driver: illegal values for 'valid_fields' field in simple message binary stream

[gavanderhoorn]

Just noticed this while analysing some Wireshark captures of simple message traffic between the currently released motion_streaming_interface and a controller (exact type of the controller has no impact on the occurrence of the problem).

From the capture:

ROS-Industrial SimpleMessage, Motoman Joint Trajectory Point Full Extended (0x7e0), 288 bytes, big-endian
    Prefix
        Packet Length: 284
    Header
        ...
        Communications Type: Service Request (2)
        ...
    Body
        ...
        Group 0
            ...
            Valid Fields: 0x159e10f (Position, Time, Acceleration, Velocity)
                .... ...1 = Time         : Valid (1)
                .... ..1. = Position     : Valid (1)
                .... .1.. = Velocity     : Valid (1)
                .... 1... = Acceleration : Valid (1)
            Time: 1.08976
            ...
        ...

Note the 0x159e10f value for Valid Fields.

Only the lower four bit positions in the valid_fields field of the JOINT_TRAJ_PT_FULL_EX message type are defined, with all of the others reserved for future use (see Message Structures of the ROS-Industrial Simple Message Protocol - Defined Constants - Valid Fields).

I'm not sure if this actually leads to any problems (that would depend on how the valid_fields field is actually assigned its value), but it violates the protocol specs in any case and should be fixed.

[gavanderhoorn]

To be clear: this is a message from ROS to the controller. Messages from MotoROS are ok.

[gavanderhoorn]

Issue also does not seem to occur on single-group controllers (or at least: on ROS setups not configured to use the multi-group infrastructure in motoman_driver).

[gavanderhoorn]

More testing seems to indicate that this never happens for "the first" trajectory point.