7
4.0 OPERATION
For most accurate pressure measurement, allow the Model 760 to warm up for at least 15
minutes. After installation, periodically check the zero output reading to verify correct output.
Adjust the zero potentiometer if incorrect (See Section 5 for zero adjustment instructions).
The signal output of the Model 760 is linear with pressure; e.g., for a 10 VDC FS Model 760, 10
VDC equals 100% FS output, 1 VDC equals 10% FS output.
Table 1 indicates the lowest pressures available for reading and pressure control for each
range of the Model 760. The lowest suggested pressure available for reading is limited by the
resolution and the accuracy of the Model 760. This is directly related to the electrical noise on
the signal output and can be signicantly effected by incorrect electrical ground connection,
or connection to an electronically noisy power supply or readout instrument. Improved results
may be obtained if the transducer is operated in an environment with stable temperature and
air flow. The lowest recommended pressure used for control applications, such as a closed
loop downstream pressure control system, is based on a signal output of 50 mV.
Table 1: Recommended lowest pressures
Available for reading & pressure control
Full scale range
Recommended lowest
pressure reading
Recommended lowest
pressure for control
10 Torr 0.005 Torr 0.05 Torr
20 Torr 0.010 Torr 0.10 Torr
50 Torr 0.025 Torr 0.25 Torr
100 Torr 0.050 Torr 0.50 Torr
200 Torr 0.100 Torr 1.00 Torr
500 Torr 0.250 Torr 2.50 Torr
1000 Torr 0.500 Torr 5.0 Torr
10 mbar / hPa 0.005 mbar / hPa 0.05 mbar / hPa
100 mbar / hPa 0.05 mbar / hPa 0.5 mbar / hPa
1000 mbar / hPa 0.5 mbar / hPa 5 mbar / hPa
1 psia 0.0005 psia 0.005 psia
2 psia 0.0010 psia 0.010 psia
5 psia 0.0025 psia 0.025 psia
10 psia 0.0050 psia 0.050 psia
20 psia 0.0100 psia 0.100 psia
