Calibration of vibration measurement and analysis systems, like other instrumentation equipment, is one of the important requirements in manufacturing plants. 1. In factories, vibration measurement is usually done with the two objectives of protection and condition monitoring. 2. In protection systems, the machine continues to operate. It depends on the measured vibration being below the permissible limit, so the inaccuracy of the vibration measurement can unnecessarily stop the production or, on the other hand, cause fatal damages. 3. In condition monitoring systems, with a lower degree of importance, the non-calibration of the measurement system causes wrong judgments regarding the condition of the machine and incorrect diagnoses, and 4. as a result, huge costs are imposed on the factory.

Tavator Sepahan Engineering Company provides calibration services for all types of non-contact and contact sensors, as well as vibrometers and analyzers, using various calibrator, shaker, controller, oscilloscope, analyzer, etc. equipment. These tests include the following:

Laboratory calibration:

Calibration of body sensors (accelerometer and speedometer)
Calibration of proxy sensors: static behavior test and dynamic behavior test
On-site calibration

Calibration of body sensors

Calibration of body sensors including accelerometers and speedometers is done by shaker and vibration controller. In this test, the frequency response of the sensor is measured for the frequency range of the desired function. Usually, these types of sensors do not have the possibility to change the sensitivity and cannot be calibrated for the defined sensitivity, but their sensitivity can be measured at different frequencies. The result of the test is whether the sensor is acceptable or not. And of course, the sensitivity of the sensor is measured and displayed at different frequencies.

Test methods

The best way to measure the sensitivity of these sensors is to install them back to back with a special calibration sensor and use a separate controller, shaker, and analyzer. In the absence of a special calibration sensor, an alternative reliable sensor and vibrometer can be used.

In another method, the reference vibration measurement is done by the calibration shaker itself, and the output should be measured with a monitor or voltmeter. This method can be done on the site and does not require any additional equipment.

Usually, these calibrators have the ability to connect to a computer and can provide confirmation of calibration results automatically

Calibration of non-contact sensors – proxy

Since the proxy sensors have both DC and AC output together, the calibration of the proxy sensors includes two static and dynamic test parts. Installation of these types of sensors should be done with higher accuracy than contact sensors.
1 In the static test, the DC output of the sensor is recorded by a voltmeter for different distances of the sensor head from the target (substitute shaft) and the sensitivity diagram of the sensor is drawn and calculated according to these values. 2. In this diagram, the non-linear area below and above the sensor is also defined.
3. In the dynamic test, the AC output of the sensor is measured by a vibrometer for the sinusoidal movement of the target plate (instead of the shaft) with a predetermined range and compared with the original value.
The calibrator of this type of sensors is known as the TK3 device.

On-site calibration – loop check

In the warm check loop, the sensor vibration measurement systems are opened from the installation site and closed on the shaker (for body sensors) or on TK3 (for proxies). By creating a vibration with a certain frequency and amplitude, the desired value should be read on the monitor of the control room and compared with the value of the shaker. Usually up to 2% of the line is acceptable.