Libraries
9.3 Modbus RTU library
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
483
9.3.2.3
MBUS_MSG / MB_MSG2 instruction
MBUS_MSG and MB_MSG2 have identical behavior and parameters. MBUS_MSG is for a
single Modbus RTU master. MB_MSG2 is for a second Modbus RTU master.
Table 9- 5
MBUS_MSG / MB_MSG2 instruction
LAD / FBD
STL
Description
CALL MBUS_MSG, First, Slave,
RW, Addr, Count, DataPtr,
Done, Error
CALL MB_MSG2, First, Slave,
RW, Addr, Count, DataPtr,
Done, Error
The program calls the MBUS_MSG / MB_MSG2 instruc-
tion to initiate a request to a Modbus slave and process
the response.
The MBUS_MSG / MB_MSG2 instruction initiates a master request to a Modbus slave when
both the EN input and the First inputs are ON. Sending the request, waiting for the response,
and processing the response usually requires several PLC scan times. The EN input must
be ON to enable the send request, and must remain ON until the instruction returns ON
(True) for the Done bit.
Содержание SIMATIC S7-200
Страница 30: ...Product overview 1 7 Programming software S7 200 SMART 30 System Manual V2 3 07 2017 A5E03822230 AF ...
Страница 267: ...Program instructions 7 6 Counters S7 200 SMART System Manual V2 3 07 2017 A5E03822230 AF 267 HSC modes 3 and 4 ...
Страница 394: ...Program instructions 7 18 Subroutine S7 200 SMART 394 System Manual V2 3 07 2017 A5E03822230 AF ...
Страница 425: ...Communication 8 5 PROFIBUS S7 200 SMART System Manual V2 3 07 2017 A5E03822230 AF 425 ...
Страница 786: ...Technical specifications A 11 S7 200 SMART cables S7 200 SMART 786 System Manual V2 3 07 2017 A5E03822230 AF ...
Страница 798: ...Error codes C 4 PLC fatal error codes S7 200 SMART 798 System Manual V2 3 07 2017 A5E03822230 AF ...
Страница 848: ...Ordering information F 6 Human Machine Interface devices S7 200 SMART 848 System Manual V2 3 07 2017 A5E03822230 AF ...