Answer / mariyappan

Because of dead zero and live zero concept.
Dead Zero: this is basically derived from ohm's law
V=IxR. In electronics circuit minimum 250 ohm resistance is using. so V=Ix 250. Substitute I=0,1,2,3,4 after substitute 0 u will get V=0 ohm,(1;V=250 ohm,2;V=500 ohm,3;V=750 ohm,4;4=1000 ohm or 1 V) so when 4 ma is coming u will get 1 V,8 ma=2v,12 ma=3 V,16 ma=4v,etc..... u will get linearity .thats why 4 ma is choosing in all analogue value.
Live Zero: if tx is failure that time also zero value is coming.thats why 0 is not choosing

Linear amplifier.

0 Answers   CCIE,

---

what is Analog input/output & Digital input/output,

2 Answers   Bapco Bahrain Petroleum Company,

---

what is function of PLC, and how is it work , explain with difination

1 Answers   Bapco Bahrain Petroleum Company,

---

What is Square Root Extractor for?

9 Answers   Sabic,

---

Why we used cage in control valve?

8 Answers  

---

How can we calibrate the level interface for Fisher® FIELDVUE® DLC3000?if use water to calibrate and our liquid SG are 0.75 and 1 ,Displacer height=14" and How much should be set SG in trasmitter during calibrate,for URV and LRV how shold be set

1 Answers  

---

why we are using boosters at glass furnace is there any other thing?

1 Answers   CGL,

---

What are the different type of instrument used in cement industry with uses

2 Answers   Lafarge,

---

What are the different modes of a contollogix family processor? How they work?

3 Answers   Honeywell, Siemens,

---

why we use by pas on a positioner? When can a by pass be not used on a positioner ?

1 Answers  

---

what is bms?

4 Answers   Emco,

---

how to draw a flowchart for swapping two numbers using bit wise operators?

1 Answers  

---