What is turndown ratio?
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Forget about this concept. This post was last edited by marry on 2009-4-2 09:29 ]
It is the ratio of the maximum allowable measuring range of the instrument to the minimum allowable measuring range.
Range ratio refers to the ratio of the maximum value to the minimum value that the instrument can measure while meeting the accuracy requirements.
When the usage requirements are met, the ratio of the maximum range to the minimum range is currently more than 300 for most transmitters.
It’s basically explained clearly above
The larger the range ratio, the better. If the range ratio is too large, the accuracy marked on the transmitter will not be reached at the extreme range.
It is the ratio of the maximum allowable measurement range of the instrument to the minimum allowable measurement range. This is very important!
Turndown: The ratio of the maximum allowable measuring range of the instrument to the minimum allowable measuring range. However, those who engage in instrumentation must not be fooled by the manufacturer's advertisements and manuals. If the maximum range or minimum range is used, it is recommended that you replace the instrument.
The answer can be found in the control instrumentation book. For example, the measuring range of a flow meter is 25~250m3/h, then the range ratio of the flow meter is 10: 1.
personal understanding: The range ratio is the ratio of the lower measurement limit to the upper measurement limit of an instrument. For example, the measurement range of a flow meter is 5m3/h ~ 50m3/h, then its range ratio is 1: 10.
The ratio of the maximum adjustable range of the instrument to the minimum adjustable range
Instrument range ratio For various flow meters, the measurement ratio is different. Some are large and some are small, depending on the principle on which the flow meter is made.
Generally, the measurement range labels are 0-a certain value! How to find the ratio? !
Besides temperature, how many can measure 0?
Turndown ratio is actually the ratio of the maximum flow rate to the minimum flow rate.: Range 5: 1. When the minimum flow is 20m3/h, its maximum flow is 100m3/h
If the factory range of the transmission is 100kp, but if you choose a larger range, you may actually only use 20kp. If the range ratio of this transmission is large enough, it is greater than 100: 20 means the range ratio = 5, then this transmission can be used. A large range ratio means a large transmission adjustment range, which can reduce inventory backlog. However, if the range ratio is too large, the error will increase when the range used is too small than the maximum range.