Answer / carl_ellis

Question:
Controller not working in auto mode?...what are the problem can occur...Pls explain

Answer:
If a controller is not in automatic mode it is either broken or in manual mode.

In manual mode the controller's output is fixed at some percentage output and the controller is not adjusting its output to maintain the setpoint (SP).

While running at a fixed output, the process's process variable (PV) will generally stabilize at some value above or below the setpoint. PV changes will be dependent on external influences, like load changes.

However, if the output reaches an extreme, like 100% or 0%, the process can be put in jeopardy of going into a hazardous state from the uncontrolled input into the process or removal from the process of energy or mass, whatever the controller is controlling. Presumably, safeties are in place to shutdown the process should those dangerous conditions result from manual mode.

Carl Ellis
Measure First

How to define the size of control valve?

5 Answers  

---

What are the two states of a controller

3 Answers  

---

principle of rtd

4 Answers  

---

Calibration of controller (pneumatic)

0 Answers   CCIE,

---

why we should maintain neutral earth voltage below 1V while calibration? why cant it be 1.2V or 2V

0 Answers   Hospira,

---

hello i'am samad.Any one Can help me! How to calibrate Vaccum Transmitter DP Type range 0 - 50 mbar abs by hand pump calibrator.

4 Answers   Bharathi Cement,

---

please send the drdo exam paper

0 Answers   DRDO,

---

We are used CENTUM CS3000 of YOKOGAWA. please tell me how to simulate wihtout FCS and vnet.

1 Answers  

---

What is instrumentation instrumentation engineering?

0 Answers  

---

What is surge and how is it prevented.

1 Answers   ADMA OPCO,

---

Which products are available in the Mass Systemswitch and System Manager AC range?

0 Answers  

---

what is the difference between 2 wire and 3 wire RTD- application wise,cost effectivity?

2 Answers  

---