Author Topic: Troubleshooting help  (Read 215 times)

colelucky1

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Troubleshooting help
« on: December 23, 2018, 10:03:29 PM »
Hello there, my name is Cole. I recently bought the PMDX-424 board, and am having a bit of trouble with getting any movement at all. My plan is to use this to control my MPCNC(2 motors per axis)
The setup is a

Generic 24v power supply (Amazon)
PMDX-424
SainSmart ST-M5045 Micro stepper driver
Single NEMA 17 motor

So I have followed the set up guidesand gone through the PMDX-424 quick start guide, and feel that I have setup Mach 4 as intended. My issue is I have no motor movement. My troubleshooting goes as follows:

I am able to see that the PMDX board is showing it is sending step signals out through the step LED flashing(and as Steve suggested the DRO in Mach is moving)
I have used a multimeter on the enable pins  on both the driver and board and can see 4.98v, so thedriver is enabled. (Motor spins with ease)
Tested  both phases on the stepper motor itself (Grey(A+), Green(A-), Orange(B+), Blue(B-)
Tested the board and drivers had atleast 24v,(this is where i figured there might be a problem). The board can be from 12-36VDC, the drivers say 24-50VDC. My power supply tests at 23.2 and sometimes fluctuates. I tested this with a 40v lithium ion drill battery(Goofy I know its all I had). Everything stayed the same, board stayed on its 24v power supply, and the driver got 40v, no change.
I originally wired the COM to be Pulse and Direction positive (and subsequently changed those settings in Mach). I tried switching to COM negative or ground, and changing the STEP polarity to active low, but with no avail.

I previously used this set up with a Rambo board,  but was not very fond of the arduino flavor. So I know the stepper was just previously functioning.
For reference the stepper is a 2 amp variant, and the driver is currently set to 1 amp.

Any other info needed,or an suggestions at all are welcomed, I feel it is a simple thing I am missing, but just can not pin it down, is there anyway to test for a bad driver? Test light? Multimeter? LED's?

12strings

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Re: Troubleshooting help
« Reply #1 on: December 25, 2018, 01:40:46 AM »
If the motor "spins with ease" (I am presuming you mean turning it by hand), then the stepper driver is NOT enabled, or you have some other issue with the stepper driver and/or motor.  If the motor is wired correctly and the stepper driver is enabled,  you should not be able to turn the motor by hand.

The manual that I found for this driver is... not clear as to the polarity of the ENA signal.  But if you have the ENA+ connected to +5V and the ENA- to ground and the motor free wheels, then try disconnecting the ENA+ terminal (leave it floating) or tie it to the ENA- terminal.  If the motor STILL freewheels, something is wrong with the driver, motor, wiring or power supply.

Once you get the motor to "lock" (can't turn by hand), try jogging the motor again from Mach4.  Presuming you have the PMDX-424's "Step" terminals wired to the "PUL" terminals on the drivers it should work.

12strings

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Re: Troubleshooting help
« Reply #2 on: December 25, 2018, 01:45:15 AM »
One more thing:
Quote
I have used a multimeter on the enable pins  on both the driver and board and can see 4.98v,
Does this mean you are controlling the ENA pins on the motor drivers from a PDMX-424 output signal?  Or am I reading too much into this?

If you are controlling the ENA pins from the PMDX-424, see this:
https://faq.pmdx.com/index.php?solution_id=1008 (titled "Should I connect the "Enable" input on my motor drivers?").

colelucky1

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Re: Troubleshooting help
« Reply #3 on: December 27, 2018, 01:05:17 AM »
Thanks for your reply.
Yes, spinning by hand, and spins with ease, based on powered completely off, and no wires connected to the stepper motor at all, has the resistance as when wired to the driver and the enable pins getting their respective 5v positive and ground. I removed both wires and left them free to retest this, and the motor now has some resistance, as if one phase was shorted, but definitely not locked
I also made a small observation with this test. Upon powering up the power supply, board, and driver, the motor twitches briefly once. This only happens with the enable lines disconnected though.

I am using a 5V power and a ground from the J12 output section on the board, they are the outer pins on that section, and appear to always be outputting 5V, or at least I have not had to set them up. Do you feel that is not a good option?

Very glad you replied, just having someone with some suggestions is a  relief! I am pulling my hair out over this thing.


12strings

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Re: Troubleshooting help
« Reply #4 on: January 06, 2019, 11:46:28 PM »
Having the motors "twitch" when the driver powers on is typical.  The first issue you need to address is why there appears to be insufficient holding torque.

How much current do you have your driver configured to output?  If fact - what are ALL of your DIP switch settinsgs on the M5045 driver?

At 1 amp you may be able to turn the motor by hand.  At 2 amps, it should be near impossible.  If that is not the case, back up and verify your motor wiring.  Use a multimeter to measure the resistance between the leads that you think belong to each winding of the motor.  Disconnect the motor from the driver then measure the resistance.  You should measure low resistance (on the order of a few ohms) across one phase.  If you get high/infinite resistance either the motor winding is open or you have one wire from each winding.

Once you verify the motor wiring, remove all wires from the PUL/DIR/ENA inputs (both + and -).  Turn on your power supply to the motor driver and see if the motor has holding torque.  If so, then you don't need to connect anything to the ENA+ and ENA- terminals.  If no holding torque (spins easily), then wire +5V and GND from the PMDx-424 to the ENA+ and ENA- (yes, J12 pins 1 and 5 should be OK, pin 1 [L_5V' to ENA+ and pin 5 [Lgnd] to ENA-).  Power on the PMDX-424 and the motor driver.  Does the motor have holding torque.  If not - something is wrong with your driver or motor.  Hmmm... or 24V supply???  Measure that while powered on and make sure it remains at 24V.

colelucky1

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Re: Troubleshooting help
« Reply #5 on: March 04, 2019, 06:41:02 PM »
Awesome! I did the typical forum routine, where I found a solution, and neglected to post about what the solution was... Mainly because I am so embarrassed..

I set all of the micro stepping drivers to a low amp setting for my testing, set all of them, the exact same in fact. What I had not realized is that I managed to put the dip switches in a sequence which is not valid, so by default, no movement... And I like to call myself a logical thinker, Thank you for the feedback and input from everyone.

The next task is going to be dealing with limit switches.