Torque Meter Frequently Asked Questions

Even when the shaft is rotating under no load, the frequency characteristics of the detector and display, along with the friction torque of the detector, can cause a number to appear on the torque display. N-0 correction corrects this deviation, enabling more accurate measurements.

Before shipment, matching adjustments are performed using electrical components such as resistors. The FACTOR (phase difference - torque proportionality coefficient), N-0 characteristics, and overall accuracy are checked, and a test report with these values is attached. The accuracy with N-0 characteristic correction OFF is ±0.5% of the torque detector's rated torque (excluding MD series torque detectors), and the accuracy with N-0 characteristic correction ON is ±0.2%.

The N-0 characteristic is affected not only by the torque sensor itself, but also by the mechanical loss (torque) if there is a mechanical load such as a speed reducer in the measurement mechanism, which also changes with rotational speed. In addition to measuring the N-0 characteristic of the torque sensor itself, measuring the N-0 characteristic including these factors and correcting it will allow for more accurate measurements. Furthermore, the N-0 characteristic changes depending on the type and length of the signal cable, so it is necessary to use the specified dedicated cable.

To measure the N-0 characteristic, disconnect the coupling at the point you want to be unloaded. If using a torque detector alone, disconnect the coupling on the load side of the detector. Next, rotate the detector from the drive side and record the torque display value for each rotation speed. Measure both CW and CCW. By setting this value in the N-0 characteristic correction function, the display will be corrected to zero under no load conditions, regardless of rotation speed. Please note that you will need to measure the rotation speed using a TS series display. For operation details, please refer to the TS series instruction manual, "N-0 characteristic correction function".

(Example of N-0 correction settings)
We will measure the N-0 characteristics in the CW direction. Prepare a table like the one below, and rotate the detection axis with a motor or similar device under no load, recording the torque display value for each rotational speed.

≪Caution≫
In the count field, enter a number that ignores the decimal point of the displayed value, just like with the zero value. The rotation speed should also be a number that ignores the decimal point of the displayed value.

(Note) The count is, for example, if the torque display value is 34.56 Nm, then 3456 is the count.

Next, create a graph with the horizontal axis representing rotation speed and the vertical axis representing the "count value," and determine the "correction" points.

It is thought to have a frequency response like the dashed line shown. By approximating with a straight line using four correction points, you can select No. 1 to No. 4. In the case of the figure above, if you take more detailed data around 2000 r/min, where the change is large, you can make finer corrections.
The TS-2700 calculator has a maximum of 5 positive points, while the TS-3200 calculator has a maximum of 10 positive points. Note that some older TS series calculators do not have an N-0 correction function; please check the instruction manual.