Eagle Microsystems LCWA-LO - Manual (Page 2)

LC-WA LO IB.doc
9/16/04
2. Load the tank with a known weight and check the Weight Indicator reading.
3. Check the tank corner loading by applying a known load to each leg.
B. The Weight Indicator readings drift rapidly:
1. Check for water in the Load Cell Junction Box.
2. Check for a damaged load cell cable.
3. Check for a damaged load cell.
4. Check the Weight Indicator with a load cell simulator or a good load cell to
verify that the Weight Indicator is working correctly.
SERVICE INFORMATION
A. Load Cell resistance test:
1. Disconnect the load cells from the Junction Box and measure the resistance as
shown in figure 1.
2. Any leakage between the leads and the load cell case is usually caused by water
leakage into the cell or by water in a damaged load cell cable.
3. If a load cell does not pass the above resistance tests, replace it with a known good
one.
B. Load Cell zero shift test:
1. Remove load cell from Weigh Assembly.
2. Connect a DC power supply of 10 to 15 volts to the Red (+) and Black (-) load cell
leads.
3. The measured output between the Green (+) and White (-) leads should be less
than 5 millivolts.
4. An output signal greater than 5 millivolts indicates a zero shift caused by mechanical
overload.
5. If the output signal is between 5 and 15 millivolts, the load cells zero has shifted,
but will probably still continue to work.
6. If the output signal is greater than 15 millivolts, the load cell should be replaced with a
known good one.
NOTE: If the load cell's zero has shifted due to a mechanical overload, the reason for the
over load should be determined before new load cell is installed.