WHY WE NOT USE 2-20mA,1-20mA,3-20mA or 10-50mA SIGNAL?
INSTEAD OF 4-20mA.
Answers were Sorted based on User's Feedback
Answer / ali abideen ,,
Generally in a transistor some amount of voltage is
required for turning it on. This voltage is the cut in
voltage. Up to this voltage the exists a nonlinearity in
its characteristics. Beyond this cut in voltage the char.
of transistor is linear. This nonlinear region lays between
0-4ma, beyond 4ma it linear. This is why 4-20 ma range is
used.
Is This Answer Correct ? | 29 Yes | 13 No |
Answer / anil
starting with 4ma is to know DEAD or LIVE of the
transmitter,4 to 20 is used for linearty and according to
ohms law to covert 1 to 5 volt dc,
Is This Answer Correct ? | 19 Yes | 4 No |
Answer / lalatendu keshari prusty
4-20ma signals will travel along distance without dropping signal value and the internal circuit distinguish between connection break & minimum value.
Is This Answer Correct ? | 0 Yes | 1 No |
Answer / mike betts
I am not sure why the range of 16mA i.e 20 - 4, but the 4mA
starting is so that you have a posative value of current for
all values that the loop current represents. This way, if
you have no current at all, the loop is open circuit for
some reason.
Is This Answer Correct ? | 4 Yes | 9 No |
Answer / vanapalli rajesh
because 4-20ma is a linear range compared to other ranges
Is This Answer Correct ? | 8 Yes | 22 No |
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