HDC2450 Motor Command to zero with MiniCan control

I have an application where we are using 12 or your HDC2450 drives all being controlled via MiniCan. CanOpen had been desired but was not working correctly back in August when we were initially commissioning. The units are battery powered scenic uses for a new Brodaway musical. the show has been doing an out of town try out during which we had numerous problems with the unit, mostly do to wireless issues we believed. I have all the unit back in my facility now, and we have added RS232 connection to the drives to do more troubleshooting and tuning while running with the Can control.

In repeated testing over the weekend I found some odd behaviour that I believe could explain a lost of hte issues we were seeing that we thought were wireless related. I have attached a number of chart logs to this post for backup. It would seem that while running and for no apparent reason, the motor command will occasionally drop to 0 and then back to the correctly commanded value for no apparent reason. In some cases this will not seemingly cause a reaction at the motor, but on other occasions - especially when this happens multiple times in quick succession, the motor will react accordingly. I did a lot of logging on saturday both at the drive as well as in my PLC that is controlling the drive. At no time do I ever see my command on the PLC side show this spike. I am logging it at the CAN master right before it is sent to the drive. As you will see in the chart logs, I see it occur repeatedly on different drives, in different moves.

I tried changing the CAN buad from 250 ( what we have been running) to 125 and to 500. At 125 it seems the same and at 500 the drive seems overwhlemed and doesn't run well. I am also running a small script on the drive to deal with the MiniCan variables and I have tried chaning the wait time in it from 2 to 20 with no difference. I can;t really communicate any slower with the drive as I am passing he encoder feedback to the drive up to the PLC for the positioning control. Finally I tried higher and lower I gains ( you will see one of the log files ends in I2 = gain of 2 , all others are at 12).

I am hoping someone can help me understand this problem at the drive as it seems to have a direct impact on the overall system. When those big command spikes occur, I sometimes see big current spikes, which in turn causes problems in the motion as well potentially effecting other components.

I would also like some feedback on the tuning of the drives. These seem to run pretty well with the higher I gains. Do you have some kind of documented procedure that one can follow on the tuning, or at least some suggestions?

Thanks - Chuck

Here are the files. Did not format correctly for original post. - Chuck

This may be an issue related to the watchdog timer function. The watchdog timer in order to stay awake needs to see a command (uses the [!] command or a setcommand function in scripting) every 1 second. You can increase the timer or disable the watchdog timer.

^RWD 0

I am not sure how that could be happening. MY script is running as a loop with a WAIT 2 command at the end. It should send a set command every loop. Am I missing something in my understanding?

Perhaps upload your script and we can take a look at it. If you don't wish for this to be seen by others, please send us the script via email This email address is being protected from spambots. You need JavaScript enabled to view it.

My script, controller config, and the chart files are all in the zip file I uploaded earlier. Figured it was easier and you would need it to help troubleshoot.

My apologies.

I looked at the script and everything seems to be okay except one line, though you may have already fixed that because the script may have thrown you an error when trying to build.

setcommand(EX, TRUE)

should read

setcommand(_EX, TRUE)

Perhaps you can try increasing the watchdog timer.

setcommand(_rwd, 2000) ' set watchdog timer to 2 seconds before going to sleep if no command is given.

Your script does send a new command at very cycle. So it wouldnt be a watchdog issue.

For troubleshooting, insert a print statemement to view what speed1 and speed 2 are. The controller will always to whichever value it is commanded to go.

Beware that if you have the controller connected to the PC with Roborun active on the Run tab, you will need to click on the mute box. Othwerwise, the utility will send the slider position every 50ms and this will interfere with your script commands.

My script, controller config, and the chart files are all in the zip file I uploaded earlier. Figured it was easier and you would need it to help troubleshoot.

I will add those print statements shortly. Where will they be displayed.

I was not running in MUTE. could that be the whole issue?

Also - any feedback on the tuning based on the charts files I uploaded?

Thanks,

Chuck