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Re: CS Labs CSMIO/P-A
« Reply #60 on: July 17, 2018, 06:09:16 PM »
Mick

Are you using Mach3 3.043.062, which is generally said to be the most stable release, with the CSMIO plugin version 2.910?

Have you removed that huge integral term Ki from the CSMIO tuning setup?

Does the motor turn or run away when both command inputs are connected to 0V? If so, it would suggest that the tacho is connected backwards (unlikely). If not, I would connect something like a pot to 10V and see if the drive and motor increase speed and run stably as to adjust the voltage from 0 to 10V. Then reverse polarity and repeat. The point here is to completely exclude the CSMIO until we are sure the drive and motor are working properly.

As a general point of principle, you might consider wiring the drive enable line directly into your emergency stop circuit, so that you are not dependent on any software device to turn off the drive in an emergency.

You have so many issues just now, it's hard to know where to start, but if it were me I'd stick to one device at a time and get it working before connecting everything in a feedback circuit, as this inter-dependence makes it harder to establish where a problem might lie.. If you feel you must use the CSMIO as a signal source, set all coefficients except Kvff to zero, as this will remove any feedback within the CSMIO and allow you to generate independent voltages as if you were using a signal generator.

Allan
« Last Edit: July 17, 2018, 06:27:33 PM by Fledermaus »
Re: CS Labs CSMIO/P-A
« Reply #61 on: July 17, 2018, 08:59:01 PM »
Hi Mick,
Allan is 100%, the CSMIO and Mach is just distracting you from getting your servo to work.

If you can't get that working properly the ALL BETS ARE OFF. You could take the CSMIO and throw it
over your shoulder for all the difference it will make.

Use a signal generator as Allan has suggested or a 9V battery and a pot.

The runaway problem sounds like the tacho is reversed polarity relative to the servo direction, change one or the
other.

With reference to the last pic I posted, the feedback gain is RV1. The instructions say that you want to have the feedback
voltage Vfb nearly equal to the command input Vin. That assures the the error, e, is small. For a small error to produce
a large current/voltage output requires a high gain G.  If you cannot get a high enough output current/voltage despite
having a maximum command input voltage THEN you'll have to back the feeback off, its your only choice.

When the manual says the feedback voltage, Vfb, should be the same as the input voltage, Vin, I think close is better than
exactly the same. If they were exactly the same then the error,e, would be zero and you would not get any output
current/voltage at all! If the input voltage is 10V, make the feedback voltage say 9V. Now try adjusting RV2 to increase
the speed.

If you are thinking about sending one or more drives for repair I'd recommend considering replacing the drive and servo
with a matching modern AC servo/drive. You could bury the original servo and drive in the garden next to the dinosaur grave.

Craig
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #62 on: July 18, 2018, 01:23:57 AM »
Hi Both

I am using version 3.043.062
Allan, I've tried the Ki on numerous different numbers from 200 up to 50000. Having all the other setting at 0. Totally agree with you about using a 10v pot its a great idea. Should I disconnect the encoder wires from the CSMIO whilst doing that or just turn it off? I presume the servo just needs to be enabled and voltage applied to the Command to get it to move?  

Craig LOL. I would love to throw them away with Mach 3 as well and buy a brand new machine. Before I can justify spending thousands on AC servos I need to give these a fair go.
Are you suggesting swapping the phases on the drive as I mentioned the other day or reversing the tacho wires?

Cheers
Mick    
Re: CS Labs CSMIO/P-A
« Reply #63 on: July 18, 2018, 01:45:19 AM »
Hi Both

Just thinking, I know its too early but the runaway first occurred when the Tach was not connected. Does this illuminate the possibility of being wired backwards? I have not rewired this, its wired as its always been. As I mentioned before could it be possible that the three-phase going into the drive needs the phases swapping to turn the motor the other way?

There used to be an ATC on this machine which was phase dependent and would only work if the phases were in a particular order.

Cheers
Mick
Re: CS Labs CSMIO/P-A
« Reply #64 on: July 18, 2018, 03:45:52 AM »
Hi,

Quote
Before I can justify spending thousands on AC servos I need to give these a fair go.
Ac servos are not free but they don't cost thousands either.

DMM 200V Off-line Servo and Drive:
750W 200V servo                   $239
230VAC Drive                         $218
3m power & encoder cables     $71

Total                                      $528

This is for a modern AC servo which will eat the old stuff alive, 16 bit encoder, direct offline power supply, a multitude of control modes including step/direction,
vastly flexible electronic gearing, acceleration and velocity limits, programmable following error, zero error, multiple error reporting modes, indexed position and
velocity and the list goes on.

