Omron CJ1M-CPU21, Operation Manual

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Features Section 1-1
1-1 Features
1-1-1 Built-in I/O Functions
The CJ1M CPU Units are high-speed, advanced, micro-sized PLCs equipped
with built-in I/O. The built-in I/O have the following features.
General-purpose I/O
Immediate Refreshing The CPU Unit's built-in inputs and outputs can be used as general-purpose
inputs and outputs. In particular, immediate I/O refreshing can be performed
on the I/O in the middle of a PLC cycle when a relevant instruction is exe-
cuted.
Stabilizing Input Filter
Function The input time constant for the CPU Unit's 10 built-in inputs can be set to 0 ms
(no filter), 0.5 ms, 1 ms, 2 ms, 4 ms, 8 ms, 16 ms, or 32 ms. Chattering and
the effects of external noise can be reduced by increasing the input time con-
stant.
Interrupt Inputs
High-speed Interrupt Input
Processing The CPU Unit's 10 built-in inputs can be used for high-speed processing as
regular interrupt inputs in direct mode or interrupt inputs in counter mode. An
interrupt task can be started at the interrupt input's rising or falling edge (up or
down differentiation.) In counter mode, the interrupt task can be started when
the input count reaches the set value (up-differentiated or down-differentiated
transitions.)
High-speed Counters
High-speed Counter
Function A rotary encoder can be connected to a built-in input to accept high-speed
counter inputs.
Trigger Interrupts at a
Target Value or in a
Specified Range Interrupts can be triggered when the high-speed counter’s PV matches a tar-
get value or is within a specified range.
Measure the Frequency of
High-speed Counter
Inputs The PRV(881) instruction can be used to measure the input pulse frequency
(one input only.)
Maintain or Refresh
(Selectable) High-speed
Counter PVs The High-speed Counter Gate Bit can be turned ON/OFF from the ladder pro-
gram to select whether the high-speed counter PVs will be maintained or
refreshed.
Pulse Outputs
Fixed duty ratio pulses can be output from the CPU Unit's built-in outputs to
perform positioning or speed control with a servo driver that accepts pulse
inputs.
CW/CCW Pulse Outputs or
Pulse + Direction Outputs The pulse output mode can be set to match the motor driver's pulse input
specifications.
Automatic Direction
Selection for Easy
Positioning with Absolute
Coordinates When operating in absolute coordinates (origin defined or PV changed with
the INI(880) instruction), the CW/CCW direction will be selected automatically
when the pulse output instruction is executed. (The CW/CCW direction is
selected by determining whether the number of pulses specified in the instruc-
tion is greater than or less than the pulse output PV.)