21
Problem
Description
Solution
Small Amplitude Changes
or Erratic Fluctuations in
Display Readings
Fluctuations in readings can be caused
by problems with signal processor.
Check signal processor excitation voltage and
incoming AC voltage for accuracy and stability
(refer to signal processor manual).
Repeatable Drift over
24-hour Period
Periodic drift is most likely caused by
thermal expansion due to sun’s radia-
tion or vessel’s response to its own
heating cycles.
Problem likely to be noticed shortly
after initial installation or on system
that previously functioned correctly in
cool or overcast weather.
Loosen nuts on top bolts and inspect top bolts.
· Top bolts free to move in their holes: If vessel
is heated, it may be radiating or conducting
heat through vessel legs and affecting Load
Stand
®
sensors.
· To reduce head radiation/conduction:
a) Insulate vessel.
b) Use a heat shield like a metal plate to
reflect heat.
c) Contact Anderson-Negele to discuss adding
a high temperature insulating pad.
· Top bolts jammed—Jammed top bolts indicate
undersized bolt holes on vessel mounting
flange and/or vessel support movement
beyond limits of Load Stand
®
clearance
holes. Resulting side loads affect Load Stand
®
sensors.
· To reduce side loads:
a)
Enlarge vessel mounting flange bolt holes
to provide additional clearance.
If support movement and heat radiation/con-
duction have been eliminated as source of error
and periodic drift still indicates system is not
meeting specifications (Appendix A), contact
Anderson-Negele.
Note:
If keeping long-term records, take
level readings at same time each day to
minimize error.
Troubleshooting Load Stand
®
II
Problem
Description
Solution
Sudden Change in Weight
Reading or System
Requires Frequent
Recalibration
Sudden change in weight reading can
be caused by a broken Load Stand,
causing indicated weight to shift up or
down by large amount, up to 100 % of
full-scale live load.
Problem likely to be noticed on system
that previously functioned correctly.
Check voltage outputs of individual Load Stands
(refer to Chapter 2, Pre-Check Procedures, the
section titled Method 1: Measuring Output).
Voltage should be between -750 mV and +750
mV on installed Load Stands. If not, check Load
Stand
®
resistance as described above in
Problem 1.
Sudden change in weight reading can
be caused by problems with signal
processor.
Check signal processor excitation voltage and
incoming AC voltage for accuracy and stability
(refer to signal processor manual).
Summary of Contents for Load Stand II
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