Why we use 250 ohm resister in series
hart communicator?
Answer Posted / carl_ellis
Answer #2 is not correct because the HART communicator is
not an analog input, it does not use a 1-5Vdc signal. A
HART communicator gets and display a transmitter's primary
variable (or other variables) as a digital value; NOT as an
analog value, not as a 1-5Vdc signal developed across an
analog input's resistor. I repeat, HART communications is
NOT analog in nature, it is digital.
The HART Foundation specifies a minimum resistance of 230
ohms, as described in answer #1, in order to develop the
1200 baud HART signal, that rides on top of the DC loop
current signal.
It's easy to prove that 250 ohms (for 1-5Vdc) is not a
requirement for HART communications as a bench test.
Take a 2 wire loop powered HART transmitter, connect a DC
power supply and use a 330 ohm resistor in series in the
loop. The communicator will work and the primary process
variable will be correct. Then try a 470 ohm resistor.
The 470 ohm resistor will work, as well, and the primary
variable will be correct.
| Is This Answer Correct ? | 7 Yes | 1 No |
Post New Answer View All Answers
what is maxdna ?. explain about the software details.
What is defferent betwen ESP &PCP PUMP .HOW IT IS WORK?
where are following valves are applicable to install. can any valve be installed any line. globe valve butterfly valve boll valve gate valve
What care will you take in the installation of control valves,SCADA,DCS and FOC in Oil and Gas Project?
Exothermic reaction./ endothermic reaction
State some of balance principle’ advantages?
Draw a simple circuit for a well head control panel used to protect the well against fire, leak, blockage, ESD, & controls the operation of one downhole & one surface safety valve. Explain the operation and controls
what is KV and XV valve
draw shematic diagram of c/v positioner(smart type)?
How many types of sensor
How to calibration coriolis flow meter?
Can anybody tell me how to select the size of earthing cable for DCS & PLC system.Please tell me any relevant answer here or mail it to me.
In turbine what does term CDP, NI, NH, HSSOC means.
why we are using magnet for calibration of gas detector?
what is effect of specific gravity in differential level transmitter , explain formula related with this .