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PS:
Modbus command:
Query message
DA
01
Response message
DA
01
DA: Device Address-0x01
FC: Function Code-0x0F=>Write multi-DO
SA(Hi): Start Address(Hi byte)-0x00
SA(Lo): Start Address(Lo byte)-0x00
NO(Hi): No. Of points (Hi byte)-0x00
NO(Lo): No. Of points (Lo byte)-0x10
BC: Byte Count-0x02
4.8.2 Receiving data from the Profibus master device
--Send Command to read DI of the GW-7552-B
The user needs to input command ("01 02 00 00 00 10") in MBRTU and click
<Send Command> button to send Modbus command: "01 02 00 00 00 10 79
C6" and then MBRTU can receive response message ("01 02 02 00 00 B9
B8"). In this message, the user can know the value of DI0 & DI1 is "0" in the
GW-7552-B.
--Send output data to write DI of the GW-7552-B by the Profibus master
The user needs to set "0xFE" & "0xDC" in byte 3 & byte 4 of output data
area in the variable table of the configuration program "Step 7 Manager" and
GW-7552-B / GW-7552-M PROFIBUS/MODBUS GATEWAY User Manual (Version 1.60, May/2017) PAGE: 49
SA
SA
FC
(Hi)
(Lo)
0F
00
00
SA
SA
FC
(Hi)
(Lo)
0F
00
00
NO
NO
BC
(Hi)
(Lo)
00
10
02
NO
NO
(Hi)
(Lo)
00
10
54
DATA
FF
FF
CRC
check
07
CRC
check
E3
90
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