Communication processor and Modbus TCP
13.3 Point-to-point (PtP) communication
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
1105
Configure the receive message length parameters for this message as follows:
● n = 3 (The message length starts at byte 3.)
● Length size = 1 (The message length is defined in one byte.)
● Length m = 3 (There are three characters following the length specifier that are not
counted in the length. In the protocol of this example, the characters SD2, FCS, and ED
are not counted in the length count. The other six characters are counted in the length
count; therefore the total number of characters following the length specifier is nine.)
In this example, the characters from 5 to 10 inclusive are the characters counted by Len (n).
Configuring 3964(R) communication
13.3.4.1
Configuring the 3964(R) communication ports
You can use either of the following methods to configure the communication interfaces for
3964(R) communication:
● Use the device configuration in STEP 7 to configure the port parameters. The CPU stores
the device configuration settings and applies the settings after a power cycle.
● Use the Port_Config (Page 1110) instruction to set the port parameters. The port settings
set by the instructions are valid while the CPU is in RUN mode. The port settings revert to
the device configuration settings after a power cycle.
After adding the communication interfaces to the device configuration (Page 158), you
configure parameters for the communication interfaces by selecting one of the CMs in your
rack.
The "Properties" tab of the inspector wi
n-
dow displays the parameters of the s
e-
lected CM. Select "Port configuration" to
edit the following parameters:
Protocol: 3964(R)
Operating mode
(CM 1241 (RS422/485) module only)
Receive line initial state
(CM 1241 (RS422/485) module only)
Wire break
(CM 1241 (RS422/485) module only)
Baud rate
Parity
Data bits
Stop bits
To Next Page
Loading...
