MKS Baratron 740C, Руководство пользователя, Страница: 54 / 84

How To Check the Transducer Zero Chapter Two: Installation
44
Compound Gage Units
To properly zero a compound gage unit:
1. Install the transducer in a system with a power supply/readout.
2. Open the process port to local atmospheric pressure.
Note
The “reference” of the transducer is always open to the local atmospheric
conditions. The zero is set only when the Px (process port) is also open to
local atmospheric pressure.
3. Adjust the
ZERO
pot until the readout displays the voltage, or current, listed in Table 19.
Note
Compound Calibrations are gage instruments that provide an output above
and below ambient pressure. The zeroing process sets the output to the
value listed in Table 19 when the input pressure equals the local
atmospheric pressure. This is the output value of the unit
whenever the
input pressure equals the local atmospheric pressure, even if the local
atmospheric pressure has changed since the zero was set.
Output of a Compound Gage Unit at 0 psig
Range
inHg - 0 - psig
Output: 0 to 5 VDC Output: 0 to 10 VDC Output: 4 to 20 mA
30 - 0 - 30 1.6469 V 3.2938 V 9.270 mA
30 - 0 - 100 0.6421 V 1.2842 V 6.055 mA
30 - 0 - 250 0.2783 V 0.5566 V 4.891 mA
30 - 0 - 500 0.1431 V 0.2863 V 4.458 mA
30 - 0 - 1000 0.0726 V 0.1452 V 4.232 mA
30 - 0 - 2000 0.0366 V 0.0731 V 4.117 mA
30 - 0 - 3000 0.0244 V 0.0489 V 4.078 mA
Table 19: Output of a Compound Gage Unit at 0 psig
Span Adjustment
The span setting may require adjustment periodically. Only adjust the
SPAN
pot in conjunction
with a calibration transfer standard. Do not adjust the span setting if a calibration transfer
standard is not available. Instead, send the unit back to an MKS Service Center for calibration.