Alarm 2 or Alarm1 when mist OFF (M9) [resolved]

[rmaltais]

Hi,
On my last firmware, i use a mist on program and when i turn off (M9), before go to tool setter, i was Alarm2 or Alarm1 on IOSender. No physical trigger about my end axis. When i remove all M9 in my program, i have no problem and program run normally. Strange think...

[terjeio]

EMI? If you disconnect the mist relay/solenoid does it still happen?

[rmaltais]

I'll investigate about that. thank

[rmaltais]

When i disconnect my solenoid, nothing happen, no alarm on close mist. No alarm. Just when close it with connected, i have always Alarm 1.
When i disable hard limit, no alarm on close mist with solenoid connected.

[terjeio]

Ok, then back EMF from the solenoid is likely the cause.
How is it driven? Via a transistor? Is there a snubber diode across the coil?

[rmaltais]

Hi

Here is the schematic of the card which indicates how my solenoid is driven via EL357N and ULN2003. I don't have a diode installed between the terminals

Thank

[rmaltais]

As you suggested, I installed a diode in parallel to my coil and the problem is fixed.
Thank you again for your help.

[rmaltais]

Ok, then back EMF from the solenoid is likely the cause. How is it driven? Via a transistor? Is there a snubber diode across the coil?