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Start of Motion Tasks in PROFIBUS operation

Valid for S300, S400, S600, S700

The Profibus protocol does not give any support for synchronizing the start of motion tasks. To start several drives synchronized, it can be useful to define the motion  tasks by fieldbus but start them via a digital input.

Using the setup software

  • Configure a digital input with the function 16 "FStart_Nr x" (INxMODE = 16).
  • Insert the number of a RAM motion task to the corresponding auxiliary variable "x", e.g. 194 (INxTRIG = 194).
  • Motion task 194 can be started with the digital input now. Because this is a RAM motion task, it will not be saved after switching off the amplifier. But, after switching on the drive, the EEPROM motion tasks from 1 to ... are automatically copied to the RAM motion tasks 192 to ..... That means, if you create the EEPROM motion task 3, this task will be copied to RAM motion task 194 during startup, and task 194 will always have defined data.

Using Profibus

  • Set parameter MTMUX to 194 (example). Result is, that all changes in the direct motion task will affect motion task 194 now. (MTMUX is set to 0 with every restart of the amplifier)
  • Now you can change the position, speed, ramps and motion task type of the task 194 by using the parameters O_P, O_V, O_ACC1, O_DEC1 and O_C. Task 194 can now be started with the configured digital input.

Required object numbers / PNUs 

Parameter  Function PNU Object number
MTMUX  Ã¢â‚¬Å“Pointer” 1947 347
O_P Target Position 1300 190
O_V Target Speed  1301 191
O_C Motion Task Type  1302 185
O_ACC1 Acceleration Ramp 1304 183
O_DEC1 Deceleration Ramp 1305 186