How do I orient my load cells for installation?

Our contractor has installed several load cells upside down, is this a problem? We are also installing some Advantage load point assemblies and would like to know what is the correct orientation?

Hardy Process Solutions can provide local field service in the continental U.S. Call us to schedule a visit for regular maintenance and/or calibration services, or if you need emergency service on your weighing systems.  We can install your load cells right the first time.  Attached are two pictures that show one example of three load cell on a round vessel.  One drawing of the same tank with the load cell improperly installed.  (tangentially)

Mounting compression load cells upside down will prohibit your system from functioning properly. If the load cell is mounted upside down you will receive a negative signal voltage. The most weight controller must see a positive signal voltage to register weight. The HI 3030 controller has a setting allowing +/- millivolt signals, for use with pressure transducers.  The negative signal will not sum correctly with the positive signals from the correctly mounted load cells, and your system will not be accurate. You should remove and reinstall correctly.  Just reversing the signal or excitation wires will not insure the load cell is weighing correctly.  Load cells are tested in a single direction.  Using that load cell in the wrong direction could cause errors in the weighing. 

The exception is tension load cells.  The tension load cell will provide a positive millivolt signal mounted in ether orientation.  The cable side of the tension load sensor must be attached to the base.  The other end is the weighing section.  The difference is with the cable attached to the load cell's weighing end, the cable interferes and can add and subtract weight when installed upside down.

You should also be concerned that the load cells are level with each other (within +/- 1/32 inch), and level on it's mount +/-0.5 degrees or better.

90% of your scale accuracy is determined by the quality of the installation.

If you are installing Advantage load Point Assemblies you will have three physical mount types, Fixed, Bumper and Slider. Each mount is designed for a specific job. The shape of the Advantage load cell makes it very difficult to install upside down.  Install the load point set so they are evenly spaced around the vessel.

The FIXED load point mount allows the vessel to rotate left or right in a 360 degree arc, but it does not allow any back and forth or side to side movement. This load point can be orientated in any direction.

The BUMPER load point mount should be positioned directly across from the Fixed mount and orientated to limit the left and right rotation and allowing expansion away or towards the fixed load point. Notice the rectangular (bumper) bars mounted to the loading plate. Using the load point cable as a pointer, the cable should be orientated to point directly at or away from the fixed load point location.

CAUTION: Failure to properly orientate the Bumper load point assembly can result in the vessel falling off the load pint mounts.

The SLIDER load point mounts support all remaining legs, allowing movement for expansion and contraction in all directions. The slider load point can be oriented in any direction.

When installing load point cabling, it is very important to consider equipment and personnel traffic that may snag or damage the load cell wires.

When installing the high capacity load points the orientation may be affected by the check links and support requirements.

When installing the Advantage Lite series orientation is less important and there is some leeway in load cell to load cell orientation.  Evenly spaced is the first rule and then keeping load cell cables out of personnel walk ways and pinch points.

For additional information and examples review the attached and/or the installation manual