Siemens Simatic S7-400 - Page 74

Function Blocks
The table below contains the function blocks of the CP 440 and describes their purpose.
Table 6-1 Function Blocks of the CP 440
FB/FC Meaning Protocol
FB 9 "RECV_440" The RECV_440 function block allows you to receive data from a commu‐
nication partner and store it in a data block.
ASCII driver, 3964(R)
procedure
FB 10 "SEND_440" The SEND_440 function block allows you to send all or part of a data block
to a communication partner.
ASCII driver, 3964(R)
procedure
FB 11 "RES_RECV" The RES_RECV function block enables you to reset the receive bu󹪜er of the
CP 440.
ASCII driver, 3964(R)
procedure
Note
The maximum CP440 frame length was extended from 200 to 400 bytes.
To use this feature, you have to 󹪝rst install version V5.1.7 or higher from the PtP - Param. During
installation, the two function blocks
FB9 V1.1 (RECV_440)
and
FB10 V1.1 (SEND_440)
are available in the CP PtP SIMATIC Standard Library in the subfolder CP440/Blocks. Only when
using these blocks you can transfer more than 200 bytes (i.e. up to 400 bytes) with your CP440.
Application in Existing User Projects:
If you want to extend the existing CP440 applications for the operation of up to 400 bytes frame
length, you have to 󹪝rst delete the concerned CP440 in HW Con󹪝g and then recon󹪝gure it with
a PtP - Param V5.1.7 or higher. Furthermore, you have to replace the two function blocks FB9
and FB10 (see above) with each new version V1.1 in your user program.
Scope of Supply and Installation
The function blocks of the CP 440 are on CD along with the parameter assignment interface, the
programming examples and the manual.
The function blocks are installed together with the parameter assignment interface. After
installation, the function blocks are stored in the CP 440 library.
You can open the library in STEP 7 SIMATIC Manager by selecting File > Open > Library under
"CP PTP\CP 440\Blocks".
To work with the function blocks, you only need to copy the required function block to your
project.
See also
Parameters for the Communications Protocols (Page 56)
Communication via Function Blocks
6.1 Overview of the Function Blocks
Point-to-point connection CP 440 Installation and Parameter Assignment
74 Equipment Manual, 03/2022, A5E00057742-AE