19
3.5.2 Diagnostic displays
The diagnostic displays are used to evaluate
abnormalities in the process stream.
• The
standard electrical deviation
(StdE) is
related to the level of electrical fluctuation in the
input signal reference. The value is displayed in
terms of volts, ie "0.02" represents 20 millivolts.
Nominal values range from 50 mV at low
velocities to 80 mV at maximum velocity. Higher
values indicate excessive fluid noise levels, or
inadequate earth ground. Use the Sensitivity
adjustment (sec 3.4.1) to compensate and check
the grounding requirements (sec. 2.6).
• The
standard flow deviation
(StdF) is an
overall indication of the stability of the flow signal.
It incorporates the StdE, as well as mechanical
factors such as unstable flow profiles, misaligned
sensors, and coated electrodes. StdF is displayed
as a percentage of flow rate, typically from 5 to
8%. StdF levels in excess of 10% indicate
inadequate installation or application standards.
If StdE value is high, the StdF will always be high.
If StdE is low but StdF is high, look for causes
related to sensor location, such as insufficient
upstream straight runs and sensor alignment. If the
StdF cannot be corrected by modifying the
installation, the Response function (sec 3.4.2) will
help to smooth the output signals.
Code entry is not necessary to change the display
setting.
Use the up arrow to move
quickly to the display options.
RatE is the factory default
setting.
Example illustrates changing
display setting to StdE.
RUN
EDIT
ENTER
1.
2.
3.
Step:
Press:
To display:
Selecting the StdE or StdF
diagnostic displays will not
affect or interrupt the outputs.
Summary of Contents for +GF+ SIGNET 2550
Page 1: ...GEORGE FISCHER GF GF SIGNET 2550 Insertion Magmeter Instruction Manual...
Page 34: ...NOTES...
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