Honeywell Vertex M, Technical Handbook

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Vertex M
TM
24-Point Continuous Monitor
Appendix A - Line Integrity Test Option H-2
Honeywell Analytics now offers the optional capability
to check for leaks in Vertex M sample lines. Analyzers
equipped with option 1295-0510 detect a pneumatic
signal from valves installed at the end of the sample
line. Any leak in the tubing will cause a change in the
signal and will be detected. This test is performed
automatically as a line integrity test (LIT). This new
test complements the ability of all Vertex M analyzers
to detect blocked sample lines.
The Line Integrity Test Option requires a minimum
software revision of 1.21.1 and configuration of
analyzer software by a Honeywell Analytics Field
Service Engineer.
Pneumatic Overview
The pneumatic design of the Vertex M rack is
summarized in
Figure H-1 . The Vertex M analyzer
contains eight sample pressure transducers, one for
each point. The external tubing is terminated with a
filter and a check valve. The check valve will not permit
any flow until a “cracking” pressure of about 1.0 in. Hg
is applied. (see
Note: on page H-2 ) A leak between the
analyzer and the check valve will result in an increase
in pressure at the analyzer.
Before the LIT test can be performed, the Vertex M
and the external plumbing must be “characterized”.
This process involves measuring the sample pressure
when the tubes are known to be leak-free and otherwise
correct. It is possible to confirm that a tube is leak-free
by plugging the end and observing the sample flow
decrease to zero. During the characterization process,
the Vertex M records the observed sample pressure.
Later LIT tests will issue a fault if the sample pressure
increases significantly. Performing the characterization
without a leak check invalidates the LIT.
Note:
In this document all pressures are given in inches
of mercury. This may be converted to kilopascals by
multiplying by 3.38. Furthermore, all pressures are
reported as gauge pressure, not as vacuum. Using
this nomenclature, the effect of a sample line leak
is described as a pressure increase instead of a
vacuum decrease.
Figure A-1.
Simplified Pneumatic Schematic
In practice, the sample pressure measurements are
made as a differential measurement with the pump
on and then off. This eliminates the effect of any
transducer offset. However, since analyzers share a
pump, performing the LIT requires that all analyzers
stop monitoring. Pressures throughout the Vertex M
are allowed to stabilize for 30 seconds before taking