Load Cell Amplifier Suddenly Showing 0 Reading

Hello,
I’ve been using a Digital Load Cell Amplifier RS485 (ATO-LCTR-OAR) together with a Tension and Compression Load Cell 50 kg (ATO-LC-TC01). The setup has been running perfectly for months, but suddenly, yesterday, the amplifier started showing only 0 on the display.
Has anyone experienced this before? Could this be a load cell issue or something wrong with the amplifier itself? Thank you in advance.

Auberon wrote:
Hi Auberon,
1. Please check the wiring first. The issue might be caused by loose connections.
2. The sensor might have been damaged due to overload. You can test the load cell condition as follows:
2.1 Locate the connection terminal of the sensor on your amplifier. The red and black wires (EX+, EX–) are the excitation voltage, normally around 5V.
2.2 Disconnect the green and white signal wires (SIG+, SIG–) while the sensor is unloaded.
2.3 Set your multimeter to mV range, then measure the voltage between the green and white wires.
2.4 If the voltage is below 0.3mV, gently press the sensor — if the value changes clearly, the sensor is good.
2.5 If the voltage exceeds 0.3mV and doesn’t change under pressure, the sensor is likely damaged.

Thanks for the detailed steps. I just tested it — when measuring between SIG+ and SIG–, I get 1.1V, and it doesn’t change at all when I apply force. Seems like the sensor is dead.

Auberon, I had a similar issue once — turned out it wasn’t the load cell but a broken solder joint on the amplifier’s input terminal. You might want to inspect the connector or re-tighten the screw terminals before replacing anything.

Also, don’t forget to check if the shield wire is properly grounded. I once got all-zero readings because of electrical noise and poor grounding on the amplifier side. After fixing that, it started working again.

Auberon wrote:
1. Please let us know the actual load weight you applied to the sensor. If it exceeded the 50 kg range, overload damage could be the cause. In that case, we recommend replacing it with a higher-capacity model.
2. The recommended excitation voltage for our load cell is DC 5–15V, ideally 10V for the best stability.

Appreciate the suggestions! I’ll double-check the wiring and grounding, but based on the constant 1.1V reading, it really seems like the sensor is gone. I’ll follow ATO’s advice and consider a higher range unit next time to avoid overload.