Answer / vishal

In case of drum, it contains both water and steam and the
zero is located the midway to maintain optimum level in
drum say -30mm is maintained for safe boiler operation and
high levels are controlled to avoid water rushing to super
heaters and damaging turbine and simmilarily very low drum
levels are avoide to protect overheating of drum and
prevent excessive rise in drum metal temperatures. but in
case of deaerator we are only concerned with the actual
level present in it to indicate in control room.level
ranges are generally in accordance with the height and we
take 0 for min level and for eg 1000mm if the height is
1200 mm or equivalent for safe operations .

Answer / tarique

to maintain your sp as per load control,for anti cavitation
in your system it will always monitor true value

in any transimitter (flow/level) there are three terminals for supply& test (+,-,+)in two wire,24VDC given to Tx.,but how 4-20 ma signal travels thru same wire (as it is for 24VDC input supply)?

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What is the working principal of Mass flow transmitter?

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