Omron DRT2 Series Operation Manual page 173

Analog Input Terminals
Top/Valley Hold
Setting Using the
DeviceNet
Configurator
1,2,3...
156
5. Click the Download Button and then click the Reset Button to reset the
Unit.
6. Click the OK Button and exit the window.
Top/valley hold is used to hold the top and valley values of the analog input
value.
Analog values that fluctuate more than twice the hysteresis value are moni-
tored, and the top or valley values are held. The top or valley value is allo-
cated 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 analog data. (Refer to details on the comparator function.)
Example of Valley Hold
Hold value
Hold Flag
Hold function starts
Top/Valley Detection
Timing Flag
Note 1. A delay in network transmission time will occur from the time the Hold Flag
turns ON (or OFF) in the Master'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 analog data transmitted to the Master 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, con-
figure a ladder program which considers the transmission delay time when
the Hold Flag is turned ON, then enables the top/valley 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 Configurator to set the one-shot
time (the setting range is 1 to 65535 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.
1. Double-click the icon of the Analog Slave to be set in the Main Window and
open the Edit Device Parameters Window. (From the Maintenance Mode
Window, click the right mouse button over the Slave icon and select Pa-
rameters and Edit.)
Analog input value
One-shot time
Section 7-3
Valley hold value
Last value is held.
Hold function stops