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Scan Mode
When setup for scan mode, individual channels are displayed for a programmed
period of time. At the end of that time period the, display automatically switches
to the next channel. For ease of reading, the display first shows the channel
number (Format:
'CHANEL 1'
) and then the process variable along with the
programmed three digit engineering units e.g. 23.45 PSI.
Display time for each channel is programmable from 1-999 seconds (16.65 min.).
This is useful for adjusting display time to a rate which is consistent with the type
of process being monitored. Scan time for each channel is independent of display
time. This permits programming long display times without losing track of the
process on other channels.
The display can also be put in a hold mode by pushing the
SCN/HLD
key. When this key is pushed, the display will
briefly show
'HOLd'
after which the display will stop on the channel it was
indicating. Putting the unit in HOLD mode inhibits automatic display scanning
and shows only one particular channel. While the display is held on one channel,
internally all the enabled channels are continuously scanned for rate, difference,
limits and other parameters. Also, during HOLD mode the unit will periodically
flash the display
'Cx HOLd'
( x=channel # on hold) to indicate the status of the
display mode. If an attempt is made to hold on a channel that has been turned off
then the unit will indicate so by displaying in the format
'CHx OFF'
(
x=channel # off).
To select another channel for display during hold mode, push the
CH. SEL
key. Each push will increment the channel number. The display will first show
the channel number (e.g.
'CHANEL 2'
for channel # 2) followed by the process
variable in the form
'0.123 PSI'
. When channel selection is initiated using the
CH. SEL
key, the unit starts with
channel #1 and steps thru to channel #7 with each push of the key.
To take the unit out of HOLD mode and back into SCAN mode, push the
SCN/HLD
key. The display will briefly show
'SCAN'
and then start scanning the channels.
High/Low Channel Mode
DPS3300 Series compares all the channels against each other and constantly tracks
the channel with the highest and lowest process value. On push of a key, the
channel number and the value of process variable can be displayed. Also, during
SYS Setup, the unit can be programmed so that instead of scanning all the channels
it will only display the channel with highest or lowest process variable. As the
process changes, the display automatically switches over to the channel with the
highest (or lowest, if so programmed) reading. This is a very useful function for
applications involving multi-point monitoring of temperature in a single process.
For example, this feature can be used to find hot spots in a kiln. During high or low
channel scan mode the display will periodically flash
'HI CHAN'
or
'LO CHAN'
(depending upon the selected mode) to
indicate the status of the display mode.
To display high and low channel from any other display mode simply push the
HI/LO
key. Pushing this key once will
first display
'HI CHAN'
and then the channel number and the process value will be displayed in the format
'C2 1234'
.
The second push on the
HI/LO
key will first show
'LO CHAN'
in the display window, and then the channel with the
lowest process value will be displayed.
NOTE: (i) The second push, to display low channel, must be initiated before the display reverts back to the normal
display mode.
(ii) If a channel is selected using the
CH. SEL
key prior to the push on the
HI/LO
key, then instead of
displaying high and low channels, the unit will display high and low peaks of the active channel.
Therefore, if it is desired to display high and low channels and not the peaks, do not select a channel
before pushing the
HI/LO
key.
