# PM 1340GT Lathe (Next-Step) VFD Control System with Proximity Stop Update



## mksj (Oct 29, 2017)

My previous designs for VFD control systems have been posted, and I have been building pretty much the same design for about a year. I have made iterative design changes based on the requests of other hobbyists, so each system is tweaked a bit for each individual's preferences. The latest changes included a 3 way coolant selector so one can either choose continuous or intermittent (only with spindle rotation) coolant, variations on using a coolant relay/contactor/voltage source, different braking pattern selections, use of plug and socket connects for the  front control panel and proximity sensor cable, Jog Joystick, and a few other changes. The only lathe control box terminal connections are for the spindle cable and 12/24VDC power for tach, lights, etc. 

The proximity stop system which use to be bolted onto the micrometer stop is now integrated into the micrometer stop.  This makes it more compact, yet the mechanism can be removed by loosening  an Allan screw. This simplifies the mechanism, but requires me to machine the micrometer stop to install the mechanism. The proximity stop uses  an induction sensor which has been reliable and quite accurate, but there is an additional mechanical limit switch as a back-up. The proximity sensor cable requires modifications to incorporate this limit switch and both are integrated into the lathe control system.










I have been mostly recommending using the Hitachi WJ200 VFD for use with the control systems I have designed, although the new system design can be adapted to some other VFDs with a few modifications. The WJ200 VFD has proven to be reliable and works well, but I have been considering use of Yaskawa or ABB VFDs at some point in the future. VFD programming seems to be the biggest hurdle for most individuals, and different VFDs  have their quirks.  Since most of my  control systems use 5-7 VFD inputs to control different functions, and require more programming controls, many basic VFDs do not have these features and cannot be used.

The latest PM 1340GT lathes have undergone some changes in their design/wiring, which has prompted me to make further revisions in my control system designs to make it inclusive of the  PM 1340GT changes and also more universal/adaptable to other lathes. These include the ability to wire in safety interlocks for the belt cover, and in some  models a chuck shield interlock. Other lathes with manual foot brakes can also be use the new control system, but require a different brake switch and the use of an addition VFD input to issue the freewheel command.   Factory lathes with VFDs that have foot brakes often do not have a mechanical foot brake, it just acts as an E-Stop and the VFD brakes the lathe. But after having done a few lathe system installs my recommendation if your lathe does have a mechanical foot brake, I would suggest keeping it intact and have the VFD braking disabled when the mechanical foot brake is engaged.

So I have reworked my system design (I call it the Next-Step Control System) to add an extra stop relay (adds an additional safety layer), which overrides the forward/reverse relays commands when the spindle switch is in the stop position.  This is in addition to the power relay which controls both low voltage power and VFD input connections, and lockouts the VFD run commands at power up. There are a number of other interlock safety systems incorporated into the design.  The lathe control box is now too crowded for the power supply, it  is now moved to the VFD cabinet which allows the use of a coolant contactor +/- overload relay if one is using a 240VAC coolant pump. This also allows for a full sized DIN rail power supply which is easier to source.  Wiring connections have been simplified to reduce the terminals used for the internal control system connections,  a 5A schottky diode has been added at the input power terminals to prevent relay voltage spikes and also prevent damage to the control system should the power supply polarity be connected incorrectly. There have been a few other  changes,  the switch gear has mostly remained the same.  I have thought of going to a single PID controller instead of individual relays, this could be programmed for other features, but the relay control systems are reliable and relatively simple. PID controllers have much greater depth of sensor inputs and programming features, so one thought I might look into is using it to drive a cross slide stepper motor to cut tapers.  I am actually a bit surprised is that manufactures have not chucked the lathe gearboxes and replaced them with an encoder feedback drive for the  lead screw/power feed.  Probably cost less and have more flexibility, but not sure on the long term reliability (some Hardinge HLV-H lathes have this feature). Probably easier to just do a full CNC conversion.
http://www.autoartisans.com/ELS/
http://www.babinmachine.com/index.php?HLVELECLEAD

With my last  control system build I was asked to design a new 5 hole replacement control panel for the PM 1340GT control switches. I used Front Panel Express to fabricate these panels out of 2.5mm clear anodized aluminum. It would be nice to do this in house, but it is not practical for the few control systems I make. If someone is interested in the panel design file I will send it to so they can order the panel directly from Front Panel Express. They do nice work if you need custom panel work. The Next-Step Control System and panel is in the following pictures.


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## Firestopper (Oct 29, 2017)

Outstanding design and work Mark. Continually improving a product is what it all about never compromising safety features.
Great write up too, even I can understand.


