laser diode is slighly on during axis moves

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3 years 7 months ago - 3 years 7 months ago #267737 by ericg
Thanks for the replies, the relevant setting are
in main .hal file
setp hm2_5i25.0.pwmgen.pwm_frequency 50 (cannot remember why I selected 50 just a balance between spindle and laser requirements I think)
in laser.hal file
setp hm2_5i25.0.pwmgen.01.output-type 1
setp hm2_5i25.0.pwmgen.01.scale 100

but I do have switching PSU's, 38v and 12v ones, I'll check these out and replace with analogue ones if required.
I will also check my grounding although I have a busbar as common ground, I will also look at my shielding to see if I've missed something.
So I'm assuming from all these comments, no one thinks it's a 5i25 inherent issue?
thanks for the feedback
Last edit: 3 years 7 months ago by ericg. Reason: spelling fix

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3 years 7 months ago - 3 years 7 months ago #267739 by PCW
One thing you can do to lower HF ground currents is to put common mode chokes
( basically large ferrite beads) on the step motor leads (one bead over all 4 wires near
the driver) and the output pair (+ and -) of the step drive switching supply.

Line filters on the power supply inputs can also help.
Last edit: 3 years 7 months ago by PCW.

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3 years 7 months ago #267748 by ericg
started looking for missing/faulty earths so I was looking inside my control box with power off (of course) when I noticed the 12v switching psu for the laser, it's power on LED was blinking on every 20 seconds, that was odd so I disconnected all my cables except for the power lead and it still happened, I pulled it out to do more checking on the bench with a different power cable and it did not happen, put it back and it did happen, replaced the power lead with a heavier spare one, put everything back together and all the issues disappeared, the P2 pin was now showing 20mV and did not jump around with joint movements. Tested the old power lead and it appears fine, so other than having a lightweight cable replaced nothing else has changed.
Seems weird to me.
Thanks for everyone's input.

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3 years 7 months ago #267751 by ericg
good thoughts, re the ferrites and line filters, I think I have some of those in my boxes of electronics stuff somewhere, I'll add them for good measure.
Eric
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