Siemens SIMATIC ET 200AL, System Manual

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Communication
148
Function Manual, 05/2021, A5E03735815-AJ
Properties of procedure 3964 (R)
• When the data is sent, control characters are added (start, end and block check
characters). Make sure that these control characters are not included as data in the frame.
• Connection establishment and termination makes use of control characters.
• If transfer errors occur, data transfer is automatically repeated.
Data exchange using Freeport or 3964 (R) communication
The data to be sent is stored in the user program of the corresponding CPU in data blocks
(send buffer). A receive buffer is available on the communications module for the received
data. Check the properties of the receive buffer and adapt them if necessary. You must create
a data block for receiving in the CPU.
In the user program of the CPU, the "Send_P2P" and "Receive_P2P" instructions handle the
data transfer between the CPU and CM.
Procedure for setting up Freeport or 3964 (R) communication
1. Configure an S7-1500 configuration with CPU and CM in the device view of the hardware
and network editor of STEP 7.
2. Select the interface of the CM in the device view of STEP 7.
3. Assign the parameters of the interface (for example connection communication,
configuration of message sending) in the Inspector window of STEP 7 under "Properties" >
"General".
4. Select the "Send_P2P" or "Receive_P2P" instruction in the "Instructions" task card under
"Communication" > "Communications processor" and drag-and-drop the instruction into the
user program (for example into a FB).
5. Assign the parameters for the instructions according to your configuration.
6. Download the hardware configuration and user program to the CPU.
Otherwise: Dynamic parameter assignment of the communications module
In certain types of application it is an advantage to set up communication dynamically; in
other words, program-controlled by a specific application.
Typical applications for this, could be, for example manufacturers of serial machines. To make
the user interfaces as convenient as possible for their customers, these manufacturers adapt
the communications services to the particular operator entries.