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## [X]Outlaw (Oct 29, 2017)

Awesome work as usual Mark. That front panel looks gorgeous!


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## Alan H. (Oct 29, 2017)

Outstanding Mark - I am very glad I have a Jacobs Control System on my PM1340GT!  It will soon have one of those fancy cover plates as well thanks to you.


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## killswitch505 (Oct 29, 2017)

Man that’s way cool


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## ptrotter (Oct 29, 2017)

I have Mark's latest version, except for moving the 24V power supply, and it is beautiful.  The design is great and the workmanship is top notch.  I have been distracted by some other work and have not gotten my new PM1340GT completely put together yet but I have installed and tested the VFD and controls and everything works perfectly.  Thanks Mark for the great system and all of the other advice you have given me.

Paul


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## wrmiller (Oct 30, 2017)

Hey Mark, any chance that new panel will work for this rig you did for me?


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## bss1 (Oct 30, 2017)

I love the operating system Mark made for my 1340. I guess I’m spoiled and can’t imagine operating without it.  

Mark, I have the same question as Wrmiller. Will the custom face plate work on my version?  It looks like it would although the proximity override button is a little smaller than that shown above.  I am very content with what I have now, the custom plate would just take the finish detail up a notch. 

Thanks for all the great ideas and innovations!


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## mksj (Oct 30, 2017)

The new panel will fit the PM 1340GT with these control systems, but the P sensor switch would be replaced with a standard 22mm NO push button from AD, color of your choice. A full size button is easier to use, you can get unguarded or guarded switch depending on your preferences. Basically snip the wires to the mini switch and you would  directly connect the wires to the switch block or use spades. I will email you the panel designs specific to your build (Bill you have a different pot so the hole will be different), you would need to download the free CAD software from Front Panel Express to view it, just check the layout is what you want and click on the order tab and it will process it directly. I have setup all the holes to fit, but have not installed the panel. I did check it against the mounting holes on my machine. I also put a standard flat washer between the screw head and the control panel plate to prevent marring or the control panel moving when tightening the mounting screws. The panels run around $76, so reasonable for the quality and the finished look.  One can make any changes to the CAD files, but lots of colors add to the cost.
http://www.frontpanelexpress.com/downloads/front_panel_designer/?no_cache=1#downloadForm
Guarded
https://www.automationdirect.com/ad...inated_Pushbuttons_Flush_-a-_Extended/GCX1100
Unguarded
https://www.automationdirect.com/ad...inated_Pushbuttons_Flush_-a-_Extended/GCX1110

This is another panel I recently did for my Mill control pod.


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## Kamloopsendo (Oct 31, 2017)

Got my 1340GT basically in place now and power to it.  As Mark knows I spent a stupid amount of $ getting a "CSA" approved box to hold the breakers and VFD so I'm trying to finish up the connection to power without (at least at this point) spending another $1500 Canadian to purchase Marks obviously fabulous system just yet.  I've been trying to source proper VFD cable such as is recomended and without buying 100 or more feet seem unable to source it.  I currently have power run from the VFD with simple 12-3 cables in a BX housing which I know is NOT a good idea.  Not sure if in reality a 6 foot run will be an issue but I'd rather not find out if I can source the correct cable.  
I've done the basic rewire of the system in the lathe as per Mark's description but the leads to the 220 side of the 240/24V output transformer are broken (presumably by me although I don't know how) so I've ordered a new 24 volt power supply to replace the transformer (I know I could have run 110V power into the transformer as that lead is intact)
	

		
			
		

		
	








	

		
			
		

		
	
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I've attached a pic of the box I had built - it is pretty but roughly triple the cost of buying parts and building my own.  The consolation being if it explodes my insurance carrier can't say I did not play by the rules.  The addition of stop and start switches by the installer was apparently his idea - no questions asked take it or leave it and he had my VFD and braking resister.   I'll disconnect the on-off switches as they really are useless.


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## Alan H. (Oct 31, 2017)

Sounds like you would have been far better off just buying Mark's system.


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## Kamloopsendo (Oct 31, 2017)

Undoubtedly, I could have purchased Mark's system and built my own box for substantially less than what I paid for that bloody box and been way better off.  BUT, I didn't, que sera, sera.
Alex


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## lxcnc (Oct 31, 2017)

Mark, you do amazing work! I bought an Eisen 1440E single phase, swapping the motor to 3 phase.
I’ve been reading the different 1440GT builds/conversions, but not sure which plan to use. I have built three control panels using the Delta VFD-B, integrating with modbus and Mach3.
My systems aren’t as advanced, so I’d love to use your design if possible. Do you have a fee, or take donations for your plans?


