Reasons for Fault Conditions

General discussion of using Roboclaw motor controllers
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ugur1yildiz
Posts: 1
Joined: Fri Feb 08, 2019 7:56 am

Reasons for Fault Conditions

Post by ugur1yildiz » Wed May 08, 2019 9:09 am

Hi,

One of my RoboClaw 2x15A V5E gives M2 Driver Fault error but M1 channel works. When I try to increase the PWM of M2 it gives M2 Fault Error. What is the probability of burned FET? Is there any other reason for Driver Fault error. What about A4940 or any other reason. Am I able to fix the problem by changing the broken-IC which I can find by your help.

I use 24VDC AC/DC power supply with a bypass diode but not voltage clamp circuit.

Thanks

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Basicmicro Support
Posts: 1164
Joined: Thu Feb 26, 2015 9:45 pm

Re: Reasons for Fault Conditions

Post by Basicmicro Support » Wed May 08, 2019 9:58 am

A Driver fault error is exactly what it says. A Mosfet driver fault. This could be the driver chip is damaged(usually by over voltage/spikes) or it could be caused by a damaged mosfet. In either case there is no way for you to fix the problem. You will need to send it in to have it repaired.

The vast majority of these failures are due to a handful of causes.

1. Using a power supply to run the Roboclaw without properly setting the maximum main battery voltage. It should be set to 1 to 2v above the power supply voltage as indicated in Motion Studio.
2. Disconnecting Battery - while running the motors( can cause negative voltage transients. It takes very little negative to damage the chips).
3. Disconnecting Battery + while slowing down the motors or back driving them significantly(eg having no path for regen). If you use a power switch you should have a diode across the switch to provide a path for regen. You should never back drive your motors a significant amount when no battery is attached. If you must be able to you should install a voltage clamp circuit as described in the user manual.
4. Least likely in my opinion is static discharge.

Ship the unit to our contact address shown on the website. Include your return address and contact information. If it is just the driver its a quick fix. If a mosfet was damaged but didn't damage the PCB its a quick fix. To prevent irreparable damage I also recommend always having an appropriately sized fuse on the battery + line.

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