Answer / rajesh

1.HART is Communication Protocal.it is used to Communicate
the Field Instruments for measuring and Calibrating purpose
2.K Type : 0-1370 degrees
J Type: 0-700 degress
B Type: 200 -1800 deggress
R type: 200 - 2450 degrees
Output of Thermocouple is DC Potential (milli volts)
3.Platimum RTD :PT-100 Range:-270 to 600 degress
Output of RTD is Resistance
4.Temparaure tranmitters
it will receive the sinal from sensor (thermocouple /
RTD) and this signal will convets to 4-20mA or 0-20mA
5.Analog Signal is contioues measuring signal ie it's
measuring Range is 0 to 100%
Digital signal is a Binary form ie. Its state is Either
High (1) or Low(0)
6.in 4 wire Tranmitter Have Seperate exitation Supply is
for its Operation and Output taken for seperately.if the
Tranmitter Elecronic Cercuit is drawing More than 4 ma of
current then it will apply the 4 wire scheme.
in 2 wire Tranmitter working supply and its output is
taken in same cable.ie its working supply is lessthan 4 ma.

Answer / bm

Rajesh has answered 1st 6 qtns. The rest answeres are:
7. Potential contact means there will be a voltage in the
contact whereas potential free contact means that there
won't be any voltage in the contact. The user can take any
voltage basd on the contact rating in the pot free contact
to use further for his application i.e driving some
relay/contactor.
8. Types of flow meters: Rotameter, Venturi FM, Wedge FM,
Ultrasonic FM, Turbine FM, Magnetic FM, Vortex FM, Mass FM.
9. Types of LT: Displacer, GWR LT, Capacitance LT, DP LT,
FMCW LT, Ultrasonic LT.
10. Power/control cable has supply voltage of more than 24V
with no current signal, generally used to actuate
electrical contactors/solenoid valves.
Instrument cable is used to carry "mA" signals or potential
free signals.
11. shield / screen are same to avoid the noise in the pair
cables.
12. Not able to draw here.

Answer / nilesh karpe

Rajesh & BM has ansered 1 to 12 questions:
13.first check the stroke of the valve.ie. fully open &
then full close(for checking smooth operation).
ZERO CALLIBRATION:
at full close see the demand of i/p is 4MA.& output for
this is 0.2 KG/cm2. if not adjust through ZERO pot in i/p.
SPAN CALLLIBRATION:
fully open the valve.at this time the dmd of i/p should
20MA.at this time o/p supply air should 1KG/CM2.if not
adjust the span pot in i/p.
REPEAT THE ABOVE STEPS IN TILL ZERO & SPAN READINGS
MATCH.CHECHK INTERMIDIATE POSITIONS i.e. for dmd signal of
4,8,12,16& 20MA.FOR LINEARITY CHACKING.

Answer / manish kumar singh

Ans.1-
HART
The HART system (and its associated protocol) was originally developed by
Rosemount and is regarded as an open standard, available to all manufacturers. Its
main advantage is that it enables the retention of the existing 4-20mA
instrumentation cabling whilst using, simultaneously, the same wires to carry
digital information superimposed on the analog signal.
HART is a hybrid analog and digital system, as opposed to most field bus systems,
that are purely digital. It uses a Frequency Shift Keying (FSK) technique based on
the Bell 202 standard. Two individual frequencies of 1200 and 2200 Hz,
representing digits ‘1’ and ‘0’ respectively, are used. The average value of the
1200/2400Hz sine wave superimposed on

Answer / bm

Answere by Nilesh is ok

Answer / manish kumar singh

Ans.2- Type
Symbol Materials Temperature limits(°C)
S Pt10%Rh-Pt -50 / 1760

R Pt13%Rh-Pt -50 / 1760

B Pt30%Rh-Pt6%Rh 0 / 1820

E Cr - Co -270 / 1000

J Fe - Co -210 / 1200

K Cr - Al -270 / 1370

T Cu - Co -270 / 400

N Nicrosil-Nisil -270 / 400 (1) 0 /1300 (2)

W3 W3%Re- W25%Re 0 / 2310

W5 W5%Re - W26%Re 0 / 2310

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