diagram 4 wire load cell wire connection

There’s no universal standard, so always check the manufacturer’s datasheet. A common arrangement is red for Exc+, black for Exc–, green for Sig+, and white for Sig–, but it can be different. If you don’t have the sheet, measure resistance between leads. The pair with lower resistance (often 350Ω or 1kΩ) is the excitation pair; the other is the signal pair. Connect the excitation leads to your power supply first, then verify the signal polarity with a small test weight.

Drift can come from several sources. First, check that the shield wire is connected at one end only (usually the amplifier). If both ends are grounded, a ground loop can inject noise. Second, make sure you’re using the correct excitation voltage—overexciting can heat the strain gauges and cause drift. Third, look for moisture in the connector or junction box; even slight corrosion can create leakage paths. If the cell is new and these steps don’t help, contact Kingmach’s support for troubleshooting.

Yes, but you’ll introduce voltage drop in the excitation leads, which slightly reduces the sensitivity. For short extensions (a few meters), the error is usually negligible if you’re within the amplifier’s tolerance. For longer runs, consider switching to a 6-wire configuration where two sense leads compensate for the drop. When extending, keep the splice shielded and watertight. Kingmach can supply pre‑wired extension cables that match their load cell color codes to reduce mistakes.

Most likely the signal polarity is reversed. Swap the two signal wires (Sig+ and Sig–) at your amplifier input. If the reading becomes positive, you’ve flipped polarity. A small zero offset is normal; many instruments have a zero/tare function to eliminate it. If the offset is very large, check for a damaged load cell cable or terminal block by measuring the signal voltage at zero load—it should be close to zero millivolts relative to the excitation.

You’ll need a summing junction box. Inside it, each load cell’s excitation leads connect in parallel to the power supply (maintaining Exc+ and Exc–), and each signal pair connects through a summing network to provide one averaged Sig+ and Sig– to the amplifier. Make sure all load cells have the same rated output and capacity, and keep the wiring symmetrical to avoid angle errors. Kingmach offers junction boxes with built‑in trimmers for corner balancing.