Fb 190 "F_1Oo2Di": 1Oo2 Evaluation With Discrepancy Analysis - Siemens SIMATIC S7 Configuration And Programming Manual

1.2.14

FB 190 "F_1oo2DI": 1oo2 Evaluation with Discrepancy Analysis

Connectors
Parameter Data
Inputs
IN1
IN2
DISCTIME TIME
ACK_NEC BOOL
ACK
Outputs Q
ACK_REQ BOOL
DISC_FLT BOOL
DIAG
Mode of Operation
This F application block implements a 1oo2 evaluation of two single channel
sensors combined with a discrepancy analysis.
The output Q is set to 1, when the signal states of the two inputs IN1 and IN2 equal
1 and no discrepancy error DISC_FLT is stored. if the signal state of one or both
inputs is 0, output Q is set to 0.
As soon as the signal states of the two inputs IN1 and IN2 are different, the
discrepancy time DISCTIME is started. If the signal states of the two inputs are still
different when the discrepancy time elapses, a discrepancy error is detected and
DISC_FLT is set to 1 (restart disabled).
If no discrepancy is detected between inputs IN1 and IN2, the discrepancy error is
acknowledged depending on the parameter assignment of ACK_NEC:
•
If ACK_NEC = 0 the acknowledgment is automatic.
•
If ACK_NEC = 1 you can only acknowledge the discrepancy error with a rising
edge at input ACK.
The ACK_REQ = 1 output signals that a user acknowledgment is necessary at
input ACK to acknowledge the discrepancy error (cancel the restart disable). The
F application block sets ACK_REQ = 1 as soon as discrepancy is no longer
detected. After acknowledgment or when there is once again a discrepancy
between the inputs IN1 and IN2 before the acknowledgment, the F application
block resets ACK_REQ to 0.
The output Q can never be set to 1 if the discrepancy time is set to values < 0 or >
60 s. In this case, the output DISC_FLT is also set to 1 (restart disabled). The call
interval of the safety program (for example OB35) must be less than the set
discrepancy time.
Product Information for the S7 Distributed Safety, Configuring and Programming Manual
A5E00169432-02
Description
Type
BOOL Sensor 1
BOOL Sensor 2
Discrepancy time (0 ... 60 s)
1 = acknowledgment necessary for discrepancy
error
BOOL Acknowledgment of discrepancy error
BOOL Output
1 = acknowledgment necessary
1 = discrepancy error
Byte Service information
Default
0
0
T# 0 ms
1
0
0
0
0
0
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