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Leitung
English
11. Modbus communication interface
11.1. Wiring diagram
11.3. Functions implemented
Function
code
Name
Description
03 Hex
Read Hold Register
Read device parameter
04 Hex
Read Input Register
Read current value
06 Hex
Write Single Register
Write device parameter word by word
10 Hex
Write Multiple Register
Write several device parameters word by word
Function
code
Name Sub-function
Description
08 Hex
Return Query Dat
00
Send the received message back
08 Hex
Restart Communications 01
Restart communication
08 Hex
Force Listen Only Mode
04
Switch to listen-only mode
Fig. 25:
Control unit
120 Ohm
Place Jumper K 1 for the last
device on the bus
Signal line B with 10 kOhm
to GND
Signal line A with 10 kOhm to
+24 V
11.2. Interface information
The device works as a Modbus RTU slave. The interface configuration is 8N1, 9600Baud, slave
address 1. The address and the baud rate can be set via parameters P7 and P8. As bus line is recom-
mended a twisted pair data cable with 120 Ohm impedance.
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