Omron NE1A-SCPU01 - 2006 Operation Manual page 129

Common Functions
Note
94
(1) The Total ON Time Monitor function (Time) and Contact Operation
Counter function (Count) cannot be used simultaneously on one bit. Se-
lect one of these functions with the Maintenance Counter Mode Choice
setting.
(2) When the Maintenance Counter Mode Choice setting is changed, the col-
lected data (operations count or total ON time) will be cleared.
(3) These functions do not operate when the I/O power supply is OFF.
(4) The Total ON Time Monitor function checks whether the connected de-
vice is ON at about 1-s intervals. This function may not count the total ON
time precisely if the device is ON for intervals of less than 1 second.
Calculating the Total ON Time with 0.5-s ON Pulses
In figure A, the bit is actually ON for 0.5 s
once when the status is checked, so the total ON time is measured as 1 s.
Measured about 1 time/second
0.5 s
Figure A
In figure B, the bit is actually ON for 0.5 s
when the status is checked, so the total ON time is measured as 2 s.
Measured about 1 time/second
0.5 s
Figure B
Calculating the Total ON Time with 1.5-s ON Pulses
In figure C, the bit is actually ON for 1.5 s
when the status is checked, so the total ON time is measured as 4 s.
Measured about 1 time/second
1.5 s
Figure C
Section 5-1
3 = 1.5 s, but the bit is ON just
3 = 1.5 s, but the bit is ON twice
2 = 3 s, but the bit is ON four times