Hi Mike,

 

Power dissipation increases proportional to voltage squared. 

 

That would exceed Kanalog's 10K ohm resistor's power rating of 63mw by about 10mw.

 

You should add 2-5K ohms of series resistance to keep thinks within spec.

 

Regards

TK

 

 

 

From: michaelthomasn <michaelniksch@...>
To: DynoMotion@yahoogroups.com
Sent: Thursday, June 7, 2012 10:29 AM
Subject: [DynoMotion] Opto Inputs....again

 

Hi Tom,

The supposed 24v on the Studer grinder that I am working on is actually reading around 28v.

Is this beyond the limit of the opto inputs on the Kanalog?

I see it says 24v.....I just wonder if it will tolerate 28v.

Mike

 

Hi Mike,

 

The drift is normal.  It is almost impossible with an analog voltage to command exactly zero speed due to small offsets in Kanalog and the Amplifier as well as grounds and noise.  That is just the imperfect nature of analog vs digital.  The only real way to stop motion with the servo disabled is to also disable the amplifier.   As you noted as soon as the servo is enabled it will naturally correct for any offset and command whatever is necessary to hold the proper position.  You can try to adjust for the offset by using the OutputOffset0 parameter but you may never be able to hold it perfectly still. 

 

Regards

TK

From: Michael Niksch <michaelniksch@...>
To: "DynoMotion@yahoogroups.com" <DynoMotion@yahoogroups.com>
Sent: Thursday, June 7, 2012 6:13 PM
Subject: Re: [DynoMotion] Opto Inputs....again

 

Thanks again, Tom .

I ended up just substituting the power supply for one that I could adjust to under 24v.

I got the encoders working, estop circuit functioning, and the machine moving under the tuning screen.  

One odd thing so far with the simodrives....when I enable the simodrive before I enable an axis in in kmotion......The axis just slowly drifts off in one direction.  Once the axis is enabled, it stops moving, but you can see the dac output applying a constant small voltage as if it was fighting the axis' tendency to wander toward one direction.

Any ideas about that?

I could enable them at the same time in my init.c......but the constant voltage in one direction seems odd.  I expected it to dither back and forth somewhat.

Mike

On Jun 7, 2012, at 11:49 AM, Tom Kerekes <tk@...> wrote:

 

Hi Mike,

 

Power dissipation increases proportional to voltage squared. 

 

That would exceed Kanalog's 10K ohm resistor's power rating of 63mw by about 10mw.

 

You should add 2-5K ohms of series resistance to keep thinks within spec.

 

Regards

TK

 

 

 

From: michaelthomasn <michaelniksch@...>
To: DynoMotion@yahoogroups.com
Sent: Thursday, June 7, 2012 10:29 AM
Subject: [DynoMotion] Opto Inputs....again

 

Hi Tom,

The supposed 24v on the Studer grinder that I am working on is actually reading around 28v.

Is this beyond the limit of the opto inputs on the Kanalog?

I see it says 24v.....I just wonder if it will tolerate 28v.

Mike