Slaved axis problem

[bballish]

Hi
Im having trouble with my x axis.It has 2 stepper motors and 2 ball screws so 1 motor is a slave.What is happening is one of the motors will completly
stop when I am moving x axis.Then if i let off of the jog button and then jog again it will start working again but only briefly then it screws up again.I have tried unpluging the motor plugs and swapping the motors and the problem goes to the other motor.So it looks like the motors are good and also the cable to the motor is good.They are both using the same power supply so that isnt the problem.I have swapped out the axis drives and that didnt help.I have swapped to different pins coming out of the c10 board and changed to the coresponding motor number in config and that didnt help.Today I  moved the power supplys and any other components that were running off of a.c. out of the cabinet and 2 or 3 ft away from the d.c. side to see if I had a noise problem but that didnt help.

For the drivers Im using KL-4030 from automation technologies and 425 oz stepper motors.The breakout board is the c10 that came with the kit.
The motion controler is pmdx-411.

The Mach 4 version is 2803 the pmdx is 33.159 and firmware 42.137.

The computer Im using is a Dell optiplex 755.Intel core duo 3.0 ghz 8 gb of ram 64 bit windows 7 pro sp1 and a nvidia graphics card.
In Mach config I dont have anything setup in the input or outputs other than the e-stop button and it works fine.
I dont know what else to check or what to do and I was hoping you guys could help Me solve this before I pull the rest of my hair out.

Thanks
Blair Ballish
On the Mach config for the motors I have it at 16260.1626 counts per, 20 on velocity, .31 on acceleration

[Bob at PMDX]

I have tried unpluging the motor plugs and swapping the motors and the problem goes to the other motor.So it looks like the motors are good and also the cable to the motor is good.

Do you mean you did this:
   MotorCableA to MotorA
   MotorCableB to MotorB, and MotorB stalls
then
   MotorCableA to MotorB
   MotorCableB to MotorA, and MotorA stalls
If so, then it still might be MotorCableB that is faulty.

BUT... I suspect that you need to change the direction of one of the two motors that drive the gantry.  Usually with gantry machines, the two motors on the gantry turn in opposite directions in order to move the gantry.   If the motors are set to turn in the same direction they will try to skew the gantry (though at this point BOTH motors should stall).  When the slave motor stops moving, does it keep making noise - like the motor is trying to turn but something is keeping the shaft from turning (this is called "cogging")?  If so, then you need to change the direction of the motor that is stalling.  You can change the motor direction in one of two places:

(1) Go to the "Configuration" menu and select "Mach...".  Then click on the "Motor Config" tab.  Select the motor that is stalling (probably the slave motor) and check the "Reverse" check box down next to the acceleration (or backlash - I'm not at a PC with Mach4 right now so this is from memory).

... or ...

(2) Go to the "Configuration" menu and select "Plugins".  Then click on the "configure" button on the PMDX-SmartBOB line.  In the plug-in config, click on the "Motor Config" tab and find the motor that is the slave motor and select "reverse" for that motor.

NOTE: The "reverse" setting in both of these places reflect the same configuration item.  If you change it in one place, that change will appear in the other place as well.

You should end up with the master motor having the opposite direction setting from the slave motor.

If that doesn't solve the problem, unmount the motors from the machine so they can spin freely without worrying about the gantry mechanism.  Then try to jog the X axis and see what happens.

Bob

[bballish]

Hi
The way the motors are wired is the cable is soldered to the motor leeds and at the end of the cable I have a 4 pin plug that plugs into the control box.So to change what driver is driving witch motor I can unplug the cables and swap them around.As far as motor direction they both need to turn in the same direction.I verifed that this morning.I have run motors both on and off machine and its the same problem.With the motors off the machine the motors will start to run fine but after a while the 1 motor will slow down and run sort of jerky and then will just stop.With the motors on the machine i have been testing it in mdi.When I first start running it is fine but after a few passes back and forth it starts stalling.If I shut it down for a while (a couple hours) and turn it back on it runs fine for a little while and starts screwing up again. If I shut it down when it is scewing up and power it back up right away it is still messed up.So it might be some componet is getting hot and messing up? I dont know how to check the signals coming out of the c10 board. I have a digital multi meter but dont know what to look for. Im not saying its your pmdx-411 its just I dont know what it is. I posted on your forum because you guys seem very knowledable and you have helped me alot in the past.

Thanks

[Bob at PMDX]

First lets back up one step. Back in early Nov you were having trouble getting the motors to move even though the DROs were showing movement.  Did you get that resolved?

Presuming that you got the earlier problem resolved, has your system been running OK and then just recently started having one of the slaved motors stop working?  Or have you always had the issue with a motor stopping running?

Here is a sequence of tests to run.  Before running these tests, remove the motors from the machine and somehow label or tag the two X axis motors so you can tell them apart (for example, label them "1" and "2", or a piece of tape on the shaft of one of the motors, something other than "this motor was over there, and the other motor was over here" to identify the two motors).  Also somehow label the two KL-4030 drivers that are driving the two X axis motors.

Run these tests and let me know the results of each step.

(1) Using the current hardware and Mach4 config, run the two X axis motors until one of them fails.  Make a note of which motor failed, and which KL-4030 was driving that motor, and which 2 terminals on the C30 board were the step/dir signals for the motor that failed.

