Rice Lake Combination System - Precision Loads On-Board Weighing Systems - Manual (Page 15)

Applications 11
4.0 Applications
4.1 Air Pressure Transducer
• Air pressure transducer units are factory-sealed and do not contain field serviceable parts. Do not attempt to
open these units as they are internally encapsulated and breaking this seal voids warranty of the unit.
Figure 4-1. Air Pressure Transducer Units
• The model PL9000-101 assembly contains a single pressure transducer element, while the PL9000-201 is a
dual element transducer. Dual transducer assemblies can be used with either dual or single-ported leveling
valve suspensions. Dual transducer models are recommended for all tractor and straight truck applications
and for any trailer applications involving the weighing of loads on uneven (off-road) surfaces.
• If a drop axle (tag or pusher) is installed on the straight truck, tractor or trailer, check to see how the height
control valve is configured for air supply to the axle. Rice Lake Weighing Systems does not recommend
installing air pressure sensors on lift axles for most applications. Scale calibration and normal scale operation
should always be performed with the lift axle raised to achieve the most reliable readings.
• For best operating results, Rice Lake Weighing Systems recommends the use of a Haldex Immediate
Response height control valve. The Haldex model number 905-54-241 valve may be purchased from Rice
Lake Weighing Systems or through a local Haldex supplier. This valve has dual port supply to the air bags
with a rated operating pressure of 160 psi (10.9 bar). The valve adjusts air pressure with no time delay to
maintain desired chassis position.
Figure 4-2. Height Control Value (shown on side)
• Air pressure transducer kits may be used with other half system kits containing load cells and load pins.
Examples are 5th wheel load cell kits, hanger suspension load cells, trunnions and kingpin plate kits used
with air transducer half systems in 2, 3 and 4 channel full systems to provide a complete tractor/trailer
onboard scale. Load cell/pin and air sensor half systems always operate on separate indicator channels.