Omron NE1A Series - Page 113

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Function Block Editing Section 6-3
Discrepancy Time
If the function block input type is set to Dual Channel Equivalent or Dual
Channel Complementary, the discrepancy time (i.e., the time between
changes in the inputs) can be evaluated.
The time between when one of the dual-channel inputs changes until the
other one changes is monitored. If the second dual-channel input does not
change before the discrepancy time expires, an error will occur and the Out-
put Enable output from the function block will not turn ON.
The dual channel modes can be used to detect faults in safety devices and
safety device wiring monitored by the function block.
The time between changes in the inputs will not be monitored if the discrep-
ancy time is set to 0.
The discrepancy time is evaluated both when the input signals go from active
to inactive and from inactive to active.
■ Normal Operation
Example for Dual Channel Equivalent Setting
Dual channel mode Input signals Input signal status
Input
1
Input
2
Dual Channel Equivalent
• Input 1: NC
• Input 2: NC
0 0 Inactive
0 1 Discrepant
1 0 Discrepant
11 Active
Dual Channel Complementary
• Input 1: NC
• Input 2: NO
0 0 Discrepant
0 1 Inactive
10 Active
1 1 Discrepant
Discrepancy time
Input 1
Input 2
Discrepancy time
Output
Enable
Discrepancy Normal
Error