Hello Guest it is October 13, 2019, 07:16:38 PM

Author Topic: CS Labs CSMIO/P-A  (Read 16559 times)

0 Members and 1 Guest are viewing this topic.

Re: CS Labs CSMIO/P-A
« Reply #290 on: August 27, 2018, 05:02:21 AM »
Hi,
I personally think the choice of names for the photodiode terminals is poor.

If the intention is to drive current through the photodiode then pin 9 should be called DI+ and the cathode common could have been called
DI- or COM- or something. The choices the Germans have made (DI- and COM+) are confusing.



Craig
« Last Edit: August 27, 2018, 05:04:54 AM by Tweakie.CNC »
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #291 on: August 27, 2018, 05:29:28 AM »
Craig if you're confused I need to throw these servos in the bin.  ;D. What chance do I have? I can build a house with my eyes closed but all this electronic terminology is as confusing as hell. 

Cheers
 
Re: CS Labs CSMIO/P-A
« Reply #292 on: August 27, 2018, 05:49:20 AM »
Hi,
these modern servos pack in so much stuff, you'll be blown away once you get the software running.

In some respects you are making life more difficult for yourself with the analogue CSMIO controller, you now have the drive closing the acceleration
and velocity loops with the CSMIO closing the position loop. With a step/direction controller the entire servo loop is closed by the drive and a number
of control features come into play which cannot happen with control split over the drive and CSMIO. I refer to indexing position and/or speed.
My Allen Bradley servo allows you to select two control modes, say step/direction position mode and analogue velocity mode, either of which can be selected
by asserting one digital input. Really handy, assert one input and my servo turns from a free running voltage controlled motor to a high torque indexable
servo with a resolution of 5 arc min.

Anyway the chances are these servos will be in the family for many years and no doubt you will get to sample how they do with an open loop step/direction control.

Craig
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #293 on: August 27, 2018, 11:36:00 AM »
Hi Craig

With reference using a 5k resistor from the CSMIO to the servo input. I can't find anything in the manual that says it has a current limiter in the servo input circuit. Can only see the information on the attached screenshot. Should I wire in a 5k resistor on that 24v line from CSMIO to the Input?

Cheers

 
Re: CS Labs CSMIO/P-A
« Reply #294 on: August 27, 2018, 02:47:27 PM »
Hi.
no. It looks like the manufacturer has included a current limit resistor in the input circuit. The pic is from one you
posted earlier.

Craig
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #295 on: August 27, 2018, 03:00:31 PM »
Hi,
as I say the manufacturer has thought of everything. The current limit resistor is built in and there is an antiparallel diode over the photodiode
to prevent excess reverse bias destroying the photodiode.

Photodiodes and LEDs are like regular diodes, they conduct current in one direction but block current in the reverse direction. The problem is they
can usually block on 5V or less in the reverse direction. If you exceed 5V reverse bias the photodiode will go into reverse breakdown. Assuming adequate
current limiting it wont destroy it but it will get hot....always a bad look for any silicon device.

To counter that shortcoming the manufacturer has put a regular diode across the photodiode so that the worst reverse bias it will experience is the
forward voltage drop of the regular diode. These two simple things have made the input circuit reasonably safe from misapplication.

Craig
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #296 on: August 27, 2018, 03:26:15 PM »
Hi Craig

Thanks nice and simple then. My next question was what are tihose two diodes for.
Connected the z axis up earlier earlier. Can jog at ridiculas speeds way above what I need.
Auto tuned no issues. ;D

Cheers
Re: CS Labs CSMIO/P-A
« Reply #297 on: August 27, 2018, 04:52:20 PM »
Hi,
Ridiculous speed is good! As is UNTOLD acceleration!!!

In truth fastest maximum speed is less telling than acceleration. May I suggest an experiment where yo keep upping
the acceleration in Mach until you get an overcurrent fault. That will be the true measure of what these servos can do.

Craig
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #298 on: August 28, 2018, 12:04:52 AM »
Hi Craig

Yes will give it a go when I get back on Thursday. Working away for a few days in Bournemouth. :( I need to have a read up on the encoder set up and what steps to set in mach. I believe the encoders have 1280000 pulses per revolution? If so would mean 256,000 steps per MM in mach. Seems too high to me!

Cheers
Mick     
Re: CS Labs CSMIO/P-A
« Reply #299 on: August 28, 2018, 07:34:58 AM »
Hi,
yes it is very common for encoders to have very high resolutions.

Delta 17 bit absolute encoders are 131072 count per rev.
Delta 20 bit incremental are 1048576 count per rev
Delta 24 bit multi turn can have +128 to -127 turns and 65536 count per rev within any given turn.

The encoder outputs to the CSMIO will be synthesized from the raw encoder. Thus it is very unlikely that you would choose to have such
a high resolution, way more than is practical unless you like to brag and 'do something that your mother warned you would make you go blind'.

Craig
My wife left with my best friend...
     and I miss him!