MKS PR 4000 F, Instruction Manual

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Chapter 4: Operation PR4000F
24
Gain and Offset
(extra windows for channel 1 and channel 2)
GAIN is a factor which adapts the range and the measurement signal for correct readout. A typical
application is to use the gain factor as the gas correction factor with thermal mass flow meters or
mass flow controllers.
Available range setting: 0.001 – 2.000.
Example for a MFC at channel 1, calibrated for 200 sccm full scale of nitrogen. The process gas
used is carbon dioxide CO
2
. The gas correction table in the user manual of the mass flow controller
indicates a gas correction factor of 0.70 .
Range setting: RNG1 200.00 sccm
Gas correction factor setting: GAIN 00.7000
This finally results in a range of 0 – 140 sccm CO
2
, which is displayed correctly by the PR4000F.
OFFS is the zero offset value of the respective input signal. Typically the zero offset is corrected by
the auto zero cycle (refer to section Control ) and the resulting value is shown here. It also possible
to enter the respective value here which may be necessary in exceptional cases.
Range Turndown Offset
The PR4000F allows the user to switch a Baratron 120 series in the range turndown mode
automatically. This is described in detail in the section
Control . The auto zero mode determines the
zero offset value of both ranges to achieve highest accuracy.
It is of course also possible to enter the offset values for both ranges manually as described in the
menu before.
GAIN1 01.0000
OFFS1 - 00043 mV
RTDOFFS1 -005 mV
RTDOFFS2 000 mV