[Scott Pancheau]

I am trying to retrofit a lathe that had an Anilam control that died. I have had some help from Tom K. He has been very helpful and patient. He asked that I ask further questions on the forum - so here I am. I have a test bench set up with a 3 phase motor connected to a freq. drive and a dc servo motor and spare drive to see if I can simulate results before tearing into the lathe. Tom has helped me get to the point of being able to command the spindle motor on and off and vary the speed. I am able to enable the servo motor and it holds in an oscillating position. I cannot get movement with the dac xxx commands. I thought I needed a c program before I could use dac commands to the servo motor like I had to for the spindle motor, but Tom's last instructions were to test to see if I could command the motor speeds and direction first before doing any c program ?

Thanks,
Scott

[Thomas Zamirski]

From what I remember when setting up my system is that the console DAC command has no effect while the servo loop is enabled. Disable the axis then you should be able to manually control the axis via the DAC command.

[TomKerekes]

Hi Scott,

What kind of drives do you have? Are they +/-10V analog drives? Are they connected to Kanalog? Which DACs are they connected to?

Regards

[Scott Pancheau]

Hi Scott,

What kind of drives do you have? Are they +/-10V analog drives? Are they connected to Kanalog? Which DACs are they connected to?

Regards

Hi Tom- They are servo dynamics DC and they do use the +- 10 V analog ( pwm on original use ) The one I have connected is on DAC 0. I do have a quad encoder connected also and it does read up and down. Do I need to disconnect the encoder ?

Thanks,
Scott

[Scott Pancheau]

Thanks Thomas,
I did try that and all I get is a bump. I'll see what Tom K. says

Scott

[TomKerekes]

Hi Scott,

If you cycle power on KFLOP so that everything is default with nothing configured or enabled and enter:

DAC0=-200

on the Console Screen there should be ~1V on the DAC0 output and your motor should drive at 10%.

If the motor doesn't drive check the voltage on DAC0 with a voltmeter. If it is not 1V then there is a problem with KFLOP/Kanalog. If there is 1V then the problem is with your drive.

HTH
Regards

[Scott Pancheau]

Hi Tom,

I will try that. I am out of town til next week. Will let you know what I find. Thanks again for your help.
Scott

[Scott Pancheau]

Hi Tom,
I did as you instructed and I think things are trying to work, however I think I have a noise problem. I have a shielded cable between the motor amp and DAC 0. The shield is isolated at the amp end and connected to the dac ground at the kanalog. The voltages are correct at dac when commanded, but my servo runs all the time. It changes direction with pos and neg commands but does not stop turning unless I enable it so that the encoder is seen. Then it holds position with an oscilation of mabey a half degree. To test I disconnected the cable at the kanalog end and the motor stops. As soon as I reconnect it to the dac it starts running again even though the voltage at the dac reads 0. Can you suggest a trouble shoot method for this? I have tried to just disconnect the shield and it does not seem to make a difference.

Thanks,
Scott

[TomKerekes]

Hi Scott,

Seems strange. You never posted any information on your drives. Are they Torque mode? Velocity mode? Is there a tachometer on your motors? Is there an offset adjustment?

There might be a small offset. Can you find a DAC number where the motor stops or nearly stops?

You might command a Move of size zero and post a plot. That will show what the DAC output an encoder is doing.

Regards

[Scott Pancheau]

Hi Scott,

Seems strange. You never posted any information on your drives. Are they Torque mode? Velocity mode? Is there a tachometer on your motors? Is there an offset adjustment?

There might be a small offset. Can you find a DAC number where the motor stops or nearly stops?

You might command a Move of size zero and post a plot. That will show what the DAC output an encoder is doing.

Regards

Thanks for reply Tom.
The only info I see in the manual for the drives says they are a current source pulse width modulated DC servo amp. I previously posted brand and model. I think what I am going to do at this point is install the freq drive for spindle in the lathe and connect all kflop equip with computer to the lathe. The axis motors in the lathe do have both quad encoders and tachometers. I have been using extra equip on a test bench set up and cannot account for the problem (noise ) making the servo run when not being given a voltage signal. That means it will be awhile before I post again as I am self employed and in my busy season with real work.
Thanks again Tom.
Scott