Rice Lake Combination System - Precision Loads On-Board Weighing Systems - Manual (Page 53)

Service and Troubleshooting 49
5.0 Service and Troubleshooting
5.1 System Maintenance
This section of the manual is intended to assist the user with techniques for system maintenance and
troubleshooting. Maintenance of the on-board scale is very simple but needs to be done at regular intervals. For
service issues make sure you have original test numbers to work with, as these test numbers help locate a problem
source quickly. Scale meters are built with very simple but effective internal system diagnostics programs that
isolate component performance.
With reference to on-board scale service and repair procedures that involve load cells, load pins, trunnions and air
transducers, some fundamental precautions and recommendations must be observed by servicing personnel:
• Servicing personnel must ensure that all vehicle structures are free from cracks, excessive wear, corrosion,
alignment problems, etc. that can affect safety and scale performance.
• The instructions outlined herein are designed to ensure that a properly serviced installation will provide
maximum safety, optimum system performance and accuracy, and a long operating life. It is therefore
extremely necessary that the installer comply with all guidelines and material specifications outlined in this
manual, with special emphasis on detail and inspection of work.
• Service and repair work must be in compliance with appropriate regulations of the U.S. Department of
Transportation (DOT), state and local regulations, the recommended standards and practices of the Society
of Automotive Engineers (SAE), standards of the American Welding Society (AWS), and the
recommendations of the truck, trailer and body, hoist and/or suspension manufacturer.
WARNING
Failure to observe these recommendations and instructions could result in a hazardous operating
condition.
Maintenance of the On-Board Scale System typically consists of just a few functions, which should be performed
at regular cycles.
5.2 Calibration
System calibration needs to be performed at the time of original scale installation. Rice Lake Weighing Systems
recommends that scale calibration be repeated about one month after original scale installation to adjust for any
mechanical influences that "seat" a new scale.
There is no typical interval for scale calibration that can be universally specified. Instead, operators should keep
comparison data of on-board scale loads as compared to weights obtained from certified platform scales or
pre-measured loads. If this is not possible, six-month re-calibration intervals are recommended.
5.3 Sensor Maintenance
5.3.1 Load Cells
For all bolt-down load cells, it is critically important that all mounting and locating bolts have their recommended
torque values maintained at specified values. Torque values in lb/ft and Nm are shown in “Bolt Torque Values” on
page 58. In addition to load cell bolt torque values, service personnel must also monitor the torque values of bolts
used to mount load cell bracketry. For load cell bolts, which mount with coil springs, ensure that bolt tightening
compresses the coil by at least 0.25 inch, and that a serviceable bolt thread locking material is used (See
Section 5.7.1 on page 52).
5.3.2 Load Pins
For hinge pivot and ram-mount load pins, thorough pin lubrication is critical to proper scale performance. Ensure
all load pins used in roll-off, dump body, waste water tank and other pin applications are always well-lubricated.
5.3.3 Visual Inspection
At the end of each day, service personnel should perform visual inspections that look for: signs of wear or
"polishing"; any sign of weld cracking or failure; any evidence of excessive corrosion; evidence of potential
chassis, body runner or support structure cracking or bending. When the RLWS load cells were originally installed,
instructions specified that mounting brackets required clean, flat, rigid and co-planar surfaces for welding. If these
surfaces have become cracked, corroded or out of alignment, then corrective action must be taken to ensure proper
performance and safety of the on-board scale installation.