Question about Blu-DRO/Touch DRO

[RJSakowski]

I added decoupling capacitors inside my Arduino box and they decreased the number if glitches but didn't entirely eliminate them. I also tried ferrite chocks on the power supply cable for the Arduino and on the lathe motor cord. Also tried was using a different mains circuit. My cables from the scale pickups run through flexible stainless steel conduit, grounded at both ends due to the mounting. There is about 4" of exposed cable at either end.

I should say that the Arduino circuit was breadboarded on perf board using one of the Arduino shield prototypong boards and mounted in a Bakelite box so it is not the neatest design regarding suppression of interference.

With the decoupling capacitors added to the scale pickups, I haven't seen any glitches. However, the ionsidious nater of intermittants is just when you think you solved the problem, they show up. Time will tell. Fingers crossed.

 

[9t8z28]

I do not understand any of these electronics terms, abbreviations, uf’s, pf’s, electrolytics, ceramics, plastics, decouple, etc.
Can anyone explain in laymans terms what these things are that Briney Eye posted a picture of and where to get them? Decoupling Capacitors? What value do I need, if thats how they are distinguished ? I know nothing about electronics so I would need someone to recommend a particular part. You don’t have to go into detail explaining what they do, just what I need to fix the unstable jumping readouts. I already got 2 tranformers I had laying around to use on my 2 Blu-Dro units for my mill and my lathe. They helped but the problem is not gone. One is 9V and the other is 6V but they both put out 12V when tested with my digital multi meter.
Also, where do I get shielded USB cables. Everywhere I look online, they all say that they are shielded. If I have to cut the ends off and reattach the correct ends I can do that.

 

[ttabbal]

USB cables are all shielded if you buy a remotely decent one. It's entirely possible that the cables that come with the scales are not as they would not need to pass certification tests or high speed data.

Capacitors are simple enough, but are you able to solder on a PCB without damaging it? If you don't do much with electronics, you may do more harm than good trying to learn on the scales. 0.01uF/16V ceramic caps are widely used for decoupling and are available at just about any electronics supplier. Even Radio Shack kept them around.

Power supplies can read a higher voltage than expected when they are not loaded. Go with the label or test while they are powering something. Also make sure that they can supply enough current. Issues in power levels can cause all kinds of problems with electronics. If in doubt, buy a new one with the proper specs from a reputable supplier. This alone can make a huge difference. I've repaired a lot of gear just by replacing marginal power supplies.

 

[BaronJ]

Hi Guys,

Beware, it is easy to kill very low current draw electronics using unloaded linear power bricks ! One big advantage of switch mode power supplies is that they are output voltage stable, in the sense that if it says 6 volts on the label, it will be 6 volts on the output.

A linear power supply, ie one with a transformer in it could actually have an unloaded output of twice the label voltage rating.

 

[homebrewed]

A linear power supply, ie one with a transformer in it could actually have an unloaded output of twice the label voltage rating.

When referring to a linear power supply, the "linear" part of the name indicates it has a linear voltage-regulation circuit in it. An UNregulated supply will definitely have a large variation in its output that depends on the load. Plus a lot of ripple. If I bought a "linear power supply" that exhibited a large variation in its output voltage due to the load (assuming the supply isn't going into current limit), I would return it as defective.

So, although linear supplies do have transformers in them, that does NOT mean they are unregulated. It would be entirely feasible to make a linear power supply that does not have a transformer in it, but the efficiency would be pretty low; and you'd lose isolation from the AC line. And if the linear regulator failed you could end up with 120+ volts coming out of it! I'd say that's a good argument for putting a nice step-down transformer in there

 

[Briney Eye]

I do not understand any of these electronics terms, abbreviations, uf’s, pf’s, electrolytics, ceramics, plastics, decouple, etc.
Can anyone explain in laymans terms what these things are that Briney Eye posted a picture of and where to get them? Decoupling Capacitors? What value do I need, if thats how they are distinguished ? I know nothing about electronics so I would need someone to recommend a particular part. You don’t have to go into detail explaining what they do, just what I need to fix the unstable jumping readouts. I already got 2 tranformers I had laying around to use on my 2 Blu-Dro units for my mill and my lathe. They helped but the problem is not gone. One is 9V and the other is 6V but they both put out 12V when tested with my digital multi meter.
Also, where do I get shielded USB cables. Everywhere I look online, they all say that they are shielded. If I have to cut the ends off and reattach the correct ends I can do that.

Capacitance is a measure of electrical charge, expressed in farads. A microfarad is abbreviated uf (or uF), a nanofarad is nf, a picofarad is pf. Ceramic capacitors are two-terminal devices made like a layer cake of "interdigitated" (like lacing your fingers together) conductive and insulating layers. The insulator is a ceramic material. Electrolytics are typically wound up like a jelly roll. A layer of foil is wound up together with a layer of insulator. The insulator can be made of different things. There is also some kind of solid, liquid or gel electrolyte in there, but if you care you can google it.

Decoupling refers to providing a low-impedance reservoir of charge (generally a capacitor or capacitors) close to a component. It "filters" the power and takes the noise out (it's really more complicated than that, but filtering is a good enough analogy).

