Why we use 250 ohm resistor in series with HART protocol
communication?
Answer Posted / zaldy
the 250 ohm resistor converts the 4-20 mA analog signal from the HART transmitter to a 1-5 volt drop to allow the Analog Input card of the DCS or PLC to read the analog signal. The HART digital FSK (Frequency Shift Keying) signal is also present on this line and supplies the HART digital data to the HART modem chip usually present on the same Analog Input card for all new DCSs and PLCs. The Bell 202 protocol used for this FSK
digital circuit needs no terminating or load resistor. The 250 ohm resistor is only for the analog circuit.
| Is This Answer Correct ? | 0 Yes | 2 No |
Post New Answer View All Answers
whatis range of marcury filled tempereture gague
How many are the types of instrument cables in terms of No. of pair.
What is compensation for flow ? Why we use compensation ? What are the factors of different compensation ? We not use then what problems may happen ?
What is Alpha & Beta fctors related to Orifice Plate & its relation with flow?
OBJECTIVE TYPE QUESTIONS OF ANALYTICAL INSTRUMENTATION
where uses EXe /EXd/Exo/Exn/Exp/Exq/EXia
If fire would be inside the plant which fire detector is to detected the fire.
Describe the functions of the Operator Interface including the considerations related to alarming and display layout/configuration/layers.
How many ohms are required for proper earthing?
the pump holds on run indication into the dcs and filed local control panel remote push button condition operaton wrong like when the push button pushing conditions the pump is off and the push button release condition the pump is on totally opposite condition . And control room inside give the stop command into dcs just 1secon relay engage and again normal condition. How can I slove
why is not useing in boiler skin thermocople
can u briefly explain aboutan aryton shunt multirange DC ammeter?
anybody having Qatar Petroleum questions for instrument Technician offshore ....please send me
Sir , i have completed my M.Sc In Instrumentation and presently working in Maintenance department 3 yrs Exp , is there is any possible for work in offshore ..
Hi Friends i need Electronics&Instrumentation Engg question papers for BARC written test by coming 20th May 2008 pls post ur use full info to kkumarei@gmail.com. Or for suggestions pls give one missed call to 9962122264