Vibration & temperature
Wilcoxon Research designs a number of sensors which provide more than one output. Wilcoxon has some sensors that provide both a vibration signal and a temperature signal.
These dual output sensors are useful for those situations where users wish to know the temperature of the machine where the vibration is measured. One example is in paper machines where users want to know the temperature at the mounting locations in the dryer section.
The vibration portion of the sensor is powered in the same fashion as all other industrial vibration sensors. Voltage is supplied to the sensor through a constant-current diode and the sensor maintains a characteristic Bias Output Voltage (BOV). The sensor superimposes the vibration upon the BOV where it is available for the user.
The temperature sensor operates in a similar manner in that it must be powered through a constant-current diode and the DC bias voltage relates to the temperature. The temperature measurement is done using a special integrated circuit “chip” that produces a DC output voltage signal. The signal changes by 10 millivolts per degree Kelvin. Since a one degree Kelvin change is the same as a one degree Celsius change, the only difference between them is in the reference temperature, where 0ºCelsius is 273º Kelvin.
As an example, at a temperature of 300ºK (27ºC) the DC temperature signal would be 3.00 Volts DC.
|Model||Sensitivity||Sensitivity tolerance +/-||Frequency response @ +/- 3db||Max temp.||Accel Range||Haz area option|
|Dual output vibration (4-20 mA) and temperature sensors|
|PC425 low profile||4-20 mA||5%||4 - 2k||85°||5,10,20 g|
|PC427 integral cable, low profile||4-20 mA||5%||4 - 2k||85°||5,10,20 g|
|Dual output vibration and temperature sensors|
|786T||100 mV/g||5%||0.5 - 12k||120°||60||Y|
|787T||100 mV/g||5%||0.5 - 12k||120°||80|