strain gauge load cell wiring

Start with a simple resistance check using a multimeter. Measure between excitation leads — you should see the input resistance listed on the datasheet (often around 350Ω or 700Ω). The signal leads should show a similar value. A mismatch or open circuit means wrong pairing or a damaged gauge. Then power up and check the signal output at zero load; it should be close to zero millivolts per volt.

A 4-wire load cell has only excitation and signal pairs. A 6-wire adds a sense pair that reads the actual voltage reaching the bridge. This lets the instrument adjust for voltage drop in long cables. For short runs under 10 meters, 4-wire is fine. Beyond that, especially in outdoor monitoring, 6-wire gives you a more stable reading as temperature and cable resistance change.

Drift often comes from moisture ingress, poor connections, or temperature effects. Check the junction box seals first — even tiny amounts of condensation can cause leakage currents. Also verify that the shield is grounded only at one end. If the drift follows a daily temperature cycle, the cable resistance might be changing; a 6-wire connection can help.

Yes, but do it carefully. Use high-quality shielded instrumentation cable, and keep the splice clean and dry. Soldered and heat-shrunk joints work best. After extending, re-calibrate or at least verify the zero and span with a known weight. The longer the run, the more you will appreciate a 6-wire setup.

First, check the excitation voltage at the load cell terminals. If it is missing, trace the wiring back to the indicator or power supply. If excitation is present but no output, temporarily disconnect the signal wires and measure resistance across them at the load cell — a reading close to the rated output impedance means the bridge is intact, and the problem might be a broken conductor or a faulty instrument input.