Omron CJ-Series Operation Manual page 104

Built-in Inputs
Counting Modes
Linear Mode
Ring Mode
• Only up-differentiated pulses (rising edges) can be counted.
Input pulses can be counted in the range between the lower limit and upper
limit values. If the pulse count goes beyond the lower/upper limit, an under-
flow/overflow will occur and counting will stop.
Lower and Upper Limits of the Range
The following diagrams show the lower limit and upper limit values for incre-
ment mode and up/down mode.
Increment Mode
0
(000000 Hex)
Up/Down Mode
−2147483648
(80000000 Hex)
PV underflow
Input pulses are counted in a loop within the set range. The loop operates as
follows:
• If the count is incremented from the max. ring count, the count will be
reset to 0 automatically and incrementing will continue.
• If the count is decremented from 0, the count will be set to the max. ring
count automatically and decrementing will continue.
Consequently, underflows and overflows cannot occur when ring mode is
used.
Count value
−1
32
2
Max. ring
count
0
Max. Ring Count
Use the PLC Setup to set the max. ring count, which is the max. value of the
input pulse counting range. The max. ring count can be set to any value
between 00000001 and FFFFFFFF hex.
Restrictions
• There are no negative values in ring mode.
• If the max. ring count is set to 0 in the PLC Setup, the counter will operate
with a max. ring count of FFFFFFFF hex.
0
(00000000 Hex)
Section 5-1
4294967295
(FFFFFFFF Hex)
PV overflow
+2147483647
(7FFFFFFF Hex)
PV overflow
85