Why any transmitter signal is 4-20 mA only Why is started from lower range 4 mA

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Why any transmitter signal is 4-20 mA only
Why is started from lower range 4 mA and upper range is
20mA.

Question Posted / vpp788

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Why any transmitter signal is 4-20 mA only Why is started from lower range 4 mA and upper range is ..

Answer / anshul jaiswal

if we use 0-20 mA scale for 0-100%,then 0% will be read in two cases;1)when instrument has any kind of damage problem(not responding case)& 2)for the ground level reading.so we use 4-20mA which shows 4mA for 0%(ground level) & 20mA for 100%(full value) and 0mA shows that instrument has any damage problem.And guyz,in the range of 4-20mA the calibration shows linear characterstic too.

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Why any transmitter signal is 4-20 mA only Why is started from lower range 4 mA and upper range is ..

Answer / ramali

current output is 4-20 mA.
Let take a transmitter operating range is 0-100%
in this case, 0% is only 4 mA,100%is 20 mA.
Because the transmitter have no power,then its output is
0mA.That means zero , live zero.
zero means there is no process is done.
live zero is transmitter have no power,etc.,

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5 Yes

0 No

Why any transmitter signal is 4-20 mA only Why is started from lower range 4 mA and upper range is ..

Answer / p.v.srikumar

because if use 0 -20 mA as 0-100% there is any signal cable
damage or cable open it will show only 0%. if use 4-20mA as
0-100% it will show bad process value(live zero).

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13 Yes

9 No

Why any transmitter signal is 4-20 mA only Why is started from lower range 4 mA and upper range is ..

Answer / yakin patel

Upper all answer is right but its 4ma not 3,2,1 bcz it is calculting prove. Has calcultion

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Why any transmitter signal is 4-20 mA only Why is started from lower range 4 mA and upper range is ..

Answer / girish

this answer which are not exact answer
1. signal is linear
2.no noise
3.current signal will not drop

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3 No

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