Answer / carl_ellis

The fail-safe feature in temperature measurement uses some means to detect an open circuit in the sensor input wiring. An open circuit could be a broken wire, loose connection or a failed sensor.

Should an open circuit be detected, the output signal representing temperature will drive either full scale up usually to a value higher than 20.0mA or full scale down to a value lower than 4.0mA in order to flag, alarm or indicate a failed input circuit.

The failsafe feature and setup for upscale or downscale under fault conditions is sometimes referred to as "thermocouple break". In heating applications, upscale break is usually chosen because an indicated very high temperature on a controller's input will drive a controller's output down to 0% output (assuming reverse control action), preventing an overheat, fire or potential damage situation.

Some failures, such as a shorted thermocouple extension wire or sensor drift can not be detected in with open circuit detection.

Carl Ellis
Measure First

what is pt100 RTD, and does 100 stands for

8 Answers   Tata Power,

---

In Boiler Drum Level- Level control valve how can it tuning (PID)?

2 Answers  

---

Whether the DI, DOs shields can be connected with Analog Input Shield Earthpit?

0 Answers  

---

what is basic working principle of Governer in power plant?

3 Answers  

---

How to measure the vibration..?

1 Answers   Madhucon,

---

what is meant by nuclear collector?

0 Answers  

---

what is puling in n pulling out in flame scanner system?

1 Answers  

---

why we use 3 wire rtd direct wiring for temperature measurement instead of temperature transmitter like bearing temperature

0 Answers   ABG Energy,

---

Identification of control valve parts.

0 Answers   CCIE, Oil and Gas Jobs,

---

Can I calibrate the Electromagnetic Flow Meter on line and How.

0 Answers   SEWA,

---

how to calculate density?

2 Answers  

---

I was working on calibrating turbidity transmitters endress+hauser at effluent polishing plant.We calibrated using NTU buffers.What happened is that when we immersed the sensor, everytime we raise and lower the sensor gradually, the reading will vary.my question is that is there any specifications on what is the required distance from the bottom of the container with buffer to the face of the sensor?Is it ok to install the sensor in a medium which has turbulence specially if bubbles are present?

0 Answers  

---