What is the damping of a gauge
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Damping is often set, and today I was asked about a problem related to turbine flowmeters. For example, if the damping is set to 0, then there is no damping, and the pulses resulting from the real-time display frequency are as they are. For example, if the damping time is set to 5 seconds, starting from 0, then during the 0-5 second period, the value displayed should be 0. At the 6th second, the average of the data from the first 5 seconds is calculated; let’s say this average is A, and then A will be displayed throughout the 6-10 second period. When the 11th second arrives, the average of the data from 6-10 seconds is calculated again, and this value, B, is then displayed, with B remaining visible during the 11-15 second period. If at this point, at the 100th second, the turbine suddenly gets stuck and the flow rate drops to 0 instantly, then there is still a flow rate reading between seconds 100 and 105; it is only starting from second 105 that the flow rate truly drops to 0. Something seems wrong here, because in many flow meters, the reading goes to zero right away, without any such trailing effect. And when it starts up, the traffic is displayed directly as well
Damping is neither a moving average nor filtering. Damping is essentially achieved by connecting a lagging element in series; it is usually a first-order lag, though second-order lags are also used, but less frequently.
Personally, I think it refers to the value at the next instant after the set value is determined; for example, if the damping time is set to 5 seconds, then the instantaneous value is output every 5 seconds.
Could we go a bit deeper? I did some research, but I still don’t understand it clearly
Assuming that the parameter being measured experiences a sudden change (step change), the instrument reading (signal) can exhibit several behaviors: 1. The instrument reading (signal) also undergoes a sudden change (step change); in this case, there is no damping； 2. A first-order rise curve may occur (that is, at the moment when the parameter under measurement changes suddenly, the instrument reading or signal starts to change and then gradually approaches a stable value); this is also known as aperiodic variation. The speed of this change is determined by the damping time (damping coefficient), and a slow rise indicates an excessive damping time ； 3. An attenuating oscillation curve (with varying attenuation periods) may occur; if the attenuation is slow, it indicates that the damping time is too short ； It is almost impossible for the instrument indication (signal) to change immediately when the parameter being measured does so, as there are resistances and energy-storing components within the instrument. If there are multiple resistance and energy storage components, a higher-order system is formed, which leads to oscillations. Excessive damping results in a prolonged stabilization process for the signal, but no overshoot occurs. If the damping is too low, oscillations occur, overshoot takes place, and the stabilization time is also long. With appropriate damping, it should stabilize after oscillating once or twice.
Thank you, I’ll study it further. For example, in my turbine flowmeter, as everyone knows, pulses are used; the frequency within 1 second is measured and then converted into flow rate. So how should I design the damping in this case?
Could you help me design a formula for instrument damping?
Could you help me design a formula for instrument damping?
In simple terms, it refers to the response speed of the instrument; it has no impact on the accuracy of measurements
It has some effect; I have a gauge with a good damping design, and I don’t know how it was designed – I always thought it was based on a simple average
It’s equivalent to a frequency measurement correction