1 Overview
1-4
CJ2M CPU Unit Pulse I/O Module User’s Manual
1-2 Overview of the Functions of CJ2M
Pulse I/O
The following functions of the pulse I/O of the CJ2M can be used by installing a Pulse I/O Module.
Select which function to use for each input and output in the PLC Setup.
The inputs and outputs on the Pulse I/O Module can be used as normal inputs and normal outputs.
(Each Pulse I/O Module provides up to 10 inputs and 6 outputs.) The input time constant can be set to
0 ms (no filter), 0.5 ms, 1 ms, 2 ms, 4 ms, 8 ms, 16 ms, or 32 ms. The same setting is used for all 20
inputs. Chattering and the effects of external noise can be reduced by increasing the input time con-
stant.
By setting an input on the Pulse I/O Module to quick-response input operation, inputs with signal widths
as small as 30 µs can be read with certainty regardless of the cycle time. Up to four quick-response
inputs can be used for each Pulse I/O Module (eight for the entire CJ2M PLC).
An interrupt task can be started when an input on the Pulse I/O Module turns ON or OFF (Direct Mode).
Alternatively, the rising or falling edge of the inputs can be counted. When the count reaches a specified
value, an interrupt task can be started. This is called Counter Mode. Up to four interrupt inputs can be
used for each Pulse I/O Module (eight for the entire CJ2M PLC).
A rotary encoder can be connected to the Pulse I/O Module input to accept differential phase or single-
phase high-speed pulse counter inputs.
High-speed counter inputs (differential phase: 50 kHz, single-phase: 100 kHz) for up to 2 axes can be
used for each Pulse I/O Module (up to 4 axes for the entire CJ2M PLC).
z Use the Linear Mode or Ring Mode for the Counting Mode
The maximum value of the ring counter can be changed during operation using the MODE CON-
TROL (INI(880)) instruction.
z Start Interrupt Tasks Using Target Value Comparison or Range Comparison
for High-speed Processing
Interrupt tasks can be started when the PV reaches a target value for target value comparison, or
when it enters a specified range for range comparison.
z Frequency Measurement
The input pulse frequency can be measured by executing the HIGH-SPEED COUNTER PV READ
(PRV(881)) instruction. (Applicable only to high-speed counter 0.) It is possible to convert the fre-
quency to a rotational speed by executing the COUNTER FREQUENCY CONVERT (PRV2(883))
instruction.
Functions of Normal I/O
Quick-response Inputs
Interrupt Inputs
High-speed Counters
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