# Transducers FAQ

## Transducers

• What order should transducer cables be connected in?

Our transducers have input as red-black and output as white-green. To connect to instrument terminals, connect in the order of A-red, B-green, C-black, and D-white (the same applies to the bridge box SB-121A). Also, for bridge box (SB-120B) and 8-pin type, connect in the order of "red, green, black, white" to 1, 2, 3, and 4, while referring to the wiring diagram shown next to the bridge box.

• Please describe the method for setting the calibration coefficient.

The calibration coefficient is capacity ÷ rated output (×10-6).
For example,
for a displacement transducer with a capacity of 50 mm and rated output of 5000 (x 10-6), the calibration coefficient is 50 mm ÷ 5000 = 0.01.
Although the setting method differs depending on the instrument,
for TDS-303/TC-31K, set coefficient 1.000 point 2
for TDS-530/-540/-630/-602/TC-32K, set coefficient +1.00000E-02 point ####.##.

Our products indicate negative compression loads. Depending on the type of indicator used, only the positive side is be displayed. If this type of indicator, the polarity of the output can be reversed by reverse-connecting the "green" and "white" cables.

• What is the deformation of a load cell when a load is applied?

It depends on the type of load cell. For example, CLP-30KNB has a deflection of 0.05 mm at a rating of 30 kN.

• What is the frequency response of load cells?

It depends on the type of load cell. For example, CLP-30KNB has a natural frequency of approximately 11 kHz. Generally, the frequency response is 1/10 of the natural frequency, so the frequency response is 1.1 kHz.

• What is the frequency response of pressure transducers?

In the case of a flush diaphragm type, it is about 1/10 of the natural frequency.
For example,
the natural frequency of PWFC-10MPB is 130 kHz, so the frequency response is 1/10 of that at 13 kHz.
Note, however, that if the pressure transducer is installed such that it is in direct contact with the pressure medium and an introduction pipe is used, the frequency response will be significantly lower due to resonance with the introduction pipe.
A pressure gauge for general use with a pressure cavity (PW-PA type) resonates with the inlet all the way to the pressure cavity and so is not suitable for dynamic measurement.

• Please describe the polarity of flange-type torque transducers.

Flange-type torque transducer LTB-NA outputs positive polarity when a clockwise force is applied to the flange.

If the magnitude of the force to be measured is known to some extent, it is advantageous resolution-wise to choose a load cell with a greater minimum capacity. However, in the case of fatigue use, select a load cell with double the capacity. In addition, it is common not to select a load cell with a capacity of 10 times or more the maximum value of the force to be measured.

• What does PCD in dimension drawings stand for?

This means that the specified items are arranged equally in an imaginary circle where the indicated numbers are the diameter. For example, 8-ø8.5 PCD90 means "eight holes 8.5 mm in diameter are evenly spaced on an imaginary circle 90 mm in diameter."

• Can negative pressure be measured with a pressure transducer?

Since our pressure transducers are gauge pressure gauges with zero atmospheric pressure, basically it can be measured. However, since the calibration coefficient differs from that of the positive-pressure side, a separate calibration is required. Please contact us in advance. Since the negative pressure is about 100 kPa at the maximum, resolution is lower with a high-capacity pressure transducer. The degree of vacuum cannot be measured because it is not a vacuum gauge.

• Please describe notation for rated output.

There are two units of rated output: mV/V (μV/V) and × 10-6 strain. mV/V (μV/V) represents the magnitude of the output voltage relative to the applied voltage. × 10-6 strain is displayed when the gauge factor (K) is set to 2.00 with the strainmeter. In data loggers, etc., physical quantities can be read directly by entering the calibration coefficient (listed in the test data), which is the capacity divided by this value.

• What does mutual interference mean?

Mutual interference is the specification of a transducer that measures physical quantities in two or more directions. The significance of this is that the output is displayed when the loaded to capacity in a direction other than the measured directions and divided by the rated output.

• Please describe the rated output of inclinometers.

The rated output of our inclinometers is from vertical to capacity. Therefore, the output from the negative capacity to the positive capacity is twice the rated output.

• What is the significance of temperature effect on zero?

The output of a transducer under no load fluctuates slightly due to changes in ambient temperature. This is a specification indicating the magnitude. Usually, the allowable variation per ℃ is expressed as a percentage of the rated output. If there is a temperature change during measurement, the measured value has this variation added.

• What is the significance of temperature effect on span?

The sensitivity of a transducer (the degree of change in the measured value with respect to the change in the measured quantity) varies slightly with the ambient temperature. This is a specification representing the degree of change, and is expressed in a percentage as the rate of change per 1℃. This will affect a case where the temperature at the time of calibration for obtaining the rated output (listed in the test data) is different from the operating environment temperature. For example, suppose that a load cell with a specification for temperature effect on span of 0.005%/℃ calibrated at 23℃ is used in an environment of 53℃, and a measured value of 2000 × 10-6 is obtained. Since 2000×10-6 × 0.00005 × (53-23) = 3×10-6, this measured value includes an error of up to ±3×10-6.

Zero balance is the output of a transducer when no load is applied, and many transducers are adjusted so that the value is smaller. Some displacement transducers are adjusted at around half their capacity instead of when at no-load. This applies to the following displacement transducers.

• Can transducers (sensors) such as load cells, displacement transducers, and pressure transducers be used with other companies' instruments?

If it is a strain gauge-type instrument, it can be used with other-company instruments. Read the instruction manual of the instrument carefully to confirm that can be used. However, transducer (sensor) input/output cable connections and cable colors differ with the manufacturer. Carefully refer to the connection drawings described in the transducer manual and the instrument’s operation manual.

• How is the calibration coefficient set for load cells with a remote sensing function?

On the instrument compatible with the remote sensing function, set the mode to the remote sensing mode, and enter the calibration coefficient of the load cell for the coefficient setting on the instrument.
When measuring with an instrument that does not have a remote sensing function, the rated output decreases by the resistance of the cable connected to or attached to the load cell. The correct physical quantity (load) cannot be measured unless the instrument has been set with the calibration coefficient calculated with a correction for cable resistance.

How to calculate the corrected calibration coefficient (example)
Load cell with a capacity 100 kN
Rated output 2000 × 10-6
Bridge resistance 350 Ω.
Total resistance of the connected or attached cable 1.2 Ω at 10 m.
Rated output after correction = rated output given in test data × (bridge resistance value / bridge resistance value + cable resistance value)

Example) 2000×10-6 × (350 / 350 + 1.2) = 1993 × 10-6

Since the calibration coefficient is capacity divided by rated output,
The calibration coefficient after correction is
100 kN ÷ 1993 × 10-6 = 0.05017 kN / × 10-6.