RoboClaw CRC Failure?

Hi Guys,

I’m getting consistent errors when trying to read the encoders attached to a single motor on a RoboClaw 10A. I’m using packet serial mode, and I’m fairly sure everything’s wired up correctly.

My sequence of events is:

  1. Transmit command 35(Decimal) to drive motor M1 forwards using the encoder at a velocity appropriate for the motor.

  2. Transmit command 16(Decimal) to query the encoder register:

    80 10

  3. Receive response:

    00 00 00 06 80 16

The first four bytes are my encoder value (this motor is rotating very slowly - only 6 pulses in this example). The status is OK since bit 7 of byte 5 is set. The CRC is returned as 16.

Is this correct?

From the RoboClaw documentation, the CRC should be:

0x00 + 0x00 + 0x00 + 0x06 + 0x80 = 0x86 & 0x7F = 0x06

I’m pretty good at missing the obvious, so it’s likely I’m doing just that. Is the above calculation correct?

Under what circumstances could I be getting a CRC error? My wiring is very short and I’d be very surprised if this was a legitimate noise-related error since the incorrect CRC is consistent (i.e. every query).

Guidance much appreciated!


The RoboClaw is not a product we sell. Have you tried posting your questions on the BasicMicro forum?

- Ben


Tough day at the office. Too many components to think about…