Why is my C2® load cell count incorrect?

There are several reasons why you may be getting an incorrect count of the C2 devices.  These range from noise on the line, incorrect load cell wiring, or even a bad controller.

To help determine why your C2® load cell count is incorrect, try the following:

1. Check the load cell cable at the summing junction box. Verify there is a Violet (-C2) and a Gray (+C2) wire pair. If you do not find a violet and gray pair you most likely do not have the C2® calibration feature. If you do have C2® capable load sensors, verify the wires are connected to the correct load cell terminals. Verify there is a pair of wires connected from the C2® connection on the summing junction box to the weight controller load cell connector and are connected correctly.

2. The C2® load point information is only read at certain times. For the HI 2151/30WC controllers,and HI 1746 WS modules, the C2® information is read when you power up or cycle power. For the HI 1756WS, HI 1771WS and the HI 200DNWM family of Weigh Scale Modules, as well as the 3000 4000, and 6000 series units, the C2® is read during calibration.

3. Some scale systems, such as the HI Anyweigh series have only a single C2® module for the total scale. This C2® module is terminated on the weight controller's load cell connector.  This type of scale will show only one C2® module, when it really has 4 four actual load cells.  In this type of instance, the C2® count would be correct.

4. Cable noise in some load cell systems interfere with the reading of the C2® modules.

5. The C2® module may be damaged. 

Troubleshooting/correction:

If noise is the problem, installing a single 2200 pf capacitor across the C2® terminals will eliminate the problem. Install the capacitor under the C2® terminals (+ and - C2) of the TB9 connector in the summing junction box.

Connecting or disconnecting the load point connectors with power applied can damage C2® modules. Using a voltmeter, verify that there is 5 vdc at the following locations:

a. C2® terminals of the weight controller.
b. C2® terminals on the Summing junction box .
c. C2® terminals on the Load point connectors.

With power off and the load cells disconnected, use an ohmmeter to read approximately 3 Meg ohms across the individual Violet and gray wires. Reverse the meter leads and read 12 Meg ohms or higher. 

Disconnect all C2® load sensors and attach the C2® load sensors one at a time to verify operation.

Cycle power.

Check using the C2® calibration's load cell count.