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Chapter 10
Communication
The CMMB motor controller can be controlled, configured or monitored via a RS232 communication interface
(X3) using the following interface and protocol description.
10.1 RS232 wiring
If the motor controller should be controlled by a programmable logic controller (PLC) or other controllers via
the a RS485 communication interface, a RS485 to RS232 converterhas to be used.
10.1.1 Point to point connection
Figure 10-1: Communication wiring between PC (DSub 9-pin) and CMMB controller
10.1.2 Multi-point connection
The communication protocol provides network operation with a host computer operating as a master and
several CMMB controllers working as communication slaves
（
RS232_Loop_Enable(d5.15) must be set to1,
save and reboot the controller after setting). In that case the RS232 cabling must have a loop structure as
follows:
2 RX
5 GND
3TX
PC
6 4 3
X3
ID=n
6 4 3
X3
ID=2
6 4 3
X3
ID=1
…
Figure 10-2: Communication wiring between PC (DSub 9-pin) and multiple CMMB controllers
10.2 Transport protocol
RS232 communication of the CMMB motor controller strictly follows master / slave protocol. The host
computer send data to the CMMB controller. The controller checks the data regarding a checksum and the
correct ID number, processes the data and returns an answer. Default communication settings for the CMMB
motor controller are as follows:
Baud rate = 38,400 bps
Data bits = 8
Stop bits = 1
No parity check
The baud rate can be changed in RS232 BaudRate(d5.02). After changing the value it’s necessary to save
the setting and reboot the system.
The controller’s ID can be changed in Node ID(d5.02).
The transport protocol uses a telegram with a fixed length of 10 bytes.
