
Installation
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2.4 Installation Considerations
• Use proper grounding by connecting the upper supporting plate to the lower supporting plate with copper wire, then
connect all the upper plates to the grounding system.
• For optimal functioning of the system, it is necessary to connect the transmitter, load cells, junction box and weighing
structure to a single point ground. Ground the transmitter terminal 26 (SHD) to the earth ground of the system.
• Use conduit to protect the load cell cables.
• Use a waterproof junction box to extend load cell cables or to sum the load cells.
• Load cell cables must have their own conduit and be run as far as possible from any power cables.
• Load cell cables must be shielded separately from high voltage lines to reduce electrical interference when passing
through troughs containing other cables.
• Use RC filters (Quench Arcs) on relays and control switches.
• The board installer is responsible for securing the electrical safety of the instruments (fuses, door-locking switch, etc.).
Avoid welding near load cells.
2.5 Mechanical Installation Check
1. With a voltmeter, measure the load cells excitation supply on the terminals 1 and 2 to read the actual 10 VDC
excitation value.
2. When the scale is empty measure the signal in mV on the terminals 3 and 4.
3. Put a calibration weight on the scale and measure the signal in mV again.
Make sure the signal increase corresponds to the result of the following equation:
mV Total/ FS Capacity = mV Change/ Cal Weight
•mV Total is excitation voltage x mV/V rating of load cells
•FS Capacity is load cell capacity x number of load cells
•mV Change is the millivolt change when the weight is applied
•Cal Weight is the amount of test weight
Example – Assume there are four 2,500 lb load cells for an FS Capacity of 10,000 lb
With a calibration weight of 1,000 lb, the signal increases to 2.0 mV
4. If the value in mV is correct and the output signal is wrong move on to Calibration (Section 3.0 on page 5).
5. If the value in mV is lower than the calculated value move on to the Load Cell Verification.
6. If the value in mV is greater than the calculated value move on to the Load Cell Verification.
If problems exist after completing the installation check, please call Rice Lake Weighing Systems for support.
mV Total =mV Change
FS Capacity Cal Weight
20 mV =XX = 20,000 X = 2.0 mV
10,000 lb 1,000 lb 10,000