Software Corruption..?

I am building an industrial machine that is to be used in manufacturing production. It is controlled by three separate systems, two of the systems each use Seeeduino boards, the other is a single phase AC motor controlled by user input. Boths Seeeduino boards are completely independent, one drives a coil that time controls a pneumatic cylinder, the other drives a stepper motor. Both boards are powered by the same 12V power supply. All systems function perfectly until I run the AC motor. When I do so, the software on the board that controls the stepper motor somehow gets corrupted and the result is one of a few different states. Pressing the reset button or even pulling the plug and powering on again doesn’t get the board back to normal function. I have to re-load the software and things are OK again.

The board that controls the pneumatic cylinder is always completely unaffected.

There is a main box in which is mounted the main power switch, all the power supplies, the stepper driver, and the “up/down” control system for the AC motor which utilises industrial contact breakers to change direction of the motor. Both boards and the button controls for the AC motor are remotely mounted away from the main box.

On the problematic stepper driver board I run a length of standard network patch cable that carries two control signals and an earth ( each of the three consisting of a twisted pair and removing the rest ) down to the stepper driver that is mounted in the main box that the contact breakers are mounted in. The stepper driver power lines are then run back up to the stepper motor. The stepper control lines are driven from two of the analog input pins set for digital output.

As a last piece of information, I had the same problem when everything was separated and dispersed and hanging out of the machine prior to proper installation. I put it down to some possible electrical interference from the coiled pre-cut lengths of mains wire but I get the same problem when everything is installed as it should be.

Attached is a picture of the machine mid build without the main box installed, just the control panel with the two M/C’s where everything works fine. The two black buttons operate the up and down of the AC motor ( top left of machine ), the middle line controls the stepper motor ( top left of machine ) and the last line of the control panel operates the pneumatic cutter.

I don’t know why running the AC motor should affect the stepper driver M/C let alone corrupt the software.

Anyone experience similar…?


The AC motors are being controlled by contactors, this means that the start current is very high, its called direct online starting or DOL starting.
The start current would be generating voltage spikes which would be induced into adjacent wiring.
You will need to keep all the AC wiring concerned with the motor away from AC and DC and signal wiring dealing with the controllers and the equipment they control.
The controllers would best be in a shielded enclosure to minimize interference.
Make sure all earths are good connections, long wires that are not shielded, like to the servo could be the problem.

Thanks for info… new territory for me… :wink: I will try and isolate the emitter and receiver by trial and error. I suspect it is the UTP control cable that’s spiking the M/C as the other M/C is unaffected, so I’ll address that first. In addition, as well as using shielded cable all round, if I run the suspect cables, i.e. UTP, stepper and AC motor, through separate legs of the steel box frame ( see pic ) and ground the frame would this help with shielding…?

Thanks again.

if I run the suspect cables, i.e. UTP, stepper and AC motor, through separate legs of the steel box frame ( see pic ) and ground the frame would this help with shielding..?

Good idea, and the others as well, to isolate the problem wires.