Dead 7i76 board? Could use some debugging advice

More
16 Nov 2019 18:11 #150487 by dokwine
I'm running a 5i25/7i76 setup in a CNC router. Yesterday it drilled a hole through my table as my 7i76 apparently checked out :)) Clearpath servos with no brake - you lose enable and everything sags...

Anyway, LCNC gave me this:
hm2/hm2_5i25.0: Smart serial card
hm2_5i25.0.7i76.0.0 remote error = (27) Over Current

hm2/hm2_5i25.0: Smart serial card
hm2_5i25.0.7i76.0.0 remote error = (8) Remote fault

I haven't found any error code reference numbers to guide me; doesn't seem to correspond to IO pins. No obvious problems, i.e., loose wires. The system is ~3 years old but very lightly used (home system).

Is the board dead?

Thanks

Please Log in or Create an account to join the conversation.

More
16 Nov 2019 19:44 - 16 Nov 2019 19:45 #150491 by PCW
This is reporting an external short, but it could also be a damaged output driver chip,
To debug, disconnect all field outputs and see if you still get the same error.
If you do the problem is likely in one or both of the output driver chips.
These can be replaced at Mesa

The output drivers can be damaged by switching the DC power to the field I/O section
switching large inductive loads with no flyback diode or excessive field voltage

so make sure your system has flyback diodes on inductive loads, that the field voltage never
exceeds 32V and that you only switch the AC side of the field voltage supply.
Last edit: 16 Nov 2019 19:45 by PCW.

Please Log in or Create an account to join the conversation.

More
16 Nov 2019 20:56 #150493 by dokwine
I'd been seeing the same errors with the rest of the machine powered down, but I've now also pulled all of the output connections. Same errors with an over temp error now to boot.

I only run 12v field voltage, but this summer I had installed an ATC spindle with some small pneumatic solenoids for all the air control. Thought I had read somewhere that flyback diodes weren't necessary for these, but maybe that's the culprit. I'm not switching the field voltage into the board.

Thanks for the quick help, Peter.

Ron

Please Log in or Create an account to join the conversation.

More
16 Nov 2019 21:02 #150494 by PCW
You can drive small relays and similar devices without a flyback diode but only up to 60 mA or so. Solenoids are likely to draw more than this so require flyback diodes.

I would not power the 7I76 up again to avoid further damage and send to Mesa for repair
The following user(s) said Thank You: dokwine

Please Log in or Create an account to join the conversation.

More
10 Dec 2019 17:34 #152447 by dokwine
I am remiss in replying, but everything is back up and running. Thank you Peter for your help and the quick turn on the board repair at Mesa.

Of course you were right. I checked the solenoid specs and they were pulling 120ma. The manual says use flyback diode for anything over 60 so completely my bad. Installed a fistful of 4007's and everything seems happy.

Please Log in or Create an account to join the conversation.

More
29 Nov 2021 13:49 #227895 by carl254
I recently got a similar error but only on one pin of the output blocks, the rest are operating normally , I tried switching the pin with a flyback diode installed but still got the same error. I am assuming that the chip is okay since other pins are working. What could be the problem??

Please Log in or Create an account to join the conversation.

More
29 Nov 2021 14:07 #227900 by tommylight
Check the offending pin with a DVM, if it is stuck high even when LinuxCNC is not running.

Please Log in or Create an account to join the conversation.

More
29 Nov 2021 16:26 #227923 by carl254
If high what would be the next course of action

Please Log in or Create an account to join the conversation.

More
29 Nov 2021 17:24 #227927 by tommylight
Use another one and edit the corresponding pin in .HAL.

Please Log in or Create an account to join the conversation.

More
30 Nov 2021 12:18 #227998 by carl254
Hello Tommy, after measuring the pin I found it to be stuck high even when Linux is off like you said. I am a student and still new to LinuxCNC so not very knowledgeable yet. I need to know how to reconfigure the offending pin and what new values to input(To exactly know how to go about in the linixcnc software that runs the CNC machine) . The pin with the error on the 7i76 board is for running the spindle on the CNC machine. If it is possible I would appreciate your help with some instructions on how to resolve this.

Please Log in or Create an account to join the conversation.

Moderators: PCWjmelson
Time to create page: 0.085 seconds
Powered by Kunena Forum