentarily stop updating on occasion.  When it resumed, no counts had been lost.  This indicated to me that the actual counting took place in the pickup and the updated ascii data was being sent to the readout.  I suspect that it occurs because of the Android tablet rather than than the iGaging scales or the TouchDRO adapter. While it is annoying, it hasn't been a deal stopper.


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## Marbles (Feb 10, 2021)

Yes, when the stop switch is used, some multiple of 0.2 occurs.  I imagine there was a person or two that designed the original dro that worked great. Then the new kids showed up with their cut and paste designs and zero knowledge of noise coupling. Increase the price on the new model and it doesn't work so just cut follow up and support. One comment that I just loved was "they use whatever cable falls off the truck that day". Well eventually the bugs will be fixed and we will have stable dro at a great price!


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## RJSakowski (Feb 10, 2021)

The ability to reject electromagnetic interference is EMC or electromagnetic compatibility.  The measure of generated electromagnetic interference is EMI.  A good part of the problem for me at least, arose with the EMI part.  The filter capacitors in the pickups greatly reduced interference but the final solution was to replace the noisy power switch in the lathe with a solid state relay.

Frankly, with an electronic lead screw and DRO on the lathe, I am surprised that there isn't more interference.  I am currently working on replacing my OEM notor with a PWM controlled brush type DC motor which is literally switching on and off a 10,00 times a second and with the experimental setup, wires a strewn all over and yet, I have had no problems with either the DRO or the ELS..


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## Marbles (May 5, 2021)

The final solution for the setup on the Mill was to replace the non shielded cables with shielded cables cut to length needed for each axis. Bypass capacitors remain on the insulated scales from ground. Cured the Y, Z axis, but X axis required 2 ferrite cores using one at scale and on at the head. The next step would have been to use bypass cap on VCC but was not required on this set up.

In the future, iGaging will be off the list for DRO. I love most of the stuff from China as the quality is usually miles ahead of the junk made in US, and the prices are affordable. 

At this point the setup works awesome and I am only out some free time.


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