Referencing

The stepper motor terminal enables simple referencing (homing). The digital inputs are used as cam return. If only one reference input is be used, the second input can be disabled with bit RP0.52.4 or RP0.52.5. The procedure is described in more detail in the sample below.

For meaningful referencing these registers can be re-parameterized:

  • RP0.R40: Maximum acceleration
  • RP0.R50: Emergency acceleration
  • RP0.R53: Backward referencing speed vref,b (backward means decreasing position values)
  • RP0.R54: Forward referencing speed vref,f (forward means rising position values)
  • RP0.R55: Set referencing position (low-order word)
  • RP0.R56: Set referencing position (high-order word)

Sample

The following sample illustrates referencing.

  1. Use register communication to enter the parameters in registers RP0.R40, RP0.R50, RP0.R53, RP0.R54, RP0.R55 and RP0.R56.
  2. In the control byte, set bit CB.0 to 1bin for enabling motor control.
  3. Use register communication to enter the command 0x0520 in register R7 to prepare the reference run.
  4. The process output data DataOUT must now be zero for referencing to start.
  5. The two digital inputs must not be active at the start of the homing, since they are linked through logical OR.
  6. In the control byte set bit CB.2 to 1 to start referencing. The stepper motor terminal now moves the motor in negative direction towards the limit switch with velocity vref,b (in positive direction with velocity vref,b if bit RP0.R52.0 is set).
  7. If the terminal detects that the cam is reached through a rising edge at one of the two inputs, it stops the motor with the emergency acceleration.
  8. The stepper motor terminal then moves the motor in the opposite direction with velocity vref,b.
  9. If a falling edge now appears at the controlled digital input (motor has moved away from the cam), the terminal stops the motor with the emergency acceleration.
  10. The terminal now signals successful completion of referencing by setting bit SW.3 in the status word. At the same time the referencing position configured in RP0.R55 and RP0.R56 is set as actual position.
  11. Delete bit CB.2 in the control byte to compete the referencing procedure.
  12. The terminal acknowledges this by deleting bit SW.3.