March 2004
6-6
Error Codes and Diagnostics
Fluid and Pipe
Problems
If preliminary troubleshooting with the
Error Code Messages
and/or
the
Diagnostic Parameters
indicates a possible problem, proceed
with this section. Measurement problems fall into two categories:
•
fluid problems
•
pipe problems.
Read the following sections carefully to determine if the problem is
indeed related to the fluid or the pipe. If the instructions in this section
fail to resolve the problem, contact GE Panametrics for assistance.
Fluid Problems
Most fluid-related problems result from a failure to observe the
flowmeter system installation instructions, as described in Chapter 1,
Installation
. Refer to Chapter 1,
Installation,
to correct any
installation problems.
If the physical installation of the system meets the recommended
specifications, it is possible that the fluid itself may be preventing
accurate flow rate measurements. The fluid being measured must
meet the following requirements:
1. The fluid must be homogeneous, single-phase, relatively clean and
flowing steadily.
Although a low level of entrained particles may
have little effect on the operation of the Model UTX878,
excessive amounts of solid or gas particles will absorb or disperse
the ultrasound signals. This interference with the ultrasound
transmissions through the fluid will cause inaccurate flow rate
measurements. In addition, temperature gradients in the fluid flow
may result in erratic or inaccurate flow rate readings.
2. The fluid must not cavitate near the measurement point.
Fluids
with a high vapor pressure may cavitate near the measurement
point. This causes problems resulting from gas bubbles in the
fluid. Cavitation can usually be controlled through proper system
design.
3. The fluid must not excessively attenuate ultrasound signals.
Some fluids, particularly those that are very viscous, readily
absorb ultrasound energy. In such a case, an
E1
error code
message will appear on the display screen to indicate that the
ultrasonic signal strength is insufficient for reliable measurements.
4. The fluid sound speed must not vary excessively.
The Model UTX878 will tolerate relatively large changes in the
fluid sound speed, as may be caused by variations in fluid
composition and/or temperature. However, such changes must
occur slowly. Rapid fluctuations in the fluid sound speed, to a
value that is considerably different from that programmed into the
UTX878, will result in erratic or inaccurate flow rate readings.
Refer to Chapter 2,
Programming Site Data
, to make sure that the
appropriate sound speed is programmed into the meter.
Summary of Contents for UTX878 Ultrasonic
Page 2: ...iii March 2004 The UTX878 Flow Transmitter and Transducers ...
Page 8: ...Chapter 1 ...
Page 20: ...March 2004 Installation 1 11 Figure 1 5 UTX878 Outline and Installation Dwg 712 1196 rev 2 ...
Page 22: ...March 2004 Installation 1 13 Figure 1 7 UTX878 Wiring Diagram Dwg 702 528 rev 2 ...
Page 23: ...Chapter 2 ...
Page 45: ...Chapter 3 ...
Page 52: ...Chapter 4 ...
Page 60: ...Chapter 5 ...
Page 65: ...Chapter 6 ...
Page 75: ...Chapter 7 ...
Page 80: ...Appendix A ...
Page 85: ...Appendix B ...
Page 86: ...CE Mark Compliance Introduction B 1 EMC Compliance B 1 ...
Page 88: ...Appendix C ...
Page 89: ...Data Records Site Data C 1 ...
Page 93: ...Appendix D ...
Page 94: ...Service Record Introduction D 1 Data Entry D 1 Diagnostic Parameters D 3 ...