Trouble setting up Acorn with DG4S-16035 Drivers

[david.cuban]

I am having trouble setting up my CNC components. I am using a DG4s-16035 driver as I need high voltage for my setup. I have tried to follow suggestions on the acorn setup schematics but since the DG4S is not listed as an option in the schematics or the CNC12 setup wizard I have been trying my best on my own but with no success. I am using this system to replace a broken Centroid M15 system on an old atrump machine. I am using the encoders and the power distribution electronic from the original system but replacing the drivers and using the Acorn device.

If anyone has any advice or hookup schematics for these drivers your help would be greatly appreciated.

Thanks
David

[Jr914]

I am using the DGS4 on my lathe. What problems are you having?
john

[Muzzer]

Me too. I have 3 of these on my Shizuoka milling machine. Work fine. I have a 100VAC transformer and bridge rectifier / bus cap for the power side and the step / dir signals are completely conventional. You need to connect the motor encoders to the DG4S servo drives and get them running before you get them near the Acorn.

You need to use the CNCdrives "servoconfigurator3" software to set up the PID parameters, just like any servo system but I found it fairly straightforward. http://www.cncdrive.com/Servoconfig3.html If you want some starting values for the tuning parameters, we can help. It's also useful for checking you have the encoders connected up properly so they work before you go to the next stage.

Did you buy the "USB programming stick"? http://www.cncdrive.com/downloads/USB_p ... manual.pdf You need that to run the programming software.

Murray

[david.cuban]

Thank you for the suggestions. I was not aware of the normal setup procedure for the drives and after following the instructions I was able to get the drive functioning and actuating the different axes. My next question is about the PID tuning parameters. I currently have the values that are preset with the configuration software but don't know how to tune it beyond that.

The motors I am using are:
SEM
Type: MTS30F4-52 No. W36468
C. Stall Current: 3.4 A
Max: 2700 RPM 140V 18A
Tacho V/KRPM IP 54 IC 400
M97-77299
Ferrite Brushed DC Servomotor

My encoders have 2000 steps per revolution.

1 revolution of the motor is 0.1 in.

My next question is how to setup the cnc12 setup wizard. I have 2 limit switches per axis and only see an option for 1 limit switch per axis. Should I just use one limit switch and a software distance limit?

Thanks,
David

[cnckeith]

in the Wizard i/o drop down.. assign an input to "home all" and assign another input as "limit all" and you can connect home switches to one input and the limit switches to the other input. and you should always use software limits even if you have a hard limit switch on the opposite side of travel of the home switch.. see hook up schematics on how to wire home all and limit all

[david.cuban]

Thank you for the response Keith. I have wired everything up and set an input as "home all" but cannot find a value in the dropdown options for "limit all". I moved on to try to jog the axes with the cnc12 program but when I try to use the "home by switch" option the text panel tells me it is "moving" then it says I have a "Driver Fault". I switched the homing options to "simple home" and restarted so after the axes zeroed I attempted to jog the all of the axes but none moved. The DRO read a change in position for each axis but the axes themselves would not move. I tried to move each axis by hand and found that all were being held in position by the drives. I don't know what the problem could be as no faults are detected but there is no response by the drives? Is it possible I miss-wired the DG4S drives? Do I need to wire the error and reset lines from the drivers to the acorn in order to make the system work? If so which terminals need to be wired to the error and reset lines and how do I set them up with the cnc wizard?

I appreciate any help you can offer.

Thank you,
David

[Muzzer]

Dunno if you got anywhere with the PID tuning but I'm away from home and can't help much with the settings other than give you a bit of an idea how to get the P, I & D values in the right region. It's a bit of a black art and requires some trial and error.

There's a screen in the tuning software that allows you to send a step signal to the motor (doesn't need to be connected to a CNC controller for this). It displays the commanded position signal and also the actual position signal (back from the encoder). Obviously you want a fast response with no overshoot or final error.

The usual method is to set the I and D terms to zero, then increase the P gain until it starts to go unstable and back off "a bit". Yes, very technical. Then dial in some of the D term which will increase the speed (slope) of the response. Too much and you will overshoot and possibly go unstable. You may need to dial the P and D terms up and down against each other "a bit" to get the best response. Finally, the I term should be added to eliminate any lasting offset. If you don't do that, you will find that you will end up with poor positional accuracy. And of course, changes to the I term will affect the optimal values of the P and D terms. As I said, it's a bit of a black art. I actually ended up not that far from the default settings but with slightly different settings for the Z axis, presumably because it has less inertia.

Not sure what could be the problem with your frozen motors. If you have managed to tune the motors, it suggests that the encoders are correctly phased - but perhaps you have the enable lines configured incorrectly?

Murray

BTW - I made a note of the tuning procedure and some of the settings on my blog. You may find something helpful in there.
https://mightyshiz.blogspot.com/2017/04 ... uning.html

[martyscncgarage]

Thank you for the response Keith. I have wired everything up and set an input as "home all" but cannot find a value in the dropdown options for "limit all". I moved on to try to jog the axes with the cnc12 program but when I try to use the "home by switch" option the text panel tells me it is "moving" then it says I have a "Driver Fault". I switched the homing options to "simple home" and restarted so after the axes zeroed I attempted to jog the all of the axes but none moved. The DRO read a change in position for each axis but the axes themselves would not move. I tried to move each axis by hand and found that all were being held in position by the drives. I don't know what the problem could be as no faults are detected but there is no response by the drives? Is it possible I miss-wired the DG4S drives? Do I need to wire the error and reset lines from the drivers to the acorn in order to make the system work? If so which terminals need to be wired to the error and reset lines and how do I set them up with the cnc wizard?

I appreciate any help you can offer.

Thank you,
David

You should always post a report when asking for support.
What version of CNC12 are you using?
When you get a fault, did you look at the DG drives to see if any of them was flashing an error?
Very important you follow the DG4S drive install manual and tune the drives using their software even before you wire them up to Acorn.

Marty

[david.cuban]

Thank you again for the responses. My first thought is that I probably don't have the enable lines setup correctly. My initial guess is to wire the enable line from the Acorn to the reset and error lines from the DG4S. However, I don't see any information on the cnc setup wizard on how to set up the enable pin. I have only connected the cables but other than that do not know what the next step would be. I think this is the most likely issue with the setup. What is the proper way to wire the drives to the acorn?

To answer some questions asked earlier:

I am using CNC12 version 4.1
When the drives do not respond I get know fault detection on the Acorn side and no change in LED status lights on the DG4S side (the LED's indicate it is running properly without fault)
I have tuned the drives to reasonable values for my setup before wiring them up.

[martyscncgarage]

Thank you again for the responses. My first thought is that I probably don't have the enable lines setup correctly. My initial guess is to wire the enable line from the Acorn to the reset and error lines from the DG4S. However, I don't see any information on the cnc setup wizard on how to set up the enable pin. I have only connected the cables but other than that do not know what the next step would be. I think this is the most likely issue with the setup. What is the proper way to wire the drives to the acorn?

To answer some questions asked earlier:

I am using CNC12 version 4.1
When the drives do not respond I get know fault detection on the Acorn side and no change in LED status lights on the DG4S side (the LED's indicate it is running properly without fault)
I have tuned the drives to reasonable values for my setup before wiring them up.

You can go into the Wizard and INVERT the ENABLE output. Did you try that?