Note that the servo and drive form the loop, the controller is just a plain (cheap) open loop step/direction source....no closed loop controller required!
Ye-ha! Reduce confusion and tuning problems to a mere nothing! An AC servo and drive is as easy to hook up as a stepper driver, Mach can't tell the
difference between the two.

My experience is that I bought a modern AC servo second hand but have been so impressed I wont consider the old stuff any more.

Quote
I know its too early but the runaway first occurred when the Tach was not connected. Does this illuminate the possibility of being wired backwards
No.  If it runs with the tach disconnected it just means the amp operates without feedback. Look at the last diagram that I posted.....with the tach disconnected
then the feedback voltage Vfb is zero. Therfore error, e = Vin and the output current would be Iout= Vin.G, given that G is high even a modest input voltage will cause
significant output current and the motor will speed away. That's not faulty, that's just how it works.

If the tacho is connected and there is NO input, ie Vin=0 and the motor speeds away it means that the feedback voltage is generating its own input. This
is called positive feedback and is undesirable. If you reverse EITHER the tacho OR the servo then it becomes negative feedback which is what we want.

Quote
As I mentioned before could it be possible that the three-phase going into the drive needs the phases swapping to turn the motor the other way?
No, the three phases are rectified to produce DC. Phase reversal has no effect on the DC output.
Three phase induction motors will reverse the direction of rotation if one of the phases is swapped. If the direction of rotation is important, and  it usually is
then attention to phase rotation is required. Your servos should be unaffected by phase reversal.

Quote
Totally agree with you about using a 10v pot its a great idea. Should I disconnect the encoder wires from the CSMIO whilst doing that or just turn it off?
For testing purposes 9 or 10V and a pot would be good. Whether the encoder is hooked to the CSMIO is immaterial, the CSMIO might as well be off, we don't need it,
with perhaps the exception of an enable signal, to drive the servo.

Craig
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #65 on: July 18, 2018, 06:57:29 AM »
Mike

Once you have disconnected the 2 command wired to attach your battery and pot, the CMIO cannot affect your measurements, but. The problem you could face is that if the CSMIO has to be enabled in order to enable your drive, the encoder inputs would make it throw a following error as the motor position would no longer correspond to what Mach had commanded. This would disable Mach and your drive. To eliminate this possibility enable your drive directly by connecting 24V to the enable line instead of using CSMIO. (You cannot just disable the motor in Mach as it would no longer activate your enable output.)

Craig

Fully agree. The amp simply balances the scaled tacho output against the scaled command to provide the error signal, and the actual scaling is not critical. As you say, if Mike cannot achieve full speed with 10V at the test point, the only solution, if we are to assume that the amp is otherwise working properly, is to reign back the tacho gain until full speed can be achieved. With any luck it will still be possible to adjust the command gain so that 10V, or something close, is needed at the input  to give full speed. It sounds as if the forward gain of the amp is fairly low, which could be by design or because of some component failure. We are confident that the PSU and the tacho are working correctly, but are we sure the motor itself is OK as that could conceivably be a possible cause as it contributes to the loop gain? Mike has said he could swap motors to check this.

Does the DMM support analogue input, or would its use mean replacing the CSMIO as well? I don't see much difference in having the position loop within CSMIO as opposed to within the drive. Either way it needs some adjustment to suit the machine.

Allan
« Last Edit: July 18, 2018, 07:03:22 AM by Fledermaus »
Re: CS Labs CSMIO/P-A
« Reply #66 on: July 18, 2018, 07:28:05 AM »
Hi Allan,

Quote
Does the DMM support analogue input, or would its use mean replacing the CSMIO as well?
Yes DMM servo drives support analogue input and so you could use the CSMIO but that would be crazy. Firstly many of the control features
would now no longer work because the CSMIO closes the loop, not the drive. Secondly DMM make the drive AND the servo and they are perfectly
matched to each other. You can get in there and tune if you wish but you'll have to do really well to better what DMM have done.

Quote
I don't see much difference in having the position loop within CSMIO as opposed to within the drive
That's like saying  'my Model T had a crank handle so my new sports car has to have a crank handle too'

Quote
Either way it needs some adjustment to suit the machine
You can manually tune the servo drive, although the pre-existing tuning procedures usually mean you don't have to.
Amongst the goodies is a software driven scope which allows you to visualize the adjustments you make in realtime, just so much more advanced
than the CSMIO.

Modern AC servos and drives, of which DMM is an entry level example, are so far advanced over previous methods with far greater flexibility and precision
of control that the CSMIO/A has been rendered obsolete. Do yourself a favour, don't believe me.....buy yourself an example, my preference is Allen Bradley
and prepare to be amazed.

