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.

where the use of direct action control valve?

2 Answers  

---

defination of plc? why we use plc? application of plc? advantage of plc?

4 Answers  

---

why ultra sonic level transmitter is installed in 90 degree?

2 Answers   ME,

---

What are the charecterstics of control valve.

2 Answers  

---

hi... i'm about to learn siemens plc i came across following question in my mind ... plr ans 1. hw motor operated by plc 2. hw drive operated by plc explain dis by both ladder logic diagram and hardware config , connection

2 Answers   KCP Cements,

---

i want use pressure transmitter for flow ,how?

5 Answers   Gasco,

---

what is the difference between 3,4 wire RTD sensor?

6 Answers   HTA Instrumentation,

---

Which softwere is required to communicate the S7-300 processor

4 Answers  

---

pl give the guidance for DUBAL written test

1 Answers  

---

what is the basic principal of vertax flow meter

3 Answers   Balrampur Chini Mill, Saba,

---

one rtd sensor which is connected at middle of distillation column where actual temp. is 100deg but when we tight this sensor at thermowell end it goes down to 90 deg & when remove from the thermowell(but sensor end dipped in well) showing actual reading, what is reason?

3 Answers  

---

What is governor of turbine?

3 Answers   Reliance,

---