Answer / naveen

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

what is use single seated and double seated valve?

2 Answers   Doha Petroleum Construction DOPET,

---

What are the materials available to prepare individually for competetive exams in Instrumentation field? Plz reply...

0 Answers  

---

What is Electrical Runout & Mechanical Runout in Vibration measurement.

1 Answers  

---

What are the key components of control loop?

1 Answers  

---

what is output of FOUNDATION FIELD BUS transmitter

0 Answers  

---

why micro controller 8051/52's clock frequency is internally divide by 12 ?? and why it is further divide by 32 in UART serial communication ??

1 Answers  

---

what is gas metering system? gas chromatograph? and gas compressors?

0 Answers   HPCL,

---

please suggest me, how can i change the display setting in term of unit in place of % of Honeywell pressure transmitter ST3000S100?

2 Answers  

---

What is the standard height for stancion supports? and what is the standard mounting height for different transmitters?

11 Answers   Samsung,

---

What is the Main principle and formula for the steam flow compensation?

2 Answers  

---

How can we cheak the ENCODER ?

1 Answers  

---

WHAT IS INSTRUMENTATION?

17 Answers   ITC Infotech,

---