SECTION
5-1
EN
5
Troubleshooting
This section provides basic troubleshooting suggestions to help solve the most
common operating problems.
FIGURE 5-1. Range of Output.
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 leak
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 an oil fill fluid leak can 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:
n
Sustained drift rate in true zero and span or operating point output or both.
n
Sluggish response to increasing or decreasing pressure or both.
n
Limited output rate or very nonlinear output or both.
n
Change in output process noise.
n
Noticeable drift in operating point output.
n
Abrupt increase in drift rate of true zero or span
or both.
n
Unstable output.
n
Output saturated high or low.
mA
3.6 for Analog
(1)
3.75 for Smart
20.8
3.9
Normal Operating Range
20
4
Hardware Alarm
Process Variable
Out of Range
Fail Low Fail High
Smart only
21.75
(1) Failure mode for output code M is
≤
1V.
(2) Above Values are for Standard
Failure Mode. NAMUR compliant
values are different than above.
4690.bk : 4690.s5 Page 1 Tuesday, May 26, 1998 5:28 PM
