Answer / suresh

why put 4-20ma na process zero or live zero.

Answer / pradip

*To determine live zero
*To avoid noise
*Linearity is maximum
*Transmission of signal over long distace

Answer / kambiz

why 4ma show higher zero ?
i have transmiter flow renge 0-1000 m3/h but 4 ma show in
monitoring 200 m3/h and 20 ma show 1000 m3/h i want when 4ma
show 0 m3/h and 20ma 1000m3/h

Answer / smruti senapati

with 0-20 ma you canot distinguish between minimum field
value and connection break.with 2-20 ma ,internal circuits
can distunguish between connection break of minimum
value.normally when the value is minimum the transmitter
will give you 4 ma while in case of connection breakage it
will give 0 ma...

Answer / rajesh

As per Numerology 4 is the good number for all analog instruments. next number of 4 is 5. multiply both of them
(4 x 5 = 20).

So only 4 to 20 MA is used in all Analog Signals.

Note: Sorry Friends, i just check whether this website accept all answers or filter.

Don't accept these answers even more no of YES. Because everyone will answer this website without knowing the answer.

Answer / palak m

Why only 4 mA, why not 1,2,3 mA? Because it is universally
tested and approved that at 4 mA the signal has minimal
interference.

Answer / bill

4 milliamp is used as span lower limit, because some
elements on the loop require power from the loop and
therefore a minimum level of power must be available

Answer / imran

The minimum value is 4 mA is because to avoid any confusion
of out put at lowest value.

Answer / saravana

one of reason may be the threshold value

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