Two Wire And Four Wire System

In what context? C'mon give us more detail, else some smart ar$e will just reply by saying.

"2 wires"

Are you talking about power supplies with sense wires or communication protocols or what?

Del

May I suggest the following book,

"Instrumentation for Engineers and Scientist", by John Turner and Martyn Hill

Oxford Science Publications, ISBN Number: 0-19-856517-8.

This is one of the better begining instrumentation books and a good reference though a little dated.

Also, next time you post a question, please provide more information

Hope you get your question answered.

I'll put on my Carnak turban here:

2_3_and_4_wire_RTD's If that's it, I'll elaborate.

I've traveled the long, long way down from my Ivory Tower to do this. And I'm sure Ill be chastised for my interjection of a little levity with the Carnac wise-crack.

_{(But I don't care because it's a long, long way back up, and by the time I'm there I won't care because I nip along the way.)}

In two wire system pt100 sensor between 2 wires.and aslo effect teh cable resistance in measurement.

In 4 wire system pt100 sensor between 4 wires .two wires are parallel each other.u know resistance decrease if connect in parallel.so cable resistance effect less on measurement.

Hi

The major difference between 2 and 4 wire systems is that for 2 wire systems power and signal are carried on the same set of wires. Also known as loop powered devices.

For 4 wire systems a separate set of wires supplies device power and a separate set is used for signal.

The advantage of 2 wire systems is half the wire runs are required. The disadvantage is relatively low impedance capability that may limit the type and number of devices you can drive with the signal as well as distance that the signal can be transmitted before circuit loading occurs.

The advantage of 4 wire systems is higher signal side impedance, so better loading and signal transmission distance characteristics. The disadvantage, more wire.

Regards

Jose John