I need some help. I have a used china blue & white 50 Watt (actual ~40 watt) that I just bought second-hand. While aligning the mirrors and making test cuts, I’ve recently started getting an alarm LED on my stepper motor drivers (sometimes only one axis, sometimes both, other times no alarms).
I’ve looked at the manual for the driver (2DM542-N) and this is what the LED alarm indicates: Error occurs when the motor coil current exceeds the drive’s current limit.
Can someone explain what this means and whether or not it’s software or hardware related?
FYI… the machine has NEMA 23 steppers and the driver dip switches appear to be set properly for 3A. (SW1=OFF, SW2=ON,SW3=OFF).
I don’t recall making any changes to the machine settings and I’ve tried restoring from a backup settings file (yes, I created one when I first connected the machine). Still get the alarm(s).
Any help pointing me in the right direction would be deeply appreciated.
Yes, I believe it’s a 55mm single. Based on the chart from the driver manual, would I need to change the switches? I don’t know what RMS is but I’m guessing that I’m looking for a corresponding value in the that column? Or based on the error message, does the peak value have to be higher?
Most meters display RMS values… If you measure a 50% pwm signal, although it value changes from 0 to 5V, at 50% it will read 2.5V It’s on 50% of the time and off the other 50%.
I don’t know what controller you have, but I highly doubt if you have a dsp such as a Ruida, there is an issue with it… Even though Chinese, they are commercial grade controllers.
I’ve been pretty abusive with mine and have had no issues and rarely see these fail, but like all equipment they can fail.
The controller just sends steps and directional information to the stepper motor driver…
The issue is likely either the stepper motor drivers or the motor. Wiring could be suspect.
I always suggest you open it up and gently tug on the connections. Sometimes the wires aren’t screwed down and it’s a bad connection. Only the glue they put on it is holding it…
I’d set it for an rms of the 2.2A area… This can cause the stepper motor setting, such as acceleration to vary… but you want to keep the current levels down when running.
Mine was setup from the factory using twice the current that the motor was specified to use… it was also hot to the touch… which is what lead me to investigate the issue. Mine was an OMTech China Blue 50W, which, like yours is actually in the 40W range… it measured 43W and was 880mm in length… to get 50W, it needs to be about a meter (1000mm) long…
Or, as we’ve seen, the 24 V power supply is slightly (or grossly) underqualified for the job.
If you add up all the peak motor currents, plus an amp or two for the controller / home switches / LEDs / whatever, that total will exceed the power supply’s dataplate amp spec by a considerable margin.
Before you tear into the hardware, replace the supply with one that’s rated for the actual current required and see if that improves the situation.
You can also reduce the stepper motor current (to the next lower value) and, if that reduces the faults, then you’re on the right track.
