in current transmitter why we use 4-20ma ???
Answers were Sorted based on User's Feedback
Answer / kinjalkumar chauhan
1) because output is linear in that region.
2) if communication wire brokeup then we come to know that.
| Is This Answer Correct ? | 5 Yes | 1 No |
1) A current signal has the same current in all parts of the loop, unlike a voltage that drop voltage over distance, which provides reliability that a voltage signal does not.
2) A current signal is more resistant to noise pickup than a voltage signal is.
3) A live zero at 4mA allows for '2 wire operation', where the power for the loop uses the same two loop wires as the signal, a critically important feature for geographically dispersed industries like oil & gas, steel, paper and mining. 2 wire loop powered transmitters use about 3.5 or 3.6mA of current to operate the transmitter.
4) A live zero is a diagnostic detection of an open circuit
5) 4-20mA is a low enough current with limited energy that transmitters can be designed to operate intrinsically safe in hazardous areas with the appropriate barrier protection from faults in the safe area.
6) The DC current signal is suitable for superimposing a modulated FSK signal used by HART for digital communications that allow for configuration, troubleshooting, diagnostics or multivariable data transmission, all while retaining an analog primary variable
7) 4-20mA drives considerable sized loads at fairly low DC voltages, allowing for a relatively long distance signal path (1-2km depending on wire size). 20mA has a relatively low IR drop.
| Is This Answer Correct ? | 6 Yes | 2 No |
Identify the electrical variable that is either directly or inferentially used by various instruments to determine the value of a measured variable.
Please asked me How calculate DCS controller memory.
what is the calibration procedure for transweigh make weigh feeder?
Whether the DI, DOs shields can be connected with Analog Input Shield Earthpit?
How to calculate mmwc values into tonnes?
How to check the SCAN time of DCS ,n dont give therotical answers .How to check the SCAN time of DCS during FAT?
What is the difference in clamp on type and inline type ultrasonic flow transmitter.
What is difference between loop and zone ?
What is PID tunning
HOW TO CHECK THERMOCOUPLE AND RTD & WHAT IS THE DIFFERENCE BETWEEN THERMOCOUPLE AND RTD
send me HPCL paper
what is gas metering system? gas chromatograph? and gas compressors?
Civil Engineering (5086)
Mechanical Engineering (4456)
Electrical Engineering (16639)
Electronics Communications (3918)
Chemical Engineering (1095)
Aeronautical Engineering (239)
Bio Engineering (96)
Metallurgy (361)
Industrial Engineering (259)
Instrumentation (3014)
Automobile Engineering (332)
Mechatronics Engineering (97)
Marine Engineering (124)
Power Plant Engineering (172)
Textile Engineering (575)
Production Engineering (25)
Satellite Systems Engineering (106)
Engineering AllOther (1379)