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

what is the difference between Ethernet unmanaged and managed Switch?

2 Answers  

---

What is fault tolerent system

2 Answers   GNFC,

---

pressure switch range 0 to 2bar.i have to install from ground level to 5 meters height.what is the formula the to increse the range ? and every 1 meter how much pressure should be add ?

3 Answers  

---

How can i test procedure grounding for CAT-7 cable? Or How can we test procedure CAT-7 Cable Electrically safe?

0 Answers   Tecnimont,

---

What is the difference between DCS and SCADA?

1 Answers  

---

There are many type of control cable like pair,core,tried, What are defination each one

0 Answers   Birla,

---

what is metal of piston ring

0 Answers   MahaGenco,

---

how level can be measured in open tank with reference to pressure

1 Answers   Atul, INOX,

---

define COMPENSATION??

4 Answers   Bosch,

---

what is mean by loop checking?

8 Answers  

---

In a class of 150 students, 40 passed in Social Studies, 90 passed in Science and 30 failed in both the subjects. vi)How many students passed in at most one subject among Science and Social Science?

7 Answers   CAT, CGI, Cipla, KHK, Visa,

---

Any Transmitter Range (Span value) start from 2?

1 Answers   Exxon Mobil,

---