Fault-Tracing Procedure - ABB PFEA 111 User Manual

6.5 Fault-tracing Procedure

3BSE029380R0101 Rev C
Faults in the...
Mechanical installation
Load cells
Cabling
Tension Electronics
(1) Read more about the overload capacity for your load cell type in Appendix B, C, D, E, F or G.
Tension Electronics PFEA111/112, User Manual
Section 6.5 Fault-tracing Procedure
Fault symptoms
Faults in the mechanical installation usually manifest
themselves as an unstable zero point or incorrect
sensitivity.
If a fault is associated with a process parameter, such
as the temperature, or can be linked with a particular
operation, the fault is likely to emanate from the
mechanical part of the installation.
Calibration data for a load cell do not change
gradually. A load cell, depending on its size and type,
can withstand up to five times
the measuring direction. An event in the process line,
such as web breakage, may cause an overloading
large enough to alter load cell data. Depending on the
amount of overload, it may be sufficient to zero set.
Problems such as malfunctions or unstable zero point
may arise from faulty cables or wiring.
Proximity to noisy cables may cause interference
problems.
Incorrect installation, such as cable cores connected
asymmetrically or screens earthed at both ends
instead of only at one end, may show up as an
unstable zero point.
If the polarity of load cell signals is not correct,
the cabling has to be checked.
Intermittent loss of a function is usually due to a fault
in the tension electronics.
Instability problems seldom originate from the tension
electronics.
Faults in devices connected to the tension electronics
may affect its operation.
(1)
the nominal load in
6-3