Parameter Valence Evaluation Ix & Ix+1; Table 41: Antivalent Evaluation - WAGO -I/O-SYSTEM 750 Manual

100 Commissioning
8.3.4.5 Parameter Valence Evaluation Ix & Ix+1
The Valence evaluation parameter is used for the dual channel evaluation of
two digital inputs Ix & Ix+1. The valence evaluation is then only used by the F I/O
module if you have set the value of the Operating mode parameter to "Standard"
and the value of the Dual channel evaluation parameter to "yes".
The Valence evaluation parameter is used to set the valence rule of the dual
channel evaluation to be used for an input pair. You can set the parameter to
"Antivalent" or "Equivalent". The valence evaluation can be set separately for
each input pair.
Changing input signals caused by interference
Changing input signals 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 input pair
affected, a discrepancy error to be detected after the discrepancy time has
elapsed and the "Discrepancy time exceeded" diagnostic message to be output.
Possible causes may be:
• Cross circuit, short circuit and broken cable (user error,
wiring error)
• Sticky normally open contacts of a reliable sensor
• Inadequate filtering of the test signals of a reliable sensor
If you have set the Valence evaluation parameter to "Antivalent", then the F I/O
module behaves as follows:
The F I/O module compares the signal states of the digital inputs affected to the
opposing values. The following table shows the possible signal states for the
antivalent evaluation:

Table 41: Antivalent Evaluation

I2
I4
0
0
1
1
After the set discrepancy time has elapsed, an illegal signal state leads to the
detection of a discrepancy error by which the F I/O module is passivated and the
"Discrepancy time exceeded" diagnostic message is output.
If you have set the Valence evaluation parameter to "Equivalent", then the F I/O
module behaves as follows:
Manual
Version 1.4.2, valid from HW/SW Version 01/02
750-667/000-003 4FDI/4FDO 24V/2A PROFIsafe V2 iPar
Inputs
I1
I3
0
1
0
1
WAGO-I/O-SYSTEM 750
Process Image
Bit 1 Bit 0
Bit 3 Bit 2
0 0
0 1
0 0
0 0
Signal State
Illegal
1 Signal
0 Signal
Illegal