Load cell resistance, specifically input resistance, output resistance, and insulation resistance, is one of the most important yet misunderstood specifications in weighing systems.
These resistance values directly affect excitation voltage, signal integrity, paralleling accuracy, cable compensation, power consumption, and long-term reliability.
Our guide covers everything you need from definitions, typical values, diagnostic measurements, what impacts load cell accuracy, and field-proven best practices.
What Is Load Cell Resistance?
Every strain-gauge load cell contains a Wheatstone bridge made of four resistive strain gauges. “Load cell resistance” almost always refers to two key values on the datasheet:
Input Resistance (Excitation Impedance)
- Measured between +Excitation and –Excitation wires (usually red/black)
- Industry standards: 350 Ω (most common), 700 Ω, or 1000 Ω
- What it really means: This is the resistance the indicator or power supply “sees” when energizing the bridge.
Output Resistance (Signal Impedance)
- Measured between +Signal and –Signal wires (usually green/white)
- Almost always identical or within a few ohms of input resistance in full-bridge cells
- Typical: 350 Ω for 350 Ω cells, ~700 Ω for high-resistance cells
Higher resistance (700–1000 Ω) cells draw less current, ideal for battery-powered or wireless systems and very long cable runs.
Standard Load Cell Resistance Values by Type
Not all load cells are built the same, and their resistance values vary based on how and where they are used.
The table below shows the most common resistance ranges you will see in real-world applications and what types of systems they are typically used for.
Knowing these typical values helps you quickly spot whether a load cell is correctly specified or if something looks off during troubleshooting or system design (always consult with the manufacturer).
| Load Cell Type | Input Resistance (Typical) | Output Resistance (Typical) | Common Applications |
|---|---|---|---|
| Standard foil gauge | 350 Ω ±3–5 Ω | 350 Ω ±1 Ω | Platform, bench, truck scales |
| Precision / Certified | 350 Ω ±0.5 Ω | 350 Ω ±0.1 Ω | Legal-for-trade, process weighing |
| Low-power / Wireless | 700 Ω or 1000 Ω | ~700 Ω or ~1000 Ω | Remote, battery, telemetry systems |
| Shear beam, S-type, canister | Usually 350 Ω | Usually 350 Ω | Industrial standard |
How to Properly Measure Load Cell Resistance
Measuring load cell resistance is one of the fastest ways to check the health of a weighing system.
With just a multimeter and a few minutes, you can identify wiring issues, moisture damage, broken strain gauges or failing insulation before they cause serious accuracy problems.
The checks below are listed in a practical order and reflect what technicians use in the field every day.
Wiring diagrams below are typical color coding, always consulted to manufacturer specifications.
| Measurement | Wires (Color) | Good 350 Ω Cell Value | Red Flag |
|---|---|---|---|
| Input resistance | Red – Black | 350–410 Ω (commonly ~400 Ω) | <300 Ω or >1000 Ω |
| Output resistance | Green – White | 348–352 Ω | >355 Ω or <340 Ω |
| Insulation resistance (wires to shield/body) | Any wire → Shield | >5 GΩ (ideally >20 GΩ) | <1 GΩ = failing, <100 MΩ = replace |
| Individual wire to shield (each of 4) | Each wire → Shield | >5 GΩ | Any <1 GΩ indicates cable damage |
| Bridge balance (pro diagnostic) | Red→Green, Red→White, Black→Green, Black→White | All within 0.5–1 Ω of each other | >3–5 Ω difference = damaged gauge |
- Note: Many 350 Ω load cells actually have a load measurement of around 380–405 Ω input because manufacturers add small compensation resistors.
Best Practices to Eliminate Resistance-Related Errors
Even the best load cell can deliver poor results if the system around it is not designed correctly. Most resistance-related weighing errors are not caused by the force sensor itself, but by cabling choices, wiring methods, or small mismatches that add up over time. The best practices below are simple, proven steps that help eliminate these issues and protect long-term accuracy in real-world operating conditions:
- Use 6-wire + remote sense for any cable >10 m or accuracy >0.02 %.
- Match input resistance within ±0.5 Ω when paralleling load cells.
- Use shielded, twisted-pair cable and sealed junction boxes in wet environments.
Make Load Cell Resistance Work for You, Not Against You
Load cell resistance itself is not the enemy, uncontrolled variation and ignorance of its effects are. A modern 6-wire system with properly matched, high-insulation-resistance load cells removes virtually every resistance-related error source, leaving only the inherent non-linearity and temperature coefficients of the cell itself as accuracy limits.
Perform the five quick resistance checks above on every new installation and during annual maintenance. Catch problems early, design the cabling right the first time, and your weighing system will deliver repeatable accuracy for years.
Master load cell resistance, and you master weighing accuracy.
Need Help Optimizing Your Weight Measurement System?
Massload works with industrial scale equipment to ensure proper load cell selection, accurate calibration, and long-term system reliability. Our team supports new installations and existing systems, helping eliminate resistance-related errors and protect measurement accuracy.
Contact Massload today to discuss your scale, calibration needs, and weighing equipment requirements.