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## Alan H. (Nov 2, 2017)

Here's a photo of my new front panel thanks to Mark.  It is from Mark's file and made by Front Panel Express.  It needed a tiny bit of fitting but it was no big deal and it turned out really well. 

I like it a lot and it dressed up the front of the machine.  It really augments and polishes my PM1340GT up over what I had done to the factory panel when I installed Mark's system earlier this year. 

Thanks Mark for doing all the work to get this panel designed and sourced.


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## Kamloopsendo (Nov 2, 2017)

Does look very classy Alan,  I finally weakened and am having Mark make me a new control system for my 1340GT.  I almost feel guilty using his services as he provides all of us such a great service bloody near for free (labour wise I mean).   I'm really looking forward to getting my unit up and running - it's been in the shop since late August and I just got power pulled in a week ago, couple more weeks and the lathe should be making round things. YES!
Alex


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## Alan H. (Nov 2, 2017)

Thanks Alex and congrats on ordering a Jacobs Control System.  There is a 100% probability that you will like it!  

I am betting you are planning on getting you a front panel on order as well.   You might want to check the dimensions carefully and make sure they are the same as Mark's.  Mine was about 1 mm more narrow than Mark's.   I took care of that with a 12" disc sander so it was not a big deal.


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## Kamloopsendo (Nov 3, 2017)

Alan:  Indeed I am getting that panel, looks too cool not to!   He's relocated the stop button to the end of the panel rather than the middle - other than that mine should be identical to yours.  Thanks for the comment about panel size, I'll have to look at the dimensions in the AM and let Mark know although I suspect it's ordered by now so I may have to tweak it a bit as with your, no biggie.
Alex


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## Kiwi Canuck (Nov 3, 2017)

Kamloopsendo said:


> Got my 1340GT basically in place now and power to it.  As Mark knows I spent a stupid amount of $ getting a "CSA" approved box to hold the breakers and VFD so I'm trying to finish up the connection to power without (at least at this point) spending another $1500 Canadian to purchase Marks obviously fabulous system just yet.  I've been trying to source proper VFD cable such as is recomended and without buying 100 or more feet seem unable to source it.  I currently have power run from the VFD with simple 12-3 cables in a BX housing which I know is NOT a good idea.  Not sure if in reality a 6 foot run will be an issue but I'd rather not find out if I can source the correct cable.
> I've done the basic rewire of the system in the lathe as per Mark's description but the leads to the 220 side of the 240/24V output transformer are broken (presumably by me although I don't know how) so I've ordered a new 24 volt power supply to replace the transformer (I know I could have run 110V power into the transformer as that lead is intact)
> 
> 
> ...



Alex, nice to see you making some progress there.

Did you mount the braking resistor in the VFD housing as I can't see it in there. (unless that's what I see at the very bottom of the picture)

I have been in a similar situation with being "bullied" into accepting something I didn't ask for and being charged excessively for the pleasure.

At the time it feels brutal, but it usually makes us better at being more clear in our instructions and most importantly we find better and usually less expensive ways of doing things.

Once in a while I actually find myself saying "thank you for ripping me off", I can now learn something new here and get more self sufficient.

Good call on ordering the MJSK Control System, I have been considering ordering from Mark as well.

I am capable of doing my own basic system but my workmanship is sometimes not acceptable to owner of the lathe (me) and I'm very fussy about that it looks professional so I will probably end up ordering from Mark as well.

What wire and how much are you looking for, I might have an off cut that could work for you.

Cheers,

David.


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## Kamloopsendo (Nov 3, 2017)

David:  Thanks for the thoughts with the wire but part of Mark's supply is anything I'll need so I'm good.  As far as building my own system, I did give it some thought actually as it ain't rocket science.  However, even if you simply wanted to duplicate Mark's system in Canada the cost to obtain the materials is very significantly higher than in the US.   We have as a group an OUTSTANDING opportunity to avail ourselves of a very bright guy's expertise and experience to build these systems.   For what Mark is charging me I don't believe I could build his system in Canada even with free labor.  
The Braking resistor shows better in this pic up at the top of the box.
As to being hosed on the power supply box, there is a lot of truth to what you said about a "learning" experience.  It's a long story how I ended up in that mess and mostly my own fault for not asking enough questions.   
Hell of a snowstorm up here - I just spent 2 hrs with my snowblower clearing my driveway and I'm supposed to live in a desert, at least Halloween evening was nice for the kids

