Te-Wei Tsai added a comment - 31/Aug/21 8:32 PM After the discussion with Holger, this ticket is to find the software behavior when the rotator arrives the end-stop software limit (90/-90 degree).

Te-Wei Tsai added a comment - 31/Aug/21 9:27 PM - edited For the track  command, if the demanded position value is out of range (end-stop software limit), the command will be illegal: https://github.com/lsst-ts/ts_rotator_controller/blob/develop/src/commanding.c#L261-L281 // tracking and slewing mode command case TRACK_VEL_CMD: if (!(isEnabled(state1))) { // printf("Rejected: must be enabled state\n"); // // 11OCT gLastCommandIllegal = 1; break ; } // check for the target position being beyond allowed // position. if ((cmdMsg.param2 > rotatorCommands_signal.Parameters_upperPosLimit_deg) || (cmdMsg.param2 < rotatorCommands_signal.Parameters_lowerPosLimit_deg)) { syslog(LOG_ERR, "TRACK_VEL target position exceeds range" ); rotatorCommands_signal.Parameters_trackVel_rate_degPerSec = 0.0; LsstCmdSet[2] = 0.0; gLastCommandIllegal = 1; break ; } This is the similar case of POSITIONSET command.

Te-Wei Tsai added a comment - 31/Aug/21 9:35 PM - edited In the simulink model, there is a subsystem: Limit_check_Bias_Calc . The positionFault  will be 1 if the rotator angle is out of range. This will write into rotatorTelemetry_signal.Flags_positionFeedbackFault . This will trigger the errorIsTrue in the state machine: If the system is in the Enabled  state and errorIsTrue is 1, the system will transition to the ControlledStopping state and stop the rotator's movement.  

Te-Wei Tsai added a comment - 31/Aug/21 9:47 PM - edited Based on the implementation, the rotator CSC is using the same mechanism of end-stop limit when the CCW falls behind. Both of them make use of the trigger of errorIsTrue = 1.0 and put the system into the ControlledStopping  sub-state. Thanks!

Holger Drass added a comment - 31/Aug/21 11:28 PM Thanks, Te-Wei. This answers the question.