Answer / kandan

since we use 4 to 20ma transmission signal,the voltage drop
at the o/p is 1 to 5V.

In the O/P 250 ohm resistance is used.So when the signal is
4ma then 4*250=1V

when the signal is 20ma,then the O/P is 20*250=5V.

Answer / ranjit mallick

Because upto 1 volt and 4ma the signal can be trigered due
to some earth leakage, bias malfunction, noise signal,
small magnetic interferance etc.Hence it is used as lower
tolerance to avoid unwanted triggering of the instrument
and can be termed as floating output.

Answer / abdul hakkem

for analog arithmetic calculation can be done only by Voltage, thats way 4-20 mA is converted & taken as a voltage output

Answer / rajesh

Because of the Burden resistance of the Instruments/Load of

PLC are normally 250ohms

So Its Corresponding we will get 1 to 5V

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