401-405 SERIES
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3.4.2.3.6. Reverse Flow
If the flow through the flow
meter reverses and flow
begins to enter the exit of the
flow meter and leave through
the entrance of the flow meter
the flow meter will measure
this flow and report it digitally
with reduced accuracy. The
analog output will also
indicate this by either
generating a negative output
voltage or decreases the
current output below 4 mA,
depending on whether a
voltage or current output has
been selected.
3.7. High Pressure
Operation
When operating at high
pressure, the meter’s
performance can be affected
in two distinct and separate
ways—a zero shift and a span
(calibration) shift.
Figure 3-1 The pressure effect on flow calibration (for nitrogen)
Pressure Effect
-1
0
1
2
3
4
5
6
7
8
0 200 400 600 800 1000
Line Pressure (psig)
Span Shift (% Reading)
Flow meter Output
0%
50%
100%
150%
200%
250%
0% 100% 200% 300% 400% 500% 600%
Flow (% Full Scale)
Indicated Flow (% Full Scale
Analog Output
Digital Output
