MC_Home
Calibration of the axis (referencing) is carried out with the function block MC_Home.
The reference mode is set in the TwinCAT SystemManager in the encoder Incremental dialog (also see Reference mode for incremental encoder).
VAR_INPUT
VAR_INPUT
Execute : BOOL;
Position : LREAL;
bCalibrationCam : BOOL;
END_VAR
Execute : The command is executed with rising edge.
Position : Position when the reference cam is reached. The constant DEFAULT_HOME_POSITION can be used to make use of the Calibration Value which is defined in the TwinCAT SystemManger.
bCalibrationCam : Reference cam.
VAR_OUTPUT
VAR_OUTPUT
Done : BOOL;
Error : BOOL;
ErrorID : UDINT;
END_VAR
Done : Becomes TRUE once referencing is complete.
CommandAborted : Becomes TRUE, if the command could not be fully executed. The reason may be an error, a stop or a superimposed travel command.
Error: Becomes TRUE, as soon as an error occurs.
ErrorID : Supplies the error number when the Error output is set.
VAR_IN_OUT
VAR_IN_OUT
Axis : NCTOPLC_AXLESTRUCT;
AxisOut : PLCTONC_AXLESTRUCT;
END_VAR
Axis : Axis structure.
AxisOut : Axis structure from PLC to NC.
Requirements
Development environment | Target system type | PLC libraries to be linked |
|---|---|---|
TwinCAT v2.8 | PC (i386) | TcMC.Lib |
Note
The referencing process has several phases. The referencing state (calibration state) is signalled in the cyclic interface of the axis (Axis.nCalibrationState). The following diagram illustrates the individual process phases after starting of the MC_Home block.
If an axis is to be referenced without reference cam, i.e. only based on the sync pulse of the sensor, the reference cam can be simulated via the PLC program. The bCalibrationCam signal is initially activated and then cancelled, if Axis.nCalibrationState is equal or greater 4.
