Siemens Simatic S7-400 - Page 80

Interfaces, Networks and Data Communication for the S7-400
5-16
Automation System S7-400 Configuration and Use
A5E0044271 1-02
SFC Description
FB 3 READ This FB can be used to read a variable from a communication partner
without having to place a corresponding FB in the communication
partner.
FB 6 WRITE This FB can be used to write a variable to a communication partner
without having to place a corresponding FB in the communication
partner.
FB 4 REPORT Sends a structured variable to the communication partner
without acknowledgment.
FB 2 IDENTIFY Reads the identification of a non-Siemens system.
FB 5 STATUS Reads the status of a remote device on request.
SFBs for Point-to-Point Connections
Using the point-to-point connection via CP 441, you can link to all communication
partners that can handle the 3964(R), RK 512 or ASCII procedures. Non-Siemens
protocols are implemented with loadable drivers.
The communication SFBs require a point-to-point connection configured with
STEP 7. This connection runs from the CPU to the CP.
The communication SFBs that you can use are listed in the following table:
SFC Description
SFB 12
SFB 13
BSEND
BRCV
Transfer of a data block to the c ommunication partner. The
point-to-point CP acknowledges receipt of the data.
SFB 14 GET Reads data from a communication partner.
SFB 15 PUT Writes data to a communication partner.
SFB 16 PRINT Sends a message containing up to four variables to a printer.
SFB 22 STATUS Provides the status of the CPs and the RS 232 interface.
Function blocks for specific CPs are also supplied with the respective CPs.