Kollmorgen Support Network

I have set the PROFIBUS address correctly, but the drive always shows n04 (watchdog), or does not react to any commands from the PLC. What can be wrong?

  1. In the Setup Software please open the window “Profibus”. The baud rate is shown there. Is it set to the value that you have set in the PLC?
    No => Please check the bus wiring. The drive did not even find the baud rate. That means that even on the lowest level there is no communication. Another hint for this: The PLC CPU reports a device breakdown.
    Yes => go to 2)
  2. In this window there is a line "Input" and a line "Output". What do you see in these lines, numbers or just “yyyy”?
    "yyyy" only => Please check the hardware configuration in your PLC (see above). Possibly the drive does not receive any data. Has the watchdog been activated for the Profibus slaves?
    I see numbers => go to 3)
  3. Input/ Output are from the PLC's point of view, i.e. the line "output" shows data from the PLC to the drive. What do you see in line "input" in PZD 5?
    Zeroes only => Has the Software- Enable been set via Profibus? At FB10 this is the input SW_Enable.
    Yes, but there are zeroes anyway. |=> Communication works ok, but the drive has not yet been initialized, i.e. the Profibus OPMODE has not been set yet. Using FB10 you need to write the OPMODE into the UserDB (usually 2 for positioning) and set the input Init_Drive.
    Different numbers different from zero => go to 4)
  4. In the line Input in PZD3 and PZD4 the actual position is transmitted. Due to the high resolution (20 bit per motor rev.) the last bits usually turn up and down. Do you see the last digit of PZD4 continuously changing?
    No, the numbers do not change at all (usually they are zero). => Communication works ok, but the drive has not yet been initialized, i.e. the Profibus OPMODE has not been set yet. Using FB10 you need to write the OPMODE into the UserDB (usually 2 for positioning) and set the input Init_Drive.
    Yes, the last digit of PZD4 is continuously changing. => The communication works ok, the Profibus OPMODE has been set and the process data is transmitted. Now we need to go into the details of the STW and the diffrent PZDs.