Baker Hughes Panametrics AquaTrans AT600, User Manual

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AquaTrans™ AT600 User’s manual 77
Chapter 5. Error codes and troubleshooting
5.1.2.6 E6: Cycle skip
Problem: The fluid acceleration exceeds the limits programmed in the program > advanced > error limits
acceleration menu.
Cause: This condition is usually caused by poor flow conditions or improper transducer alignment.
Action: Refer to “Diagnostics” on page 77, to correct any flowcell and/or transducer problems.
5.2 Diagnostics
5.2.1 Introduction
This section explains how to troubleshoot the AT600 if problems arise with the electronics enclosure, the flowcell, or
the transducers. Indications of a possible problem include:
• Display of an error message on the LCD display screen, Vitality PC software, or HART.
• Erratic flow readings
• Readings of doubtful accuracy (i.e., readings that are not consistent with readings from another flow measuring
device connected to the same process).
If any of the above conditions occurs, proceed with the instructions presented in this section.
5.2.2 Flowcell problems
If preliminary troubleshooting of an error code display indicates a possible flowcell problem, proceed with this
section. Flowcell problems fall into two categories: fluid problems or pipe problems. Read the following sections
carefully to determine if the problem is indeed related to the flowcell. If the instructions in this section fail to resolve
the problem, contact Panametrics for assistance.
5.2.2.1 Fluid problems
Most fluid-related problems result from a failure to observe the flow meter system installation instructions. Refer to
Chapter 2, 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:
•
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 AT600, excessive
amounts of solid or gas particles will absorb or disperse the ultrasound signals. This interference with the
ultrasound transmissions through the fluid causes inaccurate flow rate measurements. In addition,
temperature gradients in the fluid may result in erratic or inaccurate flow rate readings.
• The fluid must not cavitate near the flowcell.
•
Fluids with a high vapor pressure may cavitate near or in the flowcell. This causes problems resulting from
gas bubbles in the fluid. Cavitation can usually be controlled through proper installation procedures.
• The fluid must not excessively attenuate ultrasound signals.
•
Some fluids, particularly those that are very viscous, readily absorb ultrasound energy. In such cases, an E1
error code message appears on the display screen to indicate that the ultrasonic signal strength is
insufficient for reliable measurements.
• The fluid sound speed must not vary excessively.
•
The AT600 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 exceeds the limit programmed into the AT600, will result in erratic or
inaccurate flow rate readings. Refer to Chapter 3, Initial setup and programming, and make sure that the
appropriate sound speed limit is programmed into the meter.