Omron SYSMAC CJ Series User Manual page 136

7 High-speed Counters
Precautions for Correct Use Precautions for Correct Use
• When the count direction (incrementing/decrementing) changes at a PV that matches a target
value, the next target value will not be matched in that direction.
Set the target values so that they do not occur at the peak or trough of count value changes.
Bad
Target value 1
Target value 2
• The comparison conditions (target value and count directions) cannot be set more than once
in the same table. An instruction error will occur if the same comparison conditions appear
twice.
• An instruction error will occur if "when decrementing" is set as the comparison condition when
the high-speed counter is set to Increment Pulse Input Mode.
• The maximum response frequencies of the high-speed counters are given in the following
table.
Pulse I/O Module
No.
0 (on the right)
1 (on the left)
7-26
OK
Match/Target value + 1
Target value 1
Target value 2
Do not match.
Item
Increment pulse
Up and down pulses
High-speed
counter 0 or 1
Pulse + Direction Mode
Differential phase (×4)
Increment pulse
Up and down pulses
High-speed
counter 2 or 3
Pulse + direction
Differential phase (×4)
Match
Target value + 2 or higher
Match
Maximum response
frequency
100 kHz
50 kHz
100 kHz
50 kHz
CJ2M CPU Unit Pulse I/O Module User's Manual