Discrepancy Time Ix And Ix+1 Parameter; Table 31: Antivalent Pre-Evaluation - WAGO 750 Manual

WAGO I/O System 750
753-661/000-004 4FDI 24V PROFIsafe

Table 31: Antivalent Pre-Evaluation

Ix+1
0
0
1
1
After the amount of time specified in the Discrepancy Time setting has elapsed,
an invalid signal state causes a discrepancy error to be detected, which in turn
causes the channel pair in question to be passivated and the "Discrepancy Time
Exceeded" diagnostic message to be output; see section "Commissioning" > ... >

"Discrepancy Time Ix and Ix+1 Parameter."

If you have set the value of the Operating Mode parameter to "Rotary Table,"
you must set the Pre-Evaluation parameter to "Single-Channel."
Input signal changes caused by interference
Input signal changes caused by interference can cause the F I/O module to
transmit the value "0" to the safe PLC in the process image for the channel pair in
question, detect a discrepancy error after the discrepancy time has elapsed and
output the diagnostic message "Discrepancy time exceeded." Possible causes
may include:
• Cross circuit, short circuit and cable break (user error, wiring error)
• Stuck normally open contacts of a safe sensor
• Insufficient filtering of the test signals of a safe sensor
7.3.5.5 Discrepancy Time Ix and Ix+1 Parameter
The Discrepancy Time parameter is used for dual-channel pre-evaluation of two
digital inputs Ix and Ix+1. The discrepancy time is then only used by the F I/O
module when the Operating Mode parameter is set to "Standard" and the Pre-
Evaluation parameter is set to a value of "Equivalent" or "Antivalent."
The discrepancy analysis is only performed if both channels of a channel pair
have no channel error.
The signal states of the channel pair in question are evaluated according to a
parameterizable valence rule. The valence rule (equivalence, antivalence)
depends on the value of the Pre-Evaluation parameter (see section
"Commissioning" > ... > "Pre-Evaluation Parameter").
The F I/O module checks whether the valence rule violation has ceased after the
amount of time corresponding to the Discrepancy Time setting has elapsed. If it
has not, a discrepancy error is present. The channel pair is passivated, and the
diagnostic message "Discrepancy time exceeded" is output to the safe PLC.
Inputs
Ix
0
1
0
1
Version 1.0.0, valid from HW/SW Version 01/01
Commissioning
Process Image
Ix+1 Ix
0 0
1 1
0 0
0 0
67
Signal Status
Invalid
1-signal
0-signal
Invalid
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