Omron CRT1 - 10-2009, Operation Manual

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502
Functions of Digital I/O Slave Units
Section 11-3
11-3-6 Operation Time Monitor
Description
This function can be used to measure the contact I/O timing (ON/OFF) in the
Slave Unit (measurement unit: ms) and store the measurement in the Slave
Unit memory. (This data can be read using the CX-Integrator or using explicit
messages.)
The operation time of various combinations of contacts can be monitored in
the Slave Unit (e.g., input-output, output-input, input-input, and output-output).
In addition, the trigger edge pattern can be set to ON
→
OFF, ON
→
ON,
OFF
→
OFF, or OFF
→
ON. Any input number and output number combination
can also be set. (The number of contact points that can be set depends on the
Unit.)
This function allows high-precision measurement of the operation time without
being affected by the communications cycle. A monitor value can be stored in
the Slave Unit memory so once the set monitor time has been exceeded, a
flag in a status area in the Slave Unit turns ON to notify the Master Unit. The
notification details can be read using the CX-Integrator or using explicit mes-
sages.
• The operation time is stored after the time lag from when the output turns
ON until when the input turns ON is measured. The operation time contin-
ues to be measured internally until the next output turns ON. The mea-
surement value is refreshed if the input turns ON again before the next
output turns ON. For cylinders and other applications with reciprocating
operation that receive inputs during the operating time, the measurement
taken during operation (outward motion) may be refreshed during the
release (return motion).
Alternatively, if the output turns ON twice before the input turns ON, the
time measured is from when the second output turns ON till when the input
turns ON.
Note (1) If the same contact is used for the start and end of measurement and the
same trigger edge pattern is used for both, the measured time will always
be 0 ms.
(2) If monitor settings are changed while this function is being used, the ac-
curacy of subsequent monitoring operations cannot be guaranteed. Cor-
ON
OFF
ON
OFF
t1
t2
t3
t1 t2 t3
Operation
Time
Monitor
(Previous value)
Output
Input
ON
OFF
ON
OFF
Output
Input
Measures this time period.