Discrepancy Time Ix & Ix+1 Parameter - WAGO -I/O-SYSTEM 750 Manual

98 Commissioning
8.3.4.4 Discrepancy Time Ix & Ix+1 Parameter
Do not use discrepancy time monitoring as part of the safety function!
You can only use discrepancy monitoring for safety applications where
monitoring of both contacts does not represent its own safety function such as
emergency stop and the opposite, two-hand control!
The discrepancy time parameter is used for two-channel analysis of two digital
inputs Ix & Ix+1. The discrepancy time is then only used by the F I/O module
when the operating mode is set to "Standard" and the value of the two-channel
analysis parameter is set to "yes".
If you have set the Two-channel analysis parameter is set to "yes", the signal
states of the affected input pair are evaluated based on an adjustable valence
rule. The valence rule (antivalence, equivalence) depends on the value of the
Valence analysis parameter (see section "Commissioning" > ... > "Parameter
Valence Evaluation Ix & Ix+1").
The F I/O module checks whether the difference from the valence rule has
disappeared after the configured discrepancy time has elapsed. If not, a
discrepancy error is present. The F I/O module is passivated and the
"Discrepancy time exceeded" diagnostic message is output to the safe PLC.
Use the value of the parameter to specify the maximum permissible time for a
deviation (illegal signal state) of both input signal states of the valence rule.
The F I/O module begins discrepancy monitoring as soon as a deviation of the
input signal states from the valence rule is detected.
Discrepancy time monitoring is terminated when a valid signal status is achieved
(0-signal or 1-signal, see section "Commissioning" > ... > "Parameter Valence
Evaluation Ix & Ix+1"), depending on the signal status that was present at the
digital inputs prior to the beginning of discrepancy monitoring.
You can set the discrepancy time in a value range from 10 ms to 65535 ms for
each input pair separately.
Discrepancy Time Monitoring and Discrepancy Time
The discrepancy time monitoring feature checks whether there are impermissible
delays between the signals at the two input channels. This can be used, for
example, to detect mechanical or electro-mechanical deviations from the nominal
state of simultaneity.
Discrepancy time monitoring of the two-channel analysis is used to determine
sensor errors based on the chronological progression of the signal states.
Discrepancy time monitoring is activated if the signal states deviate from the
valence rule when:
Manual
Version 1.4.2, valid from HW/SW Version 01/02
750-667/000-003 4FDI/4FDO 24V/2A PROFIsafe V2 iPar
WAGO-I/O-SYSTEM 750