센서(transducer)를 선택함에 있어 중요한 순위를 따진다면 단연 감도(sensitivity)와 'Frequency range'일 것이다.
진폭과 주파수의 그래프에서 세로축을 설명하자면, 하나의 센서가 모든 진폭을 측정할 수 있다면 좋겠지만 감도에 따라 다르기 때문에 절대로 그렇게 할 수 가 없다. 이와같이 가로축을 설명하자면 모든 센서가 모든 주파수를 측정할 수 있다면 센서를 선택해야 할 이유도 없다. 이런 이유로는 진동센서 종류별, 더 세분화해서 각 진동 센서(가속도센서도 포함) 종류별로 고유하게 측정이 정확한 구역의 주파수 구간이 각기 있기 때문이다. 이 것을 Frequency range라고 한다.
When you want to measure vibration, you need to think in
advance what unit you need to calculate it. This is in line with what needs to
be tailored to the unit to be evaluated and what kind of sensor to select.
Therefore, when expressing the amplitude of vibration as a unit, you need to
know more rules than you think so that you can communicate knowledge with each
other.
That is, different amplitude units are used depending on the object
to be measured (building, person, machine), main frequency (low frequency, high
frequency), or target of interest in the result (stress, energy, power). can
never be unified. This is because different units are used in written standards
for evaluation, reference standards, measurement standards, specifications,
regulations, and laws.
Choose between displacement, velocity,
and acceleration
Displacement, velocity, and acceleration can be
converted to ..................................
The results of the vibration diagnosis can be confirmed
as a technical report, which is largely divided into a simple diagnosis report
and a detailed diagnosis report, etc., and is prepared including the cause and
evaluation of the current vibration problem, and a description of
countermeasures if necessary. The meaning of each report is a simple report in the case of
simple evaluation of phenomena and absolute standards after temporary
measurement, and detailed analysis to the extent that current causes can be
analyzed and countermeasures can be found through spectrum analysis and cause
analysis of various vibrations. are treated as detailed reports. In general, the
definition of regular textbooks for facility diagnosis qualifications is not
very different.
Simple diagnosis and precise diagnosis,
offline and online
First of all, if you look at the methods of simple
diagnosis, there are 'route measurement' and 'online monitoring system'. Inspection is commonly
referred to as 'off-line' as a method in which humans intermittently
investigate and record the state of equipment using a portable instrument
(vibration meter, data collector). On the other hand, constant monitoring is a method of
continuously monitoring by a monitoring device and is called 'on-line'. Inspection called
off-line can measure many measurement points and directions, but it cannot be
said to be continuous depending on the frequency of measurement. There are
advantages and disadvantages between the two systems, since on-line
continuously monitors and stores near real-time data from already installed
sensors.
