Siemens SIMATIC S7-1200 - Page 1195

Communication processor and Modbus TCP
13.5 Modbus communication
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
1195
Table 13- 71 Data types for the parameters
Parameter and type
Data type
Description
REQ IN Bool A low to high (positive edge) signal starts the operation.
(Version 2.0 only)
PORT IN Port After you install and configure a CM or CB communication device, the
port identifier appears in the parameter helper drop-list available at the
PORT box connection. The assigned CM or CB port value is the device
configuration property "hardware identifier". The port symbolic name is
assigned in the "System constants" tab of the PLC tag table.
BAUD IN UDInt Baud rate selection:
300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 76800, 115200,
all other values are invalid
PARITY IN UInt Parity selection:
• 0 – None
• 1 – Odd
• 2 – Even
FLOW_CTRL
1
IN UInt Flow control selection:
• 0 – (default) no flow control
• 1 – Hardware flow control with RTS always ON (does not apply to
RS485 ports)
• 2 – Hardware flow control with RTS switched
RTS_ON_DLY
1
IN UInt RTS ON delay selection:
• 0 – (default) No delay from RTS active until the first character of the
message is transmitted
• 1 to 65535 – Delay in milliseconds from RTS active until the first char-
acter of the message is transmitted (does not apply to RS485 ports).
RTS delays shall be applied independent of the FLOW_CTRL selec-
tion.
RTS_OFF_DLY
1
IN UInt RTS OFF delay selection:
• 0 – (default) No delay from the last character transmitted until RTS
goes inactive
• 1 to 65535 – Delay in milliseconds from the last character transmitted
until RTS goes inactive (does not apply to RS485 ports). RTS delays
shall be applied independent of the FLOW_CTRL selection.
RESP_TO
1
IN UInt Response timeout:
Time in milliseconds allowed by the Modbus_Master for the slave to re-
spond. If the slave does not respond in this time period, the Mod-
bus_Master will retry the request or terminate the request with an error
when the specified number of retries has been sent.
5 ms to 65535 ms (default value = 1000 ms).
MB_DB IN Variant A reference to the instance data block used by the Modbus_Master or
Modbus_Slave instructions. After Modbus_Master or Modbus_Slave is
placed in your program, the DB identifier appears in the parameter helper
drop-list available at the MB_DB box connection.
DONE OUT Bool
The DONE bit is TRUE for one scan, after the last request was completed
with no error. (Version 2.0 only)