Craig
My wife left with my best friend...
     and I miss him!
Re: CS Labs CSMIO/P-A
« Reply #67 on: July 18, 2018, 02:14:42 PM »
Hi Both

Thanks your input again.

Craig thank you for the info on the drives, cheaper than I thought but at the moment will have to persevere with the Norwin drives. I have just spent £700 on the CSMIO with the Threading module.

Right Connected a pot view a 9v Battery with the tach connected.

Adjusted RV1 until motor ceases moving.

Applied 9v via the pot and adjusted RV2 to get max speed.

Turned RV2 back to achieve approx 1000 rpm.

Check Tach voltage which was at 12.3v
Adjusted tach on P/M to 8.9 volts slightly off from the input voltage as Craig suggested.

Turned the pot down to approx 2 volts.
Checked the tach and putting out very similar voltage.

Very positive I think??
Will try connecting the controller up now and see what I get.

Allan Thanks for the tip on the enable going to the emergency stop. I will rewire that.

One thing I noticed when I was adjusting RV1 with 0V applies.  By turning the pot a significant amount makes the motor turn one way and turning the pot the other way reversed the motor. 
There was a very small millivolt signal but no matter which way the motor turned it was always negative??
Just thought I would mention it.

Can you just clarify something? We keep talking about 0v. I have a red and blue wire coming from the command high low. I have always presumed the red is positive pin 1 on the CSMIO and the blue is negative pin 14 on the CSMIO. Please educate me if needed :D

Cheers Again
Mick
Re: CS Labs CSMIO/P-A
« Reply #68 on: July 18, 2018, 04:59:50 PM »
Hi Mick

Sounds like things are making some sort of sense at last. I think the reversal you have seen could be due to a slight offset error. Although this could be ajusted using the pot on the main PCB, I wouldn't bother as the CSMIO can set the overall offset for you at the press of a button.

Are you able to get a high enough motor speed with 9V input now, and is the motor running smoothly? If speed is still limited I would be inclined (maybe with Craig's approval) to try a small adjustment of RV4 which affects loop gain. Maybe a little iteration of the settings of the 3 pots RV1, RV2, and RV4 would give you the result you require.

Quote
I have always presumed the red is positive pin 1 on the CSMIO and the blue is negative pin 14 on the CSMIO.
Yes this is the correct connection. Remember to start with Kd = Ki =Kvff = 0, and gradually increase Kv. Start with Kv = 10 and increase in steps of 10x to maybe 100000. If the motor suddenly runs away, reverse the sense of the encoder feedback and try again. If the motor begins to oscillate, reduce Kv.

It's always safest to have your eStop act directly on the drive enable as well as going independently to the CSMIO so that Mach knows what's going on. At its simplest, you could just add another contact block to your eStop switch and wire this in series with the connection to the drive enable. Some folks use a Piltz (may be incorrectly spelt!)  safety relay, but  this isn't necessary.

Craig

I doubt if we'll ever agree, but here is my final take on things. The greatest advantage of the matched servo and drive is that the drive has knowledge of all motor parameters. This is especially important in the drive's current loop, less so in the velocity loop, and less again in the position loop. Providing the drive takes care of the current and velocity loops, all that's needed to implement the position loop is encoder feedback and the calculation of a few Z transforms. I'm sure that the fast processor within the CSMIO is perfectly capable of doing that. I use Chinese Kinco drives and servos as you know, and like the DMM these are packed with features and flexibility. I am not aware that any significant features are lost by setting analogue mode and using the IP-A for the position loop. The CSMIO offers all the tuning features you need, including the scope, in its plugin. Don't just take my word for it - you only have to look at posts from folks like Hood to see that the IP-A is capable of excellent results.

Allan
« Last Edit: July 18, 2018, 05:06:47 PM by Fledermaus »
Re: CS Labs CSMIO/P-A
« Reply #69 on: July 18, 2018, 06:02:31 PM »
Hi Both

Thanks, Allan for that. Yes the RPM I have set at around 1000 which gives 5m minute. Done the test and good news and bad news. After setting the drive as described in my earlier post. Exactly the same problem. As soon as I powered the drive the motor runs flat out. Estops working though so no big deal. (Cheers for that tip) Re-booted everything and enabled the drive and the motor runs flat out again. Checked the power at pins 1 and 14 to find 10v again with no command from Mach 3.
 Changed command HI Low to pins 2 and 15 channel 1 on the CSMIO and Bingo. Everything works absolutely perfectly.  ;D ;D ::) :P

I will keep trying over the next few days to make sure it's not random fix.

Thank you very much for all your time on this and I will report back with feedback over the next few days.

Cheers
Mick