7
4.0 Operation
For most accurate pressure measurement, allow the Model 730 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 730 is linear with pressure; e.g., for a 10 VDC FS Model 730, 10
VDC equals 100% FS output; 1 VDC equals 10% FS output.
Table 1 indicates the lowest pressures recommended for reading and pressure control for
each range of the Model 730. The lowest suggested pressure for reading is limited by the
resolution and the accuracy of the Model 730. This is directly related to the electrical noise on
the signal output and can be significantly 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 minimal signal output of 50 mV.
NOTE:
if the unit has been exposed to sudden environmental changes, allow at least 2 hours
before making any adjustments.
Table 1: Recommended Lowest Pressures
Available for reading and pressure control
Full scale range
Lowest recommended
pressure reading
Recommended lowest
pressure for control
10 Torr
0.005 Torr
0.05 Torr
20 Torr
0.010 Torr
0.10 Torr
100 Torr
0.050 Torr
0.50 Torr
200 Torr
0.100 Torr
1.00 Torr
1000 Torr
0.500 Torr
5.00 Torr
10 mbar
0.005 mbar
0.05 mbar
20 mbar
0.010 mbar
0.10 mbar
100 mbar
0.050 mbar
0.50 mbar
1000 mbar
0.500 mbar
5.00 mbar
1 kPa
0.0005 kPa
0.005 kPa
2 kPa
0.0010 kPa
0.010 kPa
10 kPa
0.0050 kPa
0.050 kPa
100 kPa
0.0500 kPa
0.50 kPa
