ion Im Analogue Chart Recorders for Electrical

8/8/2019 ion Im Analogue Chart Recorders for Electrical

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PRESENTATION # 01

SEC : A

PRESENTED BY :

FATIMA RAFIQUE :EE 01083-128

FARIHA DURRANI:

EE -01083-019


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ANALOGUE CHART RECORDERS

FOR ELECTRICAL

SIGNALS

CHAPTER # 8 : BERLIN . GETZ

CHAPTER # 11 ALAN . S . MORISS


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Analog recorders are used to provide acontinuous, permanent graphic recordof a signals amplitude as a function of

time. They are a long-established means of

making permanent records of electricalsignals in simple, cheap and reliableway.

Three types of ghraphical recordinginstruments that are in commom use.

ANALOG RECORDER


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They are :

(a). The galvanometer recorder

(b). The self- balancing recorder(c). The x-y recorder

These instruments may use

(1). Long rolled strip

(2). Circular disc chart

(3). Rectangular sheet


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Stripped chart :Strip chart is a roll or strip of paper that is passed

linearly beneath one or more pens. As the signalchanges the pens deflect producing the resultant

chart. Strip chart are well suited for recording of

continuous processes.


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A circular chart records data in a circular

format. The paper is spun beneath one or

more pens. The pens are deflected in

proportion to the varying signal resulting

in a circular chart.

Circular chart:


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Strip chart recorderalso include a secondstylus , called anEVEVTMARKER

These chart recorders have a driver motor

that moves them at a constant speed. This

rate known as CHART SPEED. It is

generally expressed in length per time.

(E.g: milimeter per second ) and in case of

circular chart recorder it isRevolution per

unit time


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In all three cases , a suitable scale is usually printed on chart

The marking of the chart can be done with an

(i). Inked stylus ( least expensive but require

frequent cleaning)

(ii). Pressure stylus (requires specialsensitized

(iii). Light beam paper ; requires lessattention(iv).Heated stylus no ink spillage but

expensive and complex )


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GALVANOMETERRECORDER


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Galvanometer is both strip and circularchart recorder.

It is more compact and have a highfrequency response than self- balancingrecorder

Its maximum frequency response is100Hz

And has maximum accuracy of1% to2%


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WORKING OF GALVANOMETER

RECORDER

In galvanometer recorder, the marking stylus or pen ismounted at the end of the pointer of the moving coil meter.

The measured signal

is applied to the coil,

and the Angular

deflection of this and

its attached pen is

propotional

the magnitude

of the signal

applied.


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SELF-BALANCINGRECORDER


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the self balancing recorder uses anelectrical circuit that drives a motorizedbalanced control, continously

maintaining the potential balance Self balancing recorder eliminates most

of the inaccuracy inherent in the dragof the marking stylus

But self balancing is too slow andexpensive than galvanometer


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REFRENCE VOLTAGE

Measured

signalError

Error

amplifier

Servo

amplifier

pen


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X Y RECORDER


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X-Y recorders accept two inputs and create

a chart or graph of one input versus the

other. They are commonly used to

determine the relationship between the

two inputs. For example in a chemical

process, an X-Y recorder might be used to

monitor the effect temperature has on the

pressure of the process.


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Two closed loop servo syst-

em drives the marking stylus.

X-y recorder is stationaryRectangular Chart recorder.and

paper is held Either by vaccum

or elecrtostatic attraction.

Many x-y recorder includea time base so that a single sign-

al can be plotted against time


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WORKING OF X-Y RECORDER

Servo

amplifier

balance

balance

y

x

pen

Y-axis servo

motor

Refrence

voltage

Servo

amplifier X- axis servo

motor


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For an X-Y recorder, typical parameters

include the following:-

*input impedance: 1 Mohm, each

channel

*accuracy = 0.5% of full scale

*resettability: 0.2 %

*overshoot: less than 2% of full scale*slewing speed: greater than 20

inches per second


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The range of signals insufficient to overcomeinertia is referred to as theDEADBANDZONE

voltage

Input

Penposition

Deadband

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ion Im Analogue Chart Recorders for Electrical