1. How many output signals do wew have in process control?
2. Could you write down the names of the pre-commissioning
and commissioning stage test instruments and explain them
(more than 5 items)?
3. What is the first step to commission a transmitter on
service?
4. What is RTD?
5. Find the output value in MA of a temperature transmitter
(RTD Type) at 120degree celius?
6. What is the O/P signal of a pneumatic transmitter?
7. What is the O/P signal of an elctronic transmitter?
8. What is the close loop and open loon?
Answers were Sorted based on User's Feedback
1. Two output signals are used in process control -
analogue and digital.
2. RTD - Resistance Temperature Detector for temperature
measurement upto 600°C.
3. O/P signal for pneumatic transmitter is pneumatic signal
3 - 15 psi
4. O/P signal for electronic transmitter is electrical
signal 4 - 20 mA, 1 - 5 volt.
5. Close loop having sensor, transmitter, controller, and
controlling element (like control valve, on off valve,
damper, servo motor). Open loop does not have controlling
element. open loop is used for only indication in control
system.
| Is This Answer Correct ? | 21 Yes | 0 No |
Answer / biswarup das
Answer of Ques No.5)) Transmitter(Tx) o/p depends on
calibration range. If the Tx is calibrated in the range
0-120degC. Then it will show 20ma when the actual
temperature would be 120degC.
| Is This Answer Correct ? | 6 Yes | 0 No |
Answer / kalla anil kumar,jeypore
1- it may analog and digital, or
2- lot of test instruments like pressure calibrator dead weght testor,(DRUCK),temperator calibrator DECODE BOX,temp bath,For control valve mA source,for vabration (vabolator) etc.
3- we have know the tag,location and application of transmitter,
4-RTD- Resistance temperature detector, it is used up -200 to 600 deg C,
5- first we should know transmitter Range, then we calculate mA, if the range is 120 then 0deg 4mA,30deg 8mA,60deg 12mA,90deg 16mA and 120Deg 20mA,
6- .2 to 1 kg/cm2 or 3 to 15psi
7- 0 to 20mA, 4 to 20mA
8- in a close loop PID control,transmitter, and final control element like control valve,on/off valve, and MOV etc, it will work on auto there will be set valve then controlling out put will come from PID-C, in open loop there will be no set point we have control by manual,
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / p.sharathreddy
4. o/p signal of electronic transmitter is 4-20 mA and 1-10 mV
dc
| Is This Answer Correct ? | 1 Yes | 8 No |
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