Siemens SIMATIC S7-300 Reference Manual page 60

Basic instructions
MODBUS (RTU)
S7-300/400: Commands for ET200SP CM PtP
✔
Configure port on the PtP module for Modbus
RTU
✔ ✔ ✔ ✔
Configure communications module for
Modbus
✔
Communicate as Modbus master via PtP port
✔ ✔ ✔ ✔
Communicate as Modbus master
✔
Communicate as Modbus slave via PtP port
✔ ✔ ✔ ✔
Communicate as Modbus slave
PtP link: CP 340
✔ ✔
Receive data
✔ ✔
Send data
✔ ✔
Output message text with up to 4 tags on
printer
✔ ✔
Delete receive buffer
✔ ✔
Read accompanying signals on the RS-232C
interface
✔ ✔
Read accompanying signals on the RS-232C
interface
A5E33285102-AB
Extended instructions
Description
Technology
STL
LAD / FBD
(not S7-1200)
MB_COMM_LOAD
Modbus_Comm_Load
MB_MASTER
Modbus_Master
MB_SLAVE
Modbus_Slave
P_RCV
P_SEND
P_PRINT
P_REST
V24_STAT_340
V24_SET_340
Communication
SCL
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