Emerson Rosemount 3095, Reference Manual, Page: 111 / 130

Reference Manual
00809-0100-4716, Rev JA
May 2008
5-5
Rosemount 3095 MultiVariable
Unexpected Process
Variable (PV) Readings
The EA software provides a means to display the current process variables
and flow calculations.
WARNING
The following performance limitations may inhibit efficient or safe operation.
Critical applications should have appropriate diagnostic and backup systems
in place.
Pressure transmitters contain an internal fill fluid. It is used to transmit the
process pressure through the isolating diaphragms to the pressure sensing
element. In rare cases, oil loss paths in oil-filled pressure transmitters can be
created. Possible causes include: physical damage to the isolator
diaphragms, process fluid freezing, isolator corrosion due to an incompatible
process fluid, etc.
A transmitter with oil fill fluid loss may continue to perform normally for a
period of time. Sustained oil loss will eventually cause one or more of the
operating parameters to exceed published specifications while a small drift in
operating point output continues. Symptoms of advanced oil loss and other
unrelated problems include:
• Sustained drift rate in true zero and span or operating
point output or both
• Sluggish response to increasing or decreasing pressure or
both
• Limited output rate or very nonlinear output or both
• Change in output process noise
• Noticeable drift in operating point output
• Abrupt increase in drift rate of true zero or span or both
• Unstable output
• Output saturated high or low.