Omron CRT1 - 10-2008, Operation Manual

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Temperature Input Unit Functions Section 11-5
11-5-4 Top/Valley Hold
The top/valley hold function is used to hold the top and valley values of the
temperature input value.
Temperature values that fluctuate more than twice the hysteresis value are
monitored, and the top or valley values are held. The top or valley value is
allocated along with the Top/Valley Detection Timing Flags, which can be
used to check the hold timing.
When the Hold Flag (output) allocated in the OUT Area turns ON, the hold
function starts, refreshing the top or valley value until the Hold Flag turns OFF.
(The last value is held when the Hold Flag turns OFF, but the next time the
Hold Flag turns ON, the hold value is initialized as soon as a top or valley
occurs.) The comparator can be used to compare the top or valley value allo-
cated as Temperature Data 1. (Refer to details on the comparator function.)
Example of Valley Hold
Note 1. A delay in network transmission time will occur from the time the Hold Flag
turns ON (or OFF) in the Master Unit's ladder program until notification of
the flag's status is actually sent to the Slave. Therefore, even when the
Hold Flag is ON, the first temperature data transmitted to the Master Unit
when the CPU Unit power is turned ON may be the data from when the
Hold Flag was OFF. To collect top/valley hold data using the Hold Flag at
the Master Unit, configure a ladder program which considers the transmis-
sion delay time when the Hold Flag is turned ON, then enables the top/val-
ley hold values after a fixed time interval.
2. The time that the Top/Valley Detection Timing Flags are ON can be adjust-
ed by setting the one-shot time. Use the CX-Integrator to set the one-shot
time (the setting range is 1 to 65,535 ms).
3. If the Hold Flag turns OFF during the time the Top/Valley Detection Timing
Flag is set to be ON, both flags will turn OFF simultaneously.
Setting Using CX-Integrator
1,2,3... 1. Turn ON the power supply to the Temperature Input Unit.
2. Double-click the icon of the Temperature Input Unit to be set in the Network
Configuration Window or right-click the icon and select
Parameter - Edit .
The Configuration Window will be displayed.
3. Click the tab for the input where top/valley hold is to be set, and select the
Top/Valley Check Box in the Function Choice Area.
Temperature
input value
Hold value
Top/Valley Detection
Timing Flag
Hold Flag
One-shot time
Hold function
starts.
Hold function
stops.
Valley hold
value
Last value
is held.