GW-7552-B / GW-7552-M PROFIBUS/MODBUS GATEWAY User Manual
(Version 1.60, May/2017)
PAGE: 49
PS:
Modbus command:
Query message
DA
FC
SA
(Hi)
SA
(Lo)
NO
(Hi)
NO
(Lo)
BC
DATA
CRC
check
01
0F
00
00
00
10
02
FF
FF
E3
90
Response message
DA
FC
SA
(Hi)
SA
(Lo)
NO
(Hi)
NO
(Lo)
CRC
check
01
0F
00
00
00
10
54
07
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
