BasicMicro - Forums

Hi all,

We have a small problem getting a recently RoboClaw 2x25 working in an RC Tank. The basic problem is that after turning on, the Claw works fine until power is given to the motors for longer than a few seconds. Then the red LED starts a half second on/off blinking. Resetting will get it going again until power is applied to the motors for longer than a few seconds. Low throttle and high throttle does not change the duration until the Claw pops an error and stops working. The tank is on blocks so the tracks are running free. It does not seem to matter is the motors are going in forward or reverse.
We have noticed the Claw seems to do it more often when the motor brushes arc/spark.

Our settings are:
- DIP SW 1 and 5 are on. All others are off.
- JP1 is set on pins 1 and 2 to have the board powered from a logic battery supply. The battery is 6 volts.
- JP3's jumper has been removed so the receiver can run on it's own battery power. We have also disconnected the red power wire on the servo leads to the Claw.
- Motor input power is 18v

The radio system is a DX6i Spectrum.

We ae going to try some capacitors on the motors to see if the problem is electronic noise or voltage spikes.

Any other ideas are greatly appreciated.

Mike

We did more troubleshooting and have a little more info, though no fix yet.

By disconnecting one motor and testing the Claw operation on the other motor, we found out that the left motor will run pretty much as long as we want. After some starting and stopping though, the Claw will pop the error and stop working.
Doing the same test on the right motor resulted in what is becoming normal behavior for the Claw; it runs for a few seconds then abruptly stops with an error.

We did notice that when the Claw stops working, the motors spark horribly if running as if they were shorted across the terminals.

Figuring it might be a motor problem, we swapped out the motors for a set of lower amp draw motors. Unforetunately, that didn't fix the problem.

We even lowered the motor supply voltage to 12v just to see if that made a difference ... it didn't.

I think we are at the end of trying to figure this thing out. Unforetunately, the RoboClaw was needed for a RC tank battle this coming weekend. Unless the Claw suddenly starts working, the tank is screwed.

I kinda feel bad for recommending the RoboClaw 2x25 for the tank project. It didn't work like it should and left the tank short of power for an upcoming event. Not money well spent.

Could be the current sense is not working correctly. Could be a cold solder on the current sense resistor. Based on your description the first level over current(eg over 25amps for more than 2.5 seconds) is tripping on the one motor. The other motor sounds like the max over current is tripping when you make quick changes to the speed/direction. This one is caused by any spike over 50amps for more than 40ms.

What revision board are you using? Since it's a 2x25 I assume its the original green PCB although it could be a couple of the first Rev C Red PCB units. We've since updated the Rev C boards with more noise filtering on the current sense inputs and also increased the max and over current settings.

If there is a cold solder as I suspect on the current sense for one of the motors the only fix is to send it in for a repair/replace. If its an older rev unit it will definitely be replaced.

If it's the new Rev C board its firmware will be updated(2.1.0 is the latest firmware which has more noise filtering for max over current spikes) and we'll fix the current sense resistor. We've tested the Rev C boards with 450 watt motors(2 of them at the same time) running at 24v without a hickup.

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Basic Micro - Robotic Technology Evolved

Thank you for an answer, Nathan.

We'll get the controller turned back to you folks shortly to take a look at.

Thanks!