Dynomotion

Group: DynoMotion Message: 9425 From: michaelthomasn Date: 4/24/2014
Subject: DAC Output was working.....now doesn't seem to be.
Hi Tom......It's been quite some time since I had done a retrofit of a Studer S35 grinder with Kflop and Kanalog.  Probably near 2 years.  The machine has been working fine for a long time, then the owner moved the machine and has been unable to get it to work since. 

I spent a few hours over there today, and I believe that the DAC outputs are not functioning.  The drives are analog Siemens SimoDrives.  If i bring up the analog screen after initializing......they show 0 volts.  The drive enables are outputting properly.  I have a feeling that I'm overlooking something obvious.  The encoders are counting fine.

The init program is unchanged from the former working edition.  I replaced it with a backup that I made from the last time I worked on it, and the result was the same.

I used a technique in the SimoDrive manual to jumper the analog inputs to see if the drive would hold, and it worked properly.  This is what lead me to believe that for some reason the DAC's are not outputting.

Any ideas about this?

Seems very odd to me since i cannot detect anything different in the setups that were working before.

Mike
Group: DynoMotion Message: 9426 From: Tom Kerekes Date: 4/24/2014
Subject: Re: DAC Output was working.....now doesn't seem to be.
Hi Mike,

The Kanalog DACs are easy to test.

#1 cycle power so KFLOP is in the default configuration with nothing enabled
#2 check if the LED on Kanalog comes on (indicates communication between KFLOP and Kanalog is working)
#3 Power off to the Amplifiers command DAC0=1024.
#4 Does DAC0 output go to -5V?

HTH
Regards
TK



Group: DynoMotion Message: 9427 From: michaelthomasn Date: 4/24/2014
Subject: Re: DAC Output was working.....now doesn't seem to be.
Thanks Tom,

That is a great help.

I will test them tomorrow.

Mike
Group: DynoMotion Message: 9428 From: michaelthomasn Date: 4/25/2014
Subject: Re: DAC Output was working.....now doesn't seem to be.
Hi Tom,

Thanks for the test procedure.  Everything tested OK.

The customer had told me many times that he had not altered anything since the move......but what he really meant to say was that he didn't alter anything that he thought would have any effect.  Ha Ha

The machine had two separate and isolated 24v power supplies.  He removed one of them and connected the remaining power supply to both circuits.

I don't understand how it happened, but the drives were receiving 48v.  Maybe it just skewed the ground reference?

Anyway...... everything was returned to operational status after restoring the isolated supplies.

Thanks again,

Mike