What are the reasons for a "Bus Error" on a PCD2.M5 or a PCD3?

FAQ #101418

A "Bus Error" (which is indicated in the history of the PCD) indicates that the firmware was not able to execute an internal command (reading from the memory bus).


In case of a "Bus Error" the firmware of the PCD2.M5xx0 or the PCD3 has experienced a serious problem because an internal command could not be executed correctly. In this situation the PCD is automatically restarting the CPU for security reasons. After the automatically executed restart the PCD will

  • go in "Halt" if no Software Watchdog is programmed in the user program
  • go in "Run" in case a Software Watchtog is programmed in the user program

The reason for a Bus error is usually a combination of a situation which is not correctly treated by the firmware. A "Bus Error" is not related to e.g. S-Bus (or a serial communication) but to the internal memory bus.

In case the reason for the Bus Error is one of the following, please update your firmware to version 1.14.23 (or 1.10.61) for a PCD2.M5xx0 or a PCD3:

  • The System Function (CSF) S.IPD.ReceiveData/S.IPD.SendData has been called with the remoteIP as undefined Text
  • An FB parameter has been provided as operand for the instruction SYSCMP
  • A "SASI OFF" has been executed on the serial port which has been used for an online connection
  • A Modbus "Init Server TCP" has been executed but the PCD does not have an IP Address configured
  • An attempt for reading data from a closed connection has been executed in Open Data Mode
  • If I/O with address over 1024 (which do not exist) are accessed (with FW 1.14.23), see FAQ 101518
  • If the Modbus TCP "Idle disconect time" is set to 0 with firmware versions older than 1.10.61 (or with a version 1.14.xx)

In case you have observed a Bus Error but the reason can not be found in the list above, please create a "diagnostic file" (from the "Online Configurator" menu "Tools") and provide this information to your local support team.



PCD3 / Mxxx

PCD2 / M5xxx

Last update: 29.05.2015 21:31

First release: 07.05.2010 09:49

Views: 42812

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