Setra System Model Datum 2000 - Manual (Page 16)

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PRESSURE (@ 0) = 200 x 0 + 0 = 0
PRESSURE (@ REF) = 200 x 2.4995 + 0 = 499.9
2nd example:
A 20 psi transducer has an offset of .1 volts and will have an output of 5.1
volts for a 20 PSI pressure. The DATUM 2000™ has a 2.4993 reference
voltage.
20 – 0
SLOPE = ———— = 4
5.1 – .1
OFFSET = 0 – 4 x .1 = –.4
PRESSURE (@0) = 4 x 0 – .4 = –.4
PRESSURE (@ REF) = 4 x 2.4993 – .4 = 9.597
3rd example:
A bidirectional transducer has +/- 2.5 volt output for +/- 14.70 reading. The
DATUM 2000™ has a reference voltage of 2.5082 volts.
14.70 – (–14.70)
SLOPE = —————————— = 5.88
2.5 – (–2.5)
OFFSET = 14.70 – 5.88 x 2.5 = 0
PRESSURE (@ 0) = 0 x 5.88 – 0 = 0
PRESSURE (@ REF) = 2.5082 x 5.88 – 0 = 14.75
CALIBRATING THE DATUM 2000™ FOR A TRANSMITTER USING THE
INTERNAL REFERENCE VOLTAGE
The DATUM 2000™ has a very stable internal reference voltage which can
be used for calibration with transmitters. Before proceeding you must locate
the label on the bottom of the DATUM 2000™ which indicates the reference
voltage and the value of the transmitter input impedance for the channel you
wish to calibrate.