Alex


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## mksj (Nov 3, 2017)

Appreciate the complements, I try to build the control systems using very good components and quality wire without going over the deep end. As mentioned, in most cases when you add minimum ordering quantity and shipping for a single system it gets expensive. This is why I often recommend going with the basic VFD system build. Time wise I put 18-20 hours into building each system, the P senor assembly I make in batches of 5 and usually spend about 10 hours making parts.   Having built quite a few different VFD systems, I have refined the building/materials and figured out what works and what doesn't.  I have been fine tuning the front panel, my stock lathe front panel is a touch wider, but the new custom Front Control Panel is now 1.0 mm narrower in width. Alex, your panel will be ordered later today, I am just double checking everything pefore I submit the order. One upside of building these systems with this new custom front control panel, is that one can use a standard 3/8" hole speed pot, which is 1/2 the price of the 22mm and more easily replaceable. Plus I mount everything in the panel, so one less thing to assemble. This along with the socket connectors has significantly decreased install time, but adds ~2 hours to my build time.


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## Kamloopsendo (Nov 3, 2017)

Mark:  The compliments are both sincere and warranted Mark.  By the way I have ordered a 22mm pot as per below - does that change the specs for the face plate.  Do you want the dimension (exact) of my existing cover plate?
Alex

*101ECX2300-5K*
Potentiometer, 5k ohm, 22mm, black. Legend plate ECX2640 purchase...
_Made in ITALY   HS: 8536.50_*EA$36.50$36.50101ECX2640*
Legend plate, plastic, black field, black background, white engra...
_Made in ITALY   HS: 8536.50_*EA$3.50$3.50*


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## Rodneyk (Oct 20, 2022)

mksj said:


> My previous designs for VFD control systems have been posted, and I have been building pretty much the same design for about a year. I have made iterative design changes based on the requests of other hobbyists, so each system is tweaked a bit for each individual's preferences. The latest changes included a 3 way coolant selector so one can either choose continuous or intermittent (only with spindle rotation) coolant, variations on using a coolant relay/contactor/voltage source, different braking pattern selections, use of plug and socket connects for the  front control panel and proximity sensor cable, Jog Joystick, and a few other changes. The only lathe control box terminal connections are for the spindle cable and 12/24VDC power for tach, lights, etc.


It has been a while, but I added Marks' system to my lathe out of the box when I bought the lathe. He actually delivered the system which detailed instructions before the lathe arrived. I was VERY intimidated about altering the machine but since I bought a 3 phase lathe, I was kind of stuck doing it and using Marks' system was the best choice I could make.
The front panel is very professionally done, and I love the fact that the jog switch is more like a joystick than a toggle switch. It has a great tactile feel. I have not installed flood coolant, but it is ready to go it I decide to someday, for now I am just using a cheap Chinese mist type coolant that works well for everything I have built so far.
Things I could still do to improve the system really come down to tweaking the VFD to brake faster.  It is pretty good now, but I am pretty sure with a little tweaking it could be better.  Currently the head stops in less than a 1/4 rotation at slow speed, but at higher speeds it takes a bit longer than I'd like. This is 100% my fault for not playing with the VFD parameters.


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## mksj (Dec 19, 2022)

Been a while since I posted any update on this system design, there have been quite a few installs of this lathe replacement control system and I have not heard of any issues or problems. I did recently revise the wiring design which is now very similar to what I build for  the 1440GT and also larger lathes like the 1440/1640 Sunmaster models. On the smaller lathes I am still using the Hitachi WJ200 VFD which has been very solid and overall the reliability has been very good. Higher end builds I had been using the Yaskawa V1000 and GA500, but there is now a 4-6 month delay in availability, as well as significant price increases. The other change I have made for the bigger lathes is to go to a 30mm proximity sensor which increases the sense range from 12mm to 15mm, they are shielded sensors so can be flush mounted. The other addition is a chip shield over the proximity sensor as random chips flying by the sensor can trigger it.

This is a recent system for a PM-1236T lathe, I had a request to add a tachometer and a spider. The spider is 1045, I core it with an annular cutter and then bore it with a carbide poring bar. There is a clamp on bracket for the tachometer sensor.






I am currently using FMX relays, these have built in suppressor diodes to prevent the voltage spikes when the coils release. I use a WEG mini contactor for the coolant circuit, by default it is wired for a 24VDC air solenoid, but can also be wired for 120/240VAC for a pump coolant suystem. I also use a schottky diode at the 24VDC voltage input, this also provides protection if someone connects the power supply wire reversed.


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