MC_StepLimitSwitch

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Function Block MC_StepLimitSwitch

This Function Block performs a homing function by searching for sensor using only limit switches. (A limit switch has 1 “Off” (or “On”) area). The signal of the Limit Switches have to be written to the variables “limitSwitchPos” and “limitSwitchNeg” of the data type CMC_AXIS_IO.

Note

Inside the operation area the limit switches have to be logically FALSE and outside the borders the signal of the corresponding limit switch has to be logically TRUE.

If needed the signal from the sensor must be inverted before it is connected to an element the AXIS_IO data type

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In this case the limit switches (always active once moving part working area has been surpassed) are used for homing procedure.

  • The axis State is changed to Homing.
  • Home is commanded by user in the desired homing direction at the selected Velocity.
  • If LimitSwitch is found “On” on rising “Execute”, then the process is started in the opposite direction as specified, LimitSwitch is search for “Off” (or On depending in LimitSwitchMode setting) Edge (released), and process is restarted again in original direction. This ensures that the end conditions are always the same.
  • The time and distance limits can cause error if exceeded.
  • The direction changes only when the specified velocity is reached, this ensures acceleration and deceleration spaces are fixed.
  • This Function Block does not modify actual position.
  • This Function Block does not leave the Homing State when done.
  • This Function Block can only be used once for a homing sequence.
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See the following chapter to check if this Function Block is supported by the used axis implementation: Overview

For this Function Block there is a visualization in the Library MC_Blocks_AC500_V11.

See the following chapter for a list of available data types: Overview