(2) Power down the motor drivers and swap the motor connectors for the two X axis motors.  For example, if "motor 1" was connected to KL-4030 #1, and "motor 2" to KL-4030 #2, then now "motor 1" connects to KL-4030 #2, and "motor 2" connects to KL-4030 #1.  Do not change anything else!  Turn on the motor power and run the motors until one of them fails.  Again make note of which motor, KL-4030 and C30 terminals were driving the motor that failed.

(3) Power off the system.  Swap the step/dir wires on the C30 board.  For example, if "motor 1" had step/dir on pins 2&3, and "motor 2" had step/dir on pins 4&5, change it so "motor 1" now uses pins 4&5, and "motor 2" now uses pins 2&3.  Do not change anything else, including Mach4 settings.  Power on the system and run the motors until one fails.  Again make note of which motor, KL-4030 and C30 terminals were driving the motor that failed.

(4) Try to run the motors again.  When one motor fails, place your fingers on the two KL-4030 drivers and see if you can tell a difference in temperature between the two.

(5) [EDIT: DO NOT DO THIS - based on info in following post that says you are already at 20us pulse width] In Mach4, disable Mach4 and go to the "Configure" menu and select "Plugins...".  Click on the "configure" button for the PMDXSmartBOB.  In our configuration dialog, click on the "Motor Config" tab and change the step pulse width to 10us instead of the 5us that I presume you have them set for.  Click on "OK" until you are at the main Mach4 screen.  Enable Mach4 and then run the motors and see if one of them still fails.

(6) Restore the previous step pulse width settings.

Bob

[bballish]

Hi Bob
Im out of town today but I will get back to it friday.As far as the problem with no motors turning I had a while back in order to fix that I had to go into the pmdx config and change the step pulse width to 20 and the motors started working.It was set to 10. But since then I have been having this problem Im having now.

Thanks

[Bob at PMDX]

As far as the problem with no motors turning I had a while back in order to fix that I had to go into the pmdx config and change the step pulse width to 20 and the motors started working.It was set to 10.

That is very suspicious.  The KL-4030 data sheet says that it needs a minimum 1.2us pulse width and can hanclle pulse rates up to 100KHz (which implies a 5us pulse width at most).  If you have to set the SmartBOB to 20us pulse widths to get it to work, something isn't right.  This makes me wonder if there is something not quite right with the C30 board's output drivers, the C30 jumper settings or the wiring between the C30 and the KL-4030 drivers, or maybe even the step/dir outputs from the PMDX-411.

I've looked back the wiring diagram that you sent us back in early Nov.  It shows the C30 "COM" terminal going to the PUL+ and DIR+ terminals, and the step/dir terminals going to the PUL- and DIR- terminals.  It also shows that there are no series resistors in the step/dir wiring between the C30 and KL-4030 drivers.  Is this still your wiring configuration?

If so, please verify that the jumpers on the C30 board are set like this:
X6 (pins 2-9 select input or output) - Set to "OUT" (jumper pins 1-2)
X7 (+5V or GND for COM terminals) - Set to pins 2-3 for +5V
X4 (pins 2-9 pull up or pull down) - OPTIONAL: remove the jumper, turn it 90 degrees and place it ONLY on the center pin of the jumper.  I *think* this should make it so there is neither a pull-up or pull-down on pins 2-9.  Since jumper X6 is set for "OUT", these signals are (or should be) always driven and do not need pull-up or pull-down resistors.

And finally (for now), when running the tests from my previous post, do the following in place of step (5):

(NEW 5) In Mach4, disable Mach4 and go to the "Configure" menu and select "Plugins...".  Click on the "configure" button for the PMDXSmartBOB.  In our configuration dialog, click on the "Motor Config" tab and change the "STEP Polarity" to "Active Low" for all motors.  Click on "OK" until you are at the main Mach4 screen.  Enable Mach4 and then run the motors and see if one of them still fails.

Bob

[bballish]

Hi Bob
I finaly got back to working on the machine and doing the items you requested. Here is a list of my results.
I verified the jumpers on c10 and there were as you stated. I removed the jumper for the pull up/down and left it off.
(1) Ran the 2 motors and after 3 or 4 minutes the motor 1 failed. It was connected to driver 1 and pins 4-5 on c10 board.

(2) Swapped the motor connectors and powered back up. After a minute or so motor 2 failed. It was connected to driver 1 and pins 4-5 on c10.

(3) Swapped the stet/dir wires on c10 board and powered back up and ran for a minute or 2 and motor 2 failed. It was connected to driver 2 on pins 2-3.

(4) Powered off and back on and ran untill it failed again. Checked the temp on drivers and motors and there was no noticeable difference. Motors and drivers were just slightly warm.

(5) Went into config for the pmdx and changed the pulse width to 10us and motors would not run at all. Changed it to 5us and motors still would not run at all.

(6) Then I changed the step polarity to active low for all the motors. And powered back up and ran motors for 30 minutes and no problems at all.

[Bob at PMDX]

(6) Then I changed the step polarity to active low for all the motors. And powered back up and ran motors for 30 minutes and no problems at all.

Good news!  I would be curious to find out if the motors still work with 10us nd 5us step pulse widths keeping the step polarity "active low".  But it sounds like you are all set.

Bob