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F-Libraries
6.1.2.12
FB 211 "F_2H_EN": Two-Hand Monitoring with Enable
Connections
Inputs
Parameter Data Type Description
Default
IN1
BOOL
Momentary-contact switch 1
FALSE
IN2
BOOL
Momentary-contact switch 2
FALSE
ENABLE
BOOL
Enable input
FALSE
Discrepancy time (0 to 500 ms)
T# 0 ms
DISCTIME TIME
Outputs
Q
BOOL
1= Enable
FALSE
DIAG
BYTE
Service information
B#16#0
Principle of Operation
This F-application block implements two-hand monitoring. If momentary-contact
switches IN1 and IN2 are activated within the permissible discrepancy time
DISCTIME ≤ 500 ms (IN1/IN2 = 1) (synchronous activation), output signal Q is set
to 1 when existing enable ENABLE = 1. If the time difference between activation of
momentary-contact switch IN1 and momentary-contact switch IN2 is greater than
DISCTIME, then the momentary-contact switches must be released and
reactivated.
Q is reset to 0 as soon as one of the momentary-contact switches is released
(IN1/IN 2 = 0) or ENABLE = 0. Enable signal Q can be reset to 1 only if the other
momentary-contact switch has been released, and if both switches are then
reactivated within the discrepancy time when existing enable ENABLE = 1.
The F-application block supports requirements in accordance with EN 574.
Note: Only one signal per momentary-contact switch can be evaluated at the
F-application block. With suitable configuration (type of sensor interconnection:
2-channel, nonequivalent), the discrepancy monitoring of the NC and NO contacts
of the IN1 and IN2 momentary-contact switches is performed directly by the F-I/O
with inputs. The NO contact must be wired in such a way that it supplies the useful
signal (see manual for the F-I/O you are using). In order to keep the discrepancy
time from influencing the response time, you must assign "Provide a value of 0" for
the discrepancy behavior during configuration.
If a discrepancy is detected, a fail-safe value of 0 is entered in the process input
image (PII) for the momentary-contact switch and QBAD is set to 1 in the relevant
F-I/O DB.
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S7 Distributed Safety, Configuring and Programming
A5E00109537-02