Excitation method and excitation voltage of hand-held vibrating wire vh501tc acquisition instrument

The acquisition instrument excites the vibrating wire sensor ： Also known as “ Excitation ”, It is a necessary process for the frequency data acquisition of vibrating wire sensors , Only when the sensor receives Natural vibration can be generated only after appropriate excitation signal , Only when the vibrating wire sensor produces natural vibration can the frequency signal be output , further , The reading circuit will detect and read the natural vibration signal of the vibrating wire sensor , Can be calculated Vibration frequency value . Excitation signal of vibrating wire sensor （ The external signal that can make the sensor produce natural vibration ） The general points There are two types , One is high voltage short pulse , A class of multiple groups of continuous low-voltage pulse signals with specific frequency .

High voltage pulse excitation ： Use higher voltage （100~200V） Send a short pulse to the coil of the vibrating wire sensor , The process or method of making the vibrating wire sensor of any frequency produce self vibration .

Low voltage sweep excitation ： The use is equivalent to the natural vibration frequency of the sensor （ near ） The frequency of sends a continuous signal to the vibrating wire sensor Low voltage of the （3~10V） Pulse signal , The process or method of making the sensor vibrate naturally .

VH501TC Provide a variety of vibrating wire sensor excitation methods , To maximize compatibility with more models of vibrating wire sensors . The excitation method parameters of the vibrating wire sensor are located on the right side of the real-time data window , share 5 Two methods are optional , Use them separately MODTH0~MODTH4 Express . Various methods are described below ：

The excitation voltage data is displayed on the screen as xxx/xxx In the form of , The front number represents the actual excitation voltage , The following numbers represent the excitation voltage source voltage VSEN. The power supply used for high-voltage pulse excitation and low-voltage sweep frequency excitation methods comes from VSEN, relatively speaking , Use higher VSEN Can get better sensor signal , But some sensors must use lower VSEN Voltage will get stable frequency data .VH501TC There are two versions , When it is necessary to modify the excitation method or excitation voltage source , If there are two rotary switches on the back of the device , Then turn the switch directly ; If there is no rotary switch, you need to use the above operation keys to modify the parameters . The meaning of the gear of the rotary switch of the excitation method is the same as that in the above table , Drive the gear of the voltage rotary switch 0~15 Presentation settings VSEN by 0~15V（ front 5 The gear is fixed to 5V）.

Be careful ： Suggest VSEN The voltage of should not exceed 12V, Recommended setting as 5~8V. If VSEN The voltage setting is too high , Measure some small resistance values （ Less than 200 ohm ） There is a risk of damage to the sensor or equipment . In use , Pay attention to observe the vibrating wire signal quality value displayed on the screen , For a certain class or some sensors , Different excitation methods will have a great impact on the signal quality , The switching and use of excitation methods should take the highest signal quality as the selection standard .