Grundfos CIU 200 - CIM 200 Modbus RTU Setup; Setting the Modbus Transmission Speed

5. CIM 200 Modbus RTU setup
1 2 3 4 5 6 7
8
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TM041697
CIM 200 Modbus module
Pos. Designation Description
1 D1
Modbus terminal D1
(positive data signal)
2 D0
Modbus terminal D0
(negative data signal)
3 Common/GND Modbus terminal Common and GND
4 SW1/SW2
On and off switches for termination
resistor
5 SW3/SW4/SW5
Switches for selection of Modbus parity
and transmission speed
6 LED1
Red and green status LED for Modbus
communication
7 LED2
Red and green status LED for internal
communication between CIM/CIU 200
and the E pump
8 SW6
Hexadecimal rotary switch for setting
the Modbus address, four most
significant bits
9 SW7
Hexadecimal rotary switch for setting
the Modbus address, four least
significant bits
Use a screened, twisted-pair cable. Connect the cable screen to
protective earth at both ends.
Recommended connection
Modbus terminal
Colour code Data signal
D1-TXD1 Yellow Positive
D0-TXD0 Brown Negative
Common/GND Grey Common/GND
5.1 Setting the Modbus transmission speed
Set the transmission speed correctly before the CIM 200 Modbus
module is ready to communicate with the Modbus network. Use DIP
switches SW4 and SW5 for setting the transmission speed.
SW4
SW5
TM041710
Modbus transmission speed
DIP switch settings
Available transmission speeds in bit/s: 1200, 2400, 4800, 9600,
19200 and 38400.
The first three transmission speeds are only available via software
settings, whereas the last three are available via DIP switches.
Transmission speed [bit/s] SW4 SW5
9600 OFF ON
19200 OFF OFF
38400 ON OFF
Software-defined ON ON
Default transmission speed is 19200 bits per second, as per the
Modbus RTU standard.
Software-defined
When SW4 and SW5 are set to "software-defined", writing a value
to the holding register at address 00004 will set a new transmission
speed.
Use the following values for software-defined transmission speeds:
Software-defined transmission speed
Value to set in register
00004
1200 bit/s 0
2400 bit/s 1
4800 bit/s 2
9600 bit/s 3
19200 bit/s 4
38400 bit/s 5
This value is set to 1200 bit/s as default.
The communication interface does not support transmission speeds
above 38400 bit/s.
The software-defined transmission speed value is stored in the
communication interface and remains after a power-off.
When software-defined has been selected, then the
communication speed, parity bit, stop bits and address are
all set via specific registers.
Related information
5.2 Setting the stop bits and the parity bit
5.3 Modbus address selection
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English (GB)