How to Calibrate Load Cell Transmitter?

We covered how to calibrate the load cell and connect it to the load display in our previous blog. In the process of using the sensor, sometimes we need the standard analog signal of the sensor, so we need a transmitter to convert the mV signal of the load cell into standard industrial signals, such as 0-20mA, 4-20mA, 0-10V, etc. ATO load cell transmitter is the protagonist of our introduction, its output signal is 4~20mA.

Preparation work:

We use a load cell with a range of 100kg (1kN) for this experiment, and first connect the four wires of the sensor to the transmitter. The load cell transmitter is powered by 24V DC, and the 4~20mA signal output ports are P- and I.

Connect the detection instrument to the transmitter.

Power on, the red light of the transmitter is on, and the current display current is 3.57mA.

Calibration

Step 1:

Adjust ZERO to make the current value close to 0 (0.01mA). It is calculated that a 2kg weight corresponds to an output current of 0.32mA (in actual use, the weight of the calibrated weight should be 50%~100% of the sensor range).

After placing the weight on the sensor, the current shows 0.45mA.

Step 2:

Adjust SPAN so that the current output value is close to 0.32mA.

Take off the weight and the current output value was observed to be around 0.01 mA.

Step 3:

Adjust ZERO to make the current output value equal to 4.00mA. After putting the weight on, the output current display value is about 4.33mA, with a calibration error of 0.01mA.

With regard to eliminating errors, in actual calibration we should use the maximum capacity weight that is as close to the sensor as possible. The above is a graphic introduction. For more details, you can watch the YouTube video below.