Seneca S6001-RTU, User Manual

Page: 191 / 210

USER MANUAL – Z-TWS4/Z-PASS2-S/S6001-RTU
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19.1.16 S7_DB_READ
This FB performs an S7 protocol Data Block read operation.
It connects to the specified S7 server IP address, rack and slot, performs the
operation and then disconnects.
The data read are written to the Straton shared-memory specified in the SHM_NAME
parameter.
INPUTS:
- SERVER_ADDR: the S7 server IP address
- SERVER_RACK: the S7 server rack number
- SERVER_SLOT: the S7 server slot number
- SHM_NAME: name of the Straton shared-memory which the data are written to
- SHM_SIZE: size of the Straton shared-memory which the data are written to
- DB_NUM: the number of the Data Block to be read
- OFFSET: start offset for the read operation in the Data Block
- LEN: number of bytes to be read
- TIMEOUT: timeout for the FB execution, in seconds
- @ENABLE: TRUE -> FB is executed
FALSE -> FB is skipped
the parameter is set to FALSE by the FB at the end of execution
OUTPUTS:
- RESULT: the FB result; possible values are:
0: FB still running
1: FB successfully executed
-1: FB execution failed
-2: FB execution timeout
- S7_CLI_RESULT: the S7 Client result; possible values are:
0: no failure
-1: invalid arguments failure
-2: initialization failure (e.g.: error opening the shared-memory)
-3: connection failure
-4: read operation failure