This document describes a project to maintain and calibrate an I/P and P/I converter setup. The setup is used to understand electronic and pneumatic signal conversion. It consists of I/P and P/I converters, pressure gauges, an air regulator, and a digital calibrator. The document provides details on the components, including descriptions of a current source, air filter regulator, pressure gauges, and I/P converter. It explains the working principles and applications of the setup for process control. The overall purpose is to study the linearity, hysteresis, accuracy and repeatability of the I/P converter.

1. PROJECT
MAINTENANCE OF I/PAND P/I CONVERTER
AND CALIBRATION
Government Polytechnic Mumbai
GUIDED BY :-
V.K.PAWAR
PROJECT BY :-
FS15IS007 RAYEEN ALI
FS15IS013
FS15IS021
FS15IS022

2. Description
The I/P and P/I converter setup is designed for understanding basic
principles of electronic and pneumatic signal conversion. The setup consists of
I/P converter, P/I converter, digital calibrator, pressure gauges and air regulator
and air filter regulator. The Digital calibrator is used as current source to supply
4-20 mA DC to I/P converter and to measure the output of pressure gauge. The
input pressure 3-15 psi is P/I converter to 4–20 mA output indicator. I/P converter
gives the output as 3-15 psig and P/I converter gives output as 4-20 mA DC.

3. Input PressureVent
P/I Converter
Filter Regulator
Regulator
I/P Converter
Supply Pressure Output Pressure
Air supply Digital calibrator
BLOCK DIAGRAM :-

4. CURRENT SOURCE
I TO P CONVERTER CONTROL
AFR
I TO P CONVERTER
PRESSURE GAUGE

5. CURRENT SOURCE
A current source is an electronic circuit that
delivers or absorbs an electric current which is
independent of the voltage across it. A current
source is the dual of a voltage source. The term,
constant-current sink, is sometimes used
for sources fed from a negative voltage supply.
The DC current source block represents an ideal current source
that is powerful enough to maintain specified current through it
regardless of the voltage across the source.
You specify the output current by using the constant
current parameter, which can be positive or negative.
The positive direction of the current flow is indicated by the
arrow.
Description :-

6. What is Air Filter Regulator ?
 A device that used primarily for regulate pressure and
filtering the air for stable source of air to process control
equipmentsuch as current to pneumatic (I/P) transducers and
control valvepositioners.

7. Important to regulate pressure :-
• Pressure is one of the most important aspects of ANY piping
system.
•If pressure is too low, the system is powerless.
•And if it is too high, overpressure affects filters, tools,
sprayheads, instruments any vital tool in a liquid piping
system.

8. Simple definition:
• A pressure regulator is a normally-open valve
that takes a high inlet pressure and converts it to a
lower, pre-set downstream pressure.

9. Uses of a Pressure Regulator:-
-
1. As a controlelement
toensure thatdownstream pressuredoes notexceed a
set point.
-
2. As a safetydevice
to protect equipment from harmfuloverpressure.
-
3. Regulate to thecorrectpressurerange
so thata flow system orpieceof equipmentcan
operate safely andeffectively.

10. Filter (general principle)
 Separate and collect
contaminants
 Angled louvers spin the
air as it enters the bowl
 Water droplets and large
solid particles spun
outwards against bowl
and run to the bottom
 Baffle prevents turbulent
air splashing water on to
the filter element
 Element traps finer solid
particles
LOUV
ER
FILTER
WATER PARTICLES
DRAIN PLUG
SYMBOL

11. Filter Regulator
 Filter and regulator
designed as a single unit
 Air is first filtered then
directed to the primary
side of the regulator
 Pressure is then reduced
to a working value
 Only one unit to install
 Cost saving when
compared to two separate
units

12.  A “current to pressure” converter (I/P) converts an analog signal (4 to 20 mA
DC) to a proportional linear pneumatic output (3 to 15 psig). Its purpose is to
translate the analog output from a control system into a precise, repeatable
pressure value to control pneumatic actuators/operators, pneumatic valves,
dampers, vanes etc.
Idea about I/P CONVERTER :-

13. ◊ Working Principle :-
•External 24 VDC 230 +/- 10 VAC, 50 Hz, 1
phase
power supply & Clean, oil & moisture free
air, pressure 2 Bar, consumption 50 LPH
air supply required.
•Converts an analog signal (4 to 20 mA)to
a proportional linear pneumatic output
(3 to 15 psig).
•Electromagnetic force balance deliver
consistently high performance.
•Reliable, repeatable, accurate process.
•Force balance principle.
•Flapper-nozzle assembly.
•Zero adjustment(turning a screw).
•Span adjustment (varying a
potentiometer).
• An integral volume flow booster
provides.

14. The pressure gauges
The pressure gauge instrument is used for measuring
the condition of a fluid (liquid or gas).
Pressure gauge accessories are as follows:
• Diaphragms
• Bellows
• Bourdon Tube

15. Diaphragms

16. Bellows
Bellows (fig. 3) are made with a number of convolutions from a
soft material and one end of it is fixed, whenever air can go
through a port. The other end of the bellows is free to move.

17. Bourdon Tube
It is basically consisted of a C-shaped hollow tube, whose one
end is fixed and connected to the pressure tapping, the other
end free.

18. Introduction
The pressure measuring cell converting the
pressure into an electrical signal is the heart of the
pressure sensor.
Pressure transmitter
PRESSURE TRANSMITTER

19. Pressure transmitters
A pressure transducer, often called a pressure
transmitter, is a transducer that converts pressure
into an analog electrical signal.

20. Pressure transmitter :-
strain gauge :-

21. Signal Conditioning Circuits
We know that signal conditioning is a process in which signals from different sensors
are transferred into a form necessary to interface with other modules of system.
For example, we know that thermocouple produces very low output voltage and this
voltage is not sufficient to operate the other controlling modules. Therefore there is
need to amplify such signals. For this purpose we use different signal conditioning
circuits. In case of thermocouple, we have to use amplifier, linearization circuits, etc.
the purpose of using linearization circuits is that, thermocouple has non linear
characteristics but in most of the cases we need linear controlling action.

23. Signal Conditioning Circuits:
There are different types of signal conditioning operations such as amplification,
filtering, isolation, linearization, excitation, etc. we will discuss all these operation
one by one.
Amplification
We know that most of the sensors produce output in the form of change in
resistance, voltage or current. All these parameters are having very low strength i.e.
very small voltage in case of thermocouple, small change in resistance in case of
RTD, etc. Therefore we have use current or voltage amplifiers in case of sensors
which produces output in the form of current or voltage.
If the sensor produces output in the form of change in resistance (such as resistance
thermometer) we have to use bridge amplifiers. We can make use of operational
amplifiers to amplify the signal.
Filtering
Another important signal conditioning circuit is filter. As mentioned earlier most
of the sensor produces very low output and therefore electromagnetic noise may get
added in the original output. To remove the electromagnetic noise from sensor
output we have to use different filter circuits. Filter circuits eliminates noise i.e.
undesired frequency components from original signal without affecting it.
Active filters, passive filters, bypass filters are the common types of filter circuits.

24.  Application : -
 Study of Linearity, Hysteresis, Accuracy and Repeatability of I/P
 converter.
 Study of flapper nozzle system.
 In various industrial field, we use to measure
ΩOmega IP
Converter
MANUFACTURER:
Liquid-level control system.