Answer / carl_ellis

There's two kinds of feedback from a control valve:
a) the change of the process variable because the valve
position changes
b) position feedback directly from the positioner to the
controller/control system.

We'll assume that the question is directed at the loss of
position feedback signal from the loop's positioner.

1) Position feedback cards are options on smart
transmitters and need to be initialized after installation.
Has it been initialized?

2) DC power is typically loop power for position feedback.
Is the loop power supply still functioning?

3) Has the position feedback card or its wiring been
disabled or removed?

4) If the position feedback loop is intrinsically safe, is
the loop's I/S barrier open circuited?

5) Has the loop wiring been changed in some manner so as to
affect the position feedback signal integrity?

Carl Ellis
Measure First

I need the intools training institute address in india. Intools subject oriented local authors books.Refer me plz

3 Answers  

---

I am a instrument technician. recently i attend interview and face one of question for DP transmitter ,the client asking about the calibration of DP transmitter ,am answer the calibration procedure, they will ask one more question. why open LP side in atmosphere? i did not answer that question. so please help me and explain the particular question. Dear firends waiting for your valuable replay

3 Answers   Qatar Petroleums, Samsung,

---

what is the difference between profibus and controlnet networking.

0 Answers   HZL,

---

Basic working principle of control valves

1 Answers  

---

what is the control valve?how many types of control valves are there

6 Answers   Chemin, Hindustan Zinc,

---

what is the procedure of O2 analyser calibration?

3 Answers   Thermax,

---

WHAT IS THIS INSTRUMENTATION?

7 Answers  

---

What is the exact output of eddy current proximity probe? For vibration mesurment?

2 Answers  

---

WE ARE HAVING YOKOGAWA CENTUM CS 3000 DCS, 2 FCS AND 4 HIS " When the operation Download to HIS message appears: Equalize start. HIS0163 WARNING: Could not connect to equalize destination. (7001) Retrying. Number of retries = 0/1 ERROR: LdXopsLoadMain: connect error 10060 ERROR: LdXopsLoadMain: connect error 10060 ERROR: Processing terminated due to connection error. (7002) Equalization end with errors. HIS0163 ---- ERROR = 3 WARNING = 1 ---- Tell me, please, why and how to solve the problem."

6 Answers   Khas Pvt Ltd, Yokogawa,

---

Is it possible to drill additional gland hole in EExd or EExe JBs? What are the points to take care?

2 Answers  

---

tell me the temp range of rtd?

8 Answers  

---

what is o2 analyzer and how it measured ,what is the role of this analyzer in cfbc boiler...

0 Answers   Mittal Steel,

---