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Fieldbus FAQ

Following are a series of Frequently Asked Questions relating to fieldbuses. This includes PROFINET and SERCOS.

Frequently Asked Questions

Can I commission a Profibus drive without the Profibus connected, or do I need to get the Profibus option card out of the drive?

You do not need to get the card out of the drive. You do need to deactivate the watchdog:

  • S400/S600:  in the window "Basic Setup" set "Ext. WD." to zero.
  • S300/S700:  in the window "CAN-/ Field Bus Settings" set "External Watchdog" to zero.

Can S300, S400, S600, and S700 be combined in one SERCOS ring?

Yes, without restrictions.

How can I send a speed set point by fieldbus?

How can motion tasks be started synchronously in a PROFIBUS system?

To start several drives synchronously, it can be useful to prepare the motion tasks via the bus but start them via a digital input. Refer to page Start of Motion Tasks in PROFIBUS operation.

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.

What PROFIBUS settings must I set on the drive?

The only required setting is the address.

  • For the S600 you will find it under "Basic Setup".
  • For the S300/S700 you will find it at "CAN/ Field Bus Settings".

The Profibus chip will detect the baud rate automatically. It can not be set on the drive.

Special for the S400: If the field bus address (ADDRFB) has been set to zero, the drive will be addressed via the general address that has been assigned by the S400 master.

What do I need to take note of while configuring the PROFIBUS hardware in my PLC?

Please check the PROFIBUS manual for this.

First you need to import the GSD file (koll045d.gsd). The PLC will then offer you the drive as SR6xx. You need to configure the 4AX and the 6AX.

For each group (4AX and 6AX) the input addresses must be the same as the output addresses. The addresses for the 6AX must directly follow the addresses for the 4AX.

At “Properties – DP-Slave” the watchdog should be activated.

What is the meaning of the Twin-CAT diagnostic message BoxState with S300/S700 via CAN?

SDO data mismatch at StartUp SDO-Upload Error 0x 1800, SI 1: expected value: 0x181, received value: 0x40000181 From Firmware 2.51 the behavior referring to the COB-ID has been adapted to the CAN standard.

As long as TwinCAT isn't updated, the former S300/S700 behavior can be reset by setting BUSP1=1.

When starting the Upgrade Tool USB-CAN Dongle the error message ILLHW appears.

The latest Windows operating systems (´WINDOWS Vista, 7, 8) do not support the standard USB CAN-Dongle DLL file. If the error message ILLHW (illegal hardware) appears, then, after installation, replace the file "PCAN_USB.dll" in the install folder "C:\Programs\Drive Download Utility–USB\" with the separate file "PCAN_USB.dll" from the downloaded PCAN_USB.zip archive using the Downloads tool.

Which PROFIBUS cards can be used in which amplifier?

S600 "PROFIBUS" printed on the front cover
S300/S700/S600 "PROFIBUS DP" printed on the front cover

Which companies offer fibre optic cables for SERCOS?

Lapp and Honeywell are two such companies.