Rice Lake BCi Belt Scale - Maintenance & Troubleshooting Manual - Manual (Page 10)

6 Belt Scale Maintenance Instructions
4.0 Belt Scale Troubleshooting Tips
The following section covers basic troubleshooting tips for the belt scale. If the BCi in-motion belt scale fails to
operate properly during or after performing set up and calibration, it’s suggested to perform the procedure again,
and if the problem still persists, follow the troubleshooting procedures listed in the following sections.
Calibration Shifts
Frequent calibration shifts should be isolated to zero shifts or span shifts.
Zero Calibration Shifts
Zero shifts are normally associated with the conveying system. When a zero shift occurs, the span will shift by a
like number of TPH, this then appears as a span shift.
Common causes of zero shifts:
• Material buildup on the carriage/weighbridge assembly
• Rocks lodged in the carriage/weighbridge
• Conveyor belt tracking
• Non-uniform conveyor training
• Conveyor belt belting stretch due to material temperature variations
• Trouble in the electronic measuring components
• Severely overloaded load cell
Span Calibration Shifts
Span shifts are normally associated with the electronic measuring of components of the system, with one
exception, which is conveyor belt tension. A span shift is present if both points change by the same percentage
TPH.
Common cause of span calibration shifts:
• Change in conveyor belting tension
• Speed sensor roll build-up and/or slipping
• Conveyor scale alignment
• Severely overloaded load cell
• Trouble in electronic measuring components
Field Wiring
If you suspect a problem with the wiring of the belt scale, use the following points to double check the electrical
portion of the scale.
• Check for proper interconnections between the components of the system. All the wiring must be as
specified on the installation drawings.
• Check all wiring and connections for continuity, shorts, and grounds using an ohmmeter.
• Loose connections, poor solder joints, shorted or broken wires and unspecified grounds in wiring
will cause erratic readings and shifts in weight readings.
• Check that the grounding of all cable shields is made at only the locations as specified in the
installation drawings.