Bosch Rexroth CIMS Mk IV - Appendix C Modbus Communication Protocol Description; C.1 Communication Setup; C.2 Sensor Startup Timing; C.3 General Error Messages

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Appendix C MODBUS COMMUNICATION PROTOCOL DESCRIPTION
Connected with a PC, using a separate USB converter, following information can be read:
Sensor identification number, production date, sensor status, operating time of sensor, current
position (since last power up).
The CIMS Mk IV Sensor uses the MODBUS to read and write some information and to configure
the sensor. The MODBUS implementation follows these specifications:
[1] MODBUS over Serial Line specification and implementation guide V1.02, December 20,
2006, www.modbus.org
[2] MODBUS Application Protocol Specification V1.1b, December 28, 2006, www.modbus.org
C.1 COMMUNICATION SETUP
The following communication parameters are permanently set. Currently is it not possible to
change one of these parameters.
Communication Parameter Value
Transmission Mode RTU
Data Rate 19200 Baud
Sensor Slave Address 0xA2 (= 162dec)
Response Timeout 1000 ms
Message format 1 start bit
8 data bits, least significant bit sent first
1 bit even Parity
1 stop bit
C.2 SENSOR STARTUP TIMING
After power up the CIMS sensor starts in the Bootloader Session. After some checks the
Bootloader switches automatically to the Application Session. This checks needs up to 1 second
wait time.
After switching into Application Session the CIMS sensor send out the current measurement
signals over the RS422 line.
C.3 GENERAL ERROR MESSAGES
If the request cannot be recognized, the sensor sends an Error Message back to the master. The
following table shows all general error codes. All error codes regarding the different services are
listed in the chapter below.
To get more details about the occurred error it is possible to read out some detailed error
information by using the service Get Last Debug Detail (10h, E0FEh) as described in chapter
C.5.3.
For more information regarding Error Messages please see chapter 7 MODBUS Exception
Responses in [2].
Error CIMS -> MASTER
Byte Contents Value
0 Slave Address A2h
1 Error Function Code (Function Code + 80h) FC + 80h
2 Exception Code XXh