Answer / lokesh gatty

We cannot control through thermocouple/RTD, they are only
measuring elements,which is connected to temperature
controller which as set value for which point it has to
control temperature (PID/Relay logic control)..Meanwhile
Temperature transemeter is used to convert mv/ohm to anolog
signal(4--20 ma)...we have to refer ohms/mv to degree Celsius
table

Answer / aditya kaushik

When we are using the rtd/thermocouple, The output is in mv
or Ohm variation wrt temperature, that will nt be directlyy
processed by our dcs/PLC so we are using transmitters to
convert it to 4-20 ma accordingly, bt now a days rtd cards
are available widely with plc vendors so we can now a days
use directy without transmitters also,\\thnx,

aditya

Answer / george mathews

Neither temperature transmitter not the thermocouple or Rtd
can control the process. Because as we know Thermocouple and
RTD are nothing but measuring medium , their only work is to
measure the temperature , and for the transmitter it nothing
but a transducer whose only work is to send the measurement
in d form of mA (4 to 20 mA.)

Answer / palanisamy

If you transmit Thermocouple/RTD signal for a longer
distance, it can easily pickup noise & you will not get a
steady reading in the receiving instrument. By providing a
temperature transmitter, we can avoid noise pickup.

Answer / chandrakant kale

WE GENERALLY NEED TO CONTROL THE PROCESS PARAMETER
(TEMPERATURE) SO FOR THAT WE NEED TRANSDUCER.WHICH SEND 4-20
MA TO THE DEVICE WHICH IS TO BE CONTREOLLED. TC IS ONLY FOR
SENSING TEMP.

Why the industry's standard current standards are from 4mA to 20mA,not from 0mA or any other range?

3 Answers  

how to derive kg/cm2 to mmwc? complete derivation.

11 Answers   L&T,

How is SmartPlant Instrumentation related to INtools?

4 Answers   TCS,

Can a Differential Pressure Transmitter be used as a normal pressure transmitter??

3 Answers  

1)how can calibrate temperature transmitter? 2)how can calibrate flow transmitter? 3)how can calibrate level transmitter?

3 Answers   ccic, Emerson, JK Pharma, NIGC, Rockwell, UltraTech,

one rtd sensor which is connected at middle of distillation column where actual temp. is 100deg but when we tight this sensor at thermowell end it goes down to 90 deg & when remove from the thermowell(but sensor end dipped in well) showing actual reading, what is reason?

3 Answers  

What is Integral and Derivative control?

5 Answers   Qatar Petroleums,

please tel me the calibration of pneumatic controler.

0 Answers  

What is pipe schedule? What are all effects its having in the valve? how do we take care of pipe sch in case if the customer dint specify in the data sheet. What we need assume and in what basis?

3 Answers  

i want use pressure transmitter for flow ,how?

5 Answers   Gasco,

what is the working principle of dis-placer type level transmitter

1 Answers   Sendan,

What is furnace draft control?

0 Answers