Answer / faiyaz ahmad

As we all know, each and every thing has some resistance.Like wise,the resistance of the conductor increases with the length of the conductor.
2 wire- The RTD element's resistance will be calculated between 2 wires.i.e; positive & negative.In this measurement, the RTD output also includes the resistance of the 2 wires which we use to connect from RTD element to temperature transmitter.
3 wire- The RTD element's resistance will be calculated between one positive and two negative terminals.In this measurement, the RTD element's third wire is used to compensate the lead resistance of one neagative wire as both the wires get shorted and resistance of the two negative wires is approxiamately 0 ohms.But still the resistance of the positive wire will get added in the output which is almost negligible.
4 wire- This 4 wire measurement is used where we need almost
100% accuracy.The RTD element's resistance will be calculated between two positive and two negative wires.In this measurement,two positive wires will get shorted and two
negative wires will get shorted making the lead resistance of both the wires eliminated approxiamately.

Answer / raj7.eie

I dont think there is a thing called 3-wire.
2Wire means it has one supply line and one signal line.
4Wire has 2 supply line and 2 signal line.

how to calculate temp.prapotional to mv in thermocoulpe.

2 Answers   Electronics, KNPC,

---

difference b/w single acting and double acting actuator by using application only?

2 Answers   McDermott,

---

What is the reason for not giving very High Proportional Gain Kp in PID Controller?

2 Answers   ABB,

---

Convert a pressure, level, flow, or temperature process variable value into the appropriate pneumatic or electrical value given different types of instruments.

6 Answers   Jindal, MCL, Thermax,

---

Example of dry contacts & wet contacts?

3 Answers  

---

What is full form of hart communicator?

2 Answers   KOC, UPL,

---

I need to know steps to Calibration Valve Guard......

0 Answers  

---

what is the protection system in solar turbine compressor

0 Answers  

---

If we increase PI controller what will be action.

1 Answers   IMECO,

---

why can't we use 5-20mA standard or some other instead of 4- 20mA?

6 Answers   Emerson,

---

What is difference between ESD and PLC please Explain me clearly.

0 Answers  

---

Actual using of tube bender to bend 2 opposite 90 deg at correct measurement center to center of tubing.

0 Answers   CCIE,

---