Answer / senthil

1.During commissioning, we ll do loop checks.it means from
field instrument( PT,TT,FT,LT or switches) the signal is
checked with the DCS.
for example : consider a PT,we ll simulate 4 to 20 mA in the
instrument and the same value should be shown in the DCS also.

2.there are two loops
open loop and closed loop
closed loop for controllers to control the process.for
example, antisurge control in Gas Compressor,Three element
control in Boiler

Answer / g.venkat

There are two loops
1. open loop
2.close loop


open loop using for monitoring and recording purpose

close loop using for controlling the fianal control element

Explain the key components of control loop?

0 Answers  

---

What is the PLC configuration in Cement industry?

0 Answers   IMCO, Maha Cement,

---

Area classification, Equipments, Gas groups, temperature classification, Ingress protection, Fire Extinguishers.

0 Answers   CCIE,

---

what is the working principal of pribe

0 Answers  

---

I have applied the post Junior Engineer-(TM)in R.R.B CHANDIGARH recently . what type of question i have to practice and which book ?. can i get any model question paper?

3 Answers   RRB,

---

what is zero trim and span trim?. at which problem we need to use this?

3 Answers  

---

If a differential pressure transmitter is calibrated for 0~2500 mmH2o and transmits a 4~20mA dc signal. The transmitter is placed across an orifice plate which is sized to create 2500 mmH2o differential at 5000m3/Hr a) what is the flow rate when the transmitter signal is 13.0mA DC? b) what is the signal output of the transmitter when flow rate is 2500 m3/Hr ?

5 Answers  

---

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

1 Answers  

---

What skill/s does the Instrument Technician has?

6 Answers  

---

What is stripper & spilitter ? Diffrence in this.?

0 Answers  

---

which flow meter is use for measuring the open channel flow?

2 Answers  

---

How can we say that accuracy of measurement increases by using 3 or 4 wire RTD? because for example: If resistance of RTD element is say r ohms and Resistance of the cable from transmitter to RTD is R ohms And if 4 wire RTD is used, ____._____________________ R ohms | |_____._____________________ R ohms / \ / r ohms \ \ | |______.__________________ R Ohms | |_______._________________ R ohms Then the actual resistance measured will be: Total = r + R/2 + R/2 = r +R Ohms Note: r+R instead of r ohms. hence error

2 Answers  

---