Siemens SIMATIC S7 - F I;O Db; Using Substitute Values

1.2.3 F I/O DB
Default Settings for QBAD and PASS_OUT
Contrary to the description in Section 5.3.2 of the manual, the default setting for the
tags QBAD and PASS_OUT of the F-I/O DB is "1".
The default setting of "1" has no effect on safety programs that were created with
S7 Distributed Safety V 5.1.
1.2.4 Using Substitute Values
SM 336; AI 6 x 13-Bit: Substitute Value Output
The F-system identifies an overflow or underflow of a channel of the SM 336; AI 6 x
13-bit as an F-I/O fault or channel fault. The fail-safe value 0 is provided in place of
7FFF
H
(for overflow) or 8000
H
(for underflow) in the PII for the safety program.
Use of Individual Substitute Values
If in the case of an F-I/O with inputs, you want to process other substitute values
besides "0" in the safety program when substitute values are output, you can
specify individual substitute values when QBAD = 1 (see manual, Section 5.3.2).
Product Information for the S7 Distributed Safety, Configuring and Programming Manual
A5E00169432-02
31