Setra System Model Datum 2000 - Manual (Page 7)

7
OPERATING NOTES
OvEr AND UndEr MESSAGES
In addition to displaying the numeric pressure reading, the DATUM 2000™
may also display "UndEr" and OvEr". If the pressure reading exceeds
+31999 (disregard decimal point), the display will not show the input pres-
sure, instead it will display "OvEr". If the pressure reading is less than -9999
(disregard decimal point), the display will not show the input pressure,
instead it will display "UndEr".
SAMPLING RATE
The DATUM 2000™ will read the channel, 2 to 3 times a second. The speed
of the update is determined by the voltage of the channel being read. If the
meter has two channels calibrated, it will display each channel for 8 readings,
and then switch to the other channel. The exact time the meter will display a
channel is dependent on the voltage of that channel. Each channel will be
displayed for approximately 3 to 4 seconds.
LOCKING ONTO A CHANNEL
Press the HOLD/mode key to force the DATUM 2000™ to continuously
display the present channel. Upon power-up, the Datum 2000™ will display
both channels.
DISPLAYING BOTH CHANNELS
Press the SCAN/adj key to force the DATUM 2000™ to resume displaying
both channels.
MANOMETER ANALOG OUTPUT
The output of the Setra transducer installed in the DATUM 2000™ Manom-
eter is available at the rear terminal strip on pins 6 and 7 and marked Chan-
nel 1 +IN, Channel 1 -IN
RAPIDLY CHANGING INPUT SIGNAL
For a signal whose magnitude is increasing very rapidly, the DATUM 2000™
can select the wrong integration time. This can cause a single reading
overflow of the A/D converter. This overflow can cause the sign of the
reading to be incorrectly set. Such an occurrence can cause an improper
setting of the alarms. This condition will self-correct once the input signal
has stabilized. This occurrence will rarely, if ever, be seen.
TEST MODE
There is a test mode in which the DATUM 2000™ will display the output of
the A/D converter reading of Channel 1 without performing the units conver-
sion. This mode is accessible only by holding both the SCAN/adj and
HOLD/mode keys down when the power is applied to the DATUM 2000™.
If you accidentally enter this mode, you can exit by pressing either key.