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Sync write vs normal write G15 Cube servo different result

PostPosted: Sat Sep 30, 2017 8:17 pm
by enheragu
Hi there,

I'm currently working on a project and I'm trying to implement the Sync write for multiple G15 cube servo. Apparently it warps the packet as planned, but then it does not get the same result in servo. I've tried different tests:

Using normal wheel speed mode (no sync write):

In both cases the torque sent is 500 in CW (0x5 0xF4 -> 0000010111110100). The thing is that the resulting speed is different.

    Packet sent is : [ 0xFF, 0xFF, 0x1, 0x5, 0x3, 0x20, 0xF4, 0x5, 0xDD]
    Format is: Header, ID, Length, Instruction, Params, Checksum
    In this case, speed read is about 271 rpm.

Using sync write mode:

    Packet sent is : [ 0xFF, 0xFF, 0xFE, 0x7, 0x83, 0x20, 0x2, 0x1, 0xF4, 0x5, 0x5B]
    Format is: Header , ID, Length, Instruction, Address, Data_length, ID, Params, Checksum
    In this case, not sure why, speed read is about 40 rpm.

As far as I can see the packet in sync mode is consistent with the format defined in the User Manual. So, why the difference in speed?

In both cases the servo is configured in the same way, the only difference is that in the first it builds a single packet and in the second case it builds a sync one, then both are sent through the same function. In this function the packet beeing set is stored in another buffer to be printed afterwards.

Anyone sees the problem?

Thank you in advance.