what is the difference about HART, and 4-20mA signal?

Answers were Sorted based on User's Feedback



what is the difference about HART, and 4-20mA signal?..

Answer / vaibhav v t

HART is a protocol and not a device.It is protocol for
digital signal communnication.
HART compatible transmitter transmits digiatl signal super-
imposed on analog 4-20 mA signal and gives many useful
infoarmation about the transmitter and process parameter
other than output.
You can configure the HART based transmitter using HART
configuator withou removing the trasnmitter from its
location/process.
4-20mA is simple low current signal which is propotional to
calibration range.

Is This Answer Correct ?    53 Yes 3 No

what is the difference about HART, and 4-20mA signal?..

Answer / khaled khreim

The HART Protocol is an acronomy of Highway Adressable
Remote Transducer,it uses the frequancy shift koeying
standard to impose digital communication on top of the 4-
20mA signal.
this enables a two way field communication to take place,
making it possible for additional info rather than the
process variable only.
Hart protocol is a Master/Slave protocol, the HART protocol
can be used in different modes like point to point or
multidrop for communicating info from/to smart fiel device
and the controller, the field device and the controller
should be HART enabled.
In general HART protocol opens two communication channels:
the first one is the 4-20mA normal signal for the measured
value using the 4-20mA current loop. And the second chanel
is the digital signal whic is imposed on the analog one.The
digital signal gives additional info about the field device
such as device status, diagnosis, and other types of info

Is This Answer Correct ?    15 Yes 1 No

what is the difference about HART, and 4-20mA signal?..

Answer / prince

normally in industries we use 4-20mA signal to transfer the
signal from a transmitter to the control system.nowadays
the trasmitters are smart type. so a HART is a device used
to communicate with this smart transmitters to get the data
online or offline. HART is a digital device, so this
digital signal will superimpose on the analog transmiiter
signal without disturbing it.

Is This Answer Correct ?    19 Yes 14 No

what is the difference about HART, and 4-20mA signal?..

Answer / mastersensor80

ANSWER NO 5 IS GOOD,the question about communication
prtotocol, how we trassfer the signal from transmitter to
the DCS,Many ways let us compare between two of them.
a/ 4 - 20 ma (conventila wiring)
b/ HART
HART use the 4 -20 ma but the communication is done via
digital this why we can view many of the transmitter
parameters,this base on PKS (phase hey shifting)refer to
modulation tecniques in communication.

Is This Answer Correct ?    7 Yes 2 No

what is the difference about HART, and 4-20mA signal?..

Answer / mujahid/dinesh

HART compatible transmitter transmits digiatl signal super-
imposed on analog 4-20 mA signal and gives many useful
infoarmation about the transmitter and process parameter
other than output.
this enables a two way field communication to take place,
making it possible for additional info rather than the
process variable only.
Hart protocol is a Master/Slave protocol, the HART protocol
can be used in different modes like point to point or
multidrop for communicating info from/to smart fiel device
and the controller, the field device and the controller
should be HART enabled.

Is This Answer Correct ?    1 Yes 0 No

what is the difference about HART, and 4-20mA signal?..

Answer / haridass

HART Communicator - is a device used to communicate with
the HART / SMART family transmitters, used in the process
control.
* To monitor the PV, Current mA value, Sensor Temperature,
* It is used to re-range the transmitter,
* damping adjustment,
* trimming the sensor of zero/lower/upper ranges.
* create the tags/messages of the transmitter.
* Review the complete details of the transmitter.
* Loop testing the control loop (Indicator/Controller), etc.

Whereas the 4-20 mA source is used for the following:

* To simulate the 4-20 mA signal (For calibration of
control valves, loop testing of the closed/open loop).
* Using the high accuracy 250 ohms resistor, we can get 1-
5vdc as the output which is useful for the DCS input.

Is This Answer Correct ?    11 Yes 12 No

what is the difference about HART, and 4-20mA signal?..

Answer / raj

HART=higely addresaable remote tranduer which works on high
frquency modulatition tech. to calbirate smart
transmitter and 4-20ma signal std.linear signal

Is This Answer Correct ?    5 Yes 20 No

what is the difference about HART, and 4-20mA signal?..

Answer / rp

HART is a communicator/device works on RF Signal whereas 4-
20 mA is a Electrial Analog Signal not a Device/Instrument.

Is This Answer Correct ?    2 Yes 17 No

Post New Answer

More Instrumentation Interview Questions

while am calibrating Drager polytron 2IR flame gas detector occured non zero status.how can i get zero status?

0 Answers   Gasco,


Instrumentation Safe Guarding test. How to determine the interval time of the test. eg:Halfyearly,Every year,Every three years etc.

0 Answers  


give classification of transducer based on type of application

2 Answers  


If boiler drum level transmitter is not working properly what you will do for resolving the problem in plant running condition?

2 Answers  


How to Calibrate Level Switch in field

0 Answers  






WHY RESISTANCE TEMPERATURE DETECTOR IS AN ACTIVE DEVICE

2 Answers  


how to make a calibration for differential pressure

2 Answers  


why we are using MARSHALLING PANEL? what is the role?

5 Answers  


how u choose thermowell lenght n pnumatic C/v size?

0 Answers  


why use 4-20mA in the field of instrumentation?

8 Answers  


What is CNC

1 Answers  


i have 80cm water tank.how can i use DPT as level mesurment.pls give specs for that..? We have air comp.from that moisture comeout to one tank.i want to mesure level of water in that tank and then after operat one sov to dicharge water after high level.

1 Answers  


Categories
  • Civil Engineering Interview Questions Civil Engineering (5084)
  • Mechanical Engineering Interview Questions Mechanical Engineering (4451)
  • Electrical Engineering Interview Questions Electrical Engineering (16631)
  • Electronics Communications Interview Questions Electronics Communications (3918)
  • Chemical Engineering Interview Questions Chemical Engineering (1094)
  • Aeronautical Engineering Interview Questions Aeronautical Engineering (239)
  • Bio Engineering Interview Questions Bio Engineering (96)
  • Metallurgy Interview Questions Metallurgy (361)
  • Industrial Engineering Interview Questions Industrial Engineering (259)
  • Instrumentation Interview Questions Instrumentation (3014)
  • Automobile Engineering Interview Questions Automobile Engineering (332)
  • Mechatronics Engineering Interview Questions Mechatronics Engineering (97)
  • Marine Engineering Interview Questions Marine Engineering (124)
  • Power Plant Engineering Interview Questions Power Plant Engineering (172)
  • Textile Engineering Interview Questions Textile Engineering (575)
  • Production Engineering Interview Questions Production Engineering (25)
  • Satellite Systems Engineering Interview Questions Satellite Systems Engineering (106)
  • Engineering AllOther Interview Questions Engineering AllOther (1379)