In the picture I put up, the round, reddish thing with two wires is a ceramic capacitor. I had it in my stash, and probably bought it from Radio Shack twenty years ago. Here are some other ceramic shapes. They generally don't care which direction they're installed:

Here's what electrolytics look like. They have polarity markings because they care which direction they're put in:

If you're going to do this, for simplicity's sake, I would recommend buying a kit from Sparkfun. Since you have no electronics experience, open one of your read heads and post an extreme closeup of the circuit board inside. We need to be able to read the silkscreen to tell you where to install the capacitor. You will need a small soldering iron and some electronic solder. Install one of the 10nf (nanofarad) ceramic capacitors like the first picture between "ground" and power (might be labeled GND and VCC).

Or find a friend who understands this stuff to help you. Don't worry about your cables until you've tried this first. Best of luck.

 

[9t8z28]

Thank you very much for taking the time to explain all of this in great detail. It is much appreciated.
I will take the cover off of one of my iGaging read heads and post a picture.
When selecting a 10nf ceramic capacitor do I have to be concerned with the voltage ? Just doing a quick search on Ebay shows different voltages. Some are 100V, 103V, 1,000V and so on.
Yes I am capable of soldering small parts. I have made some repairs to some of my car audio Kenwood head units and Amps, replaced and resoldered a CD spindle motor, replaced ribbon cables, soldered small wires to a board to fix broken RCA cables. As I said previously, I don’t really know much about electronics but if I know what the problem is and someone has diagnosed it, I can repair it.

Capacitance is a measure of electrical charge, expressed in farads. A microfarad is abbreviated uf (or uF), a nanofarad is nf, a picofarad is pf. Ceramic capacitors are two-terminal devices made like a layer cake of "interdigitated" (like lacing your fingers together) conductive and insulating layers. The insulator is a ceramic material. Electrolytics are typically wound up like a jelly roll. A layer of foil is wound up together with a layer of insulator. The insulator can be made of different things. There is also some kind of solid, liquid or gel electrolyte in there, but if you care you can google it.

Decoupling refers to providing a low-impedance reservoir of charge (generally a capacitor or capacitors) close to a component. It "filters" the power and takes the noise out (it's really more complicated than that, but filtering is a good enough analogy).

In the picture I put up, the round, reddish thing with two wires is a ceramic capacitor. I had it in my stash, and probably bought it from Radio Shack twenty years ago. Here are some other ceramic shapes. They generally don't care which direction they're installed:

Here's what electrolytics look like. They have polarity markings because they care which direction they're put in:

If you're going to do this, for simplicity's sake, I would recommend buying a kit from Sparkfun. Since you have no electronics experience, open one of your read heads and post an extreme closeup of the circuit board inside. We need to be able to read the silkscreen to tell you where to install the capacitor. You will need a small soldering iron and some electronic solder. Install one of the 10nf (nanofarad) ceramic capacitors like the first picture between "ground" and power (might be labeled GND and VCC).

Or find a friend who understands this stuff to help you. Don't worry about your cables until you've tried this first. Best of luck.

 

[RJSakowski]

Thank you very much for taking the time to explain all of this in great detail. It is much appreciated.
I will take the cover off of one of my iGaging read heads and post a picture.
When selecting a 10nf ceramic capacitor do I have to be concerned with the voltage ? Just doing a quick search on Ebay shows different voltages. Some are 100V, 103V, 1,000V and so on.
Yes I am capable of soldering small parts. I have made some repairs to some of my car audio Kenwood head units and Amps, replaced and resoldered a CD spindle motor, replaced ribbon cables, soldered small wires to a board to fix broken RCA cables. As I said previously, I don’t really know much about electronics but if I know what the problem is and someone has diagnosed it, I can repair it.

My iGaging pickups are running on about 3.5 volts so any ceramic disk capacitor should work. It doesn't hurt to have a higher voltage rating. The capacitor will be physically larger than the same value in a lower voltage rating.

 

[9t8z28]

Let me make sure I’m understanding this, you’re saying that it doesn’t matter what nf value or voltage value ceramic disk capacitor I use, as long as the voltage rating of the capacitor is higher than the voltage that is supplied to the read head? If I am understanding that correctly that means that these 100V ceramic disk capacitors will work just fine.

I am using Blu-Dro controllers and I am unaware of the voltage that is supplied to the read heads. I can only assume that its 3.5V which is the same as Yuri’s Arduino board.

My iGaging pickups are running on about 3.5 volts so any ceramic disk capacitor should work. It doesn't hurt to have a higher voltage rating. The capacitor will be physically larger than the same value in a lower voltage rating.

 

[RJSakowski]

Let me make sure I’m understanding this, you’re saying that it doesn’t matter what nf value or voltage value ceramic disk capacitor I use, as long as the voltage rating of the capacitor is higher than the voltage that is supplied to the read head? If I am understanding that correctly that means that these 100V ceramic disk capacitors will work just fine.

I am using Blu-Dro controllers and I am unaware of the voltage that is supplied to the read heads. I can only assume that its 3.5V which is the same as Yuri’s Arduino board.

It does matter what the capacitance (nf, mfd, etc.) is but it isn't critical. The filtering (noise suppression) increases with increasing capacitance but generally, using a capacitor half the value or twice the value won't make much difference. As long as the voltage rating exceed the voltage in the circuit, any capacitor will be fine.

Picking the right capacitance is a bit of a shotgun approach anyway, because we really have no idea what the frequency and magitude of the interference is. Most of the time the interference will be quite small in magnitude and most likely fairly high frequency so it doesen't take a huge capacitance to snub it. Typical capacitances run from .001 to .1 mfd (1 to 100 nf). I used .05 mfd in my iGaging because it was the largest value that I had handy.