EI 1302(2 MARKS) UNIT V

Unit V

1. Classify the recorders used in instrumentation?
Recorders may be classified as
Analog recorders
Digital recorders
Analog recorders classified as
Graphic recorders
Oscillographic recorders
Magnetic recorders
Digital recorders are classified as
Incremental recorders
Synchronous recorders

2. What are the basic components present in magnetic recorders?
Basic components of magnetic recorders are
Recording head
magnetic tape
Reproducing head
tape transport mechanism and
conditioning devices

3. State the principle of FM recording?
In the FM recording the carrier frequency fc is modulated by the input signal. FM recording uses the variation of frequency to carry the required information instead of varying the amplitude the modulated signal is then recorded using the recording head in normal way the reproducing head reproduced signal is passed through FM demodulator, low pass filter to get original signal
4. What are the advantages of digital data recording?
• recorder and another amplifier in reproducer to condition signal
• The digital data recorders have high accuracy
• They are insensitive to speed of magnetic tape
• The process of recording digitally coded number is simple it requires amplifier in The information can be directly fed to computer for processing and control
• Nonlinearity and distroction problems do not exit

5 What are the advantages of LCD?
• Power consumed is of the order of few micro watt
• The LCD The response time of LCD’ stypiccally range between 10 and 100ns
• They has twisted numatic structure, very small voltage, typically >10v, are sufficient to align the molecules.

6 What are the applications of X-Y recorders?
• Speed-torque characteristics of motor
• Regulation of power supply.
• Plottingcharacterstics of active devices such as vacuum tubes, transistor, rectifiers, diodes.
• Plotting stress strain curves, hysterics curve etc...
• Electrical characteristics of material such as resistance Vs temperature
7 Explain paper drive and chart speed mechanism?
Paper drive system:
The paper drive system should move the paper at uniform speed Aspiring wound mechanism may be used in most recorders asynoshronous motor is used for driving the paper
Chart speed:
Chart speed is a term used to express the rate at which the recording paper in a strip chart recorders it is expressed in in/s or the period of the recorded signal can be calculated as
Period = time/cycle
= time base/chart speed

8 What is data logger & mention its application?
In industries and process plants data logger are becoming very popular so as to monitor display ,measure, store and control different process variable data is nothing but output from different transducer and log means permanent storage of this data the data logger handle digital information hence it require fast ,accurate analog to digital conversion technique.

9 Name the methods of recording?
Direct recording.
FM recording
PDM recording
Digital tape recording

10 State the purpose of play back amplifier in digital recorder?
The playback amplifier raises the voltage level and shortens the rise time.

11 What is Non return zero?
The magnetic tape is magnetically saturated either in positive or in negative direction in NRZ format for logic 1 representation there is no change in flux binary number 10101100 is represented by NRZ format as shown



12 What is the principle of nixie tube?
Non planner display is the nixie tube it is a gaseous glow tube having a set of electrode, each shaped in the form of digit. The selected electrodes are surrounded by a gaseous discharge or glow when the digit it is selected the electrode are stacked one behind the other and hence the various digit appear in different planes in the readout
13 Explain cold cathode display?
They are also known as neon gas discharge displays when a negative voltage is applied to a gas, the gas molecules breakdown and discharge takes place

14 State the primary function of magnetic recorders?
Used for a high frequency signal recording
in these recorders data is in a way that it can be reproduced in electrical form any time

15. State the principle of magnetic Recorder?
 The principle of magnetic tape recording in a way that it can be reproduced in electrical form any time
 The principle of magnetic tape recording is when a magnetic tape is passed through a recording head the signal to be recorded appears as some magnetic pattern on the tape this magnetic pattern is in accordance with the variation of signal recording current . The recorded signal can be reproduced back by passing the same tape through a reproducing head where the voltage is induced corresponding to the magnetic pattern on the tape.
16 Define multiplexed display?
By time sharing the decoder used for driving the digital digits, it is possible to considerably reduce the count of the components and interconnection in display system, input in BCD form applied to latch &their output are fed to single BCD to seven segment decoder at any instant how ever only one of the digit is displayed as selected by the decoder output from the scan controller
17) Difference between cold cathode &incandescent display?
Cold cathode display Incandescent display
• Here cathode and anode arrangement is used • They have 7 segment filaments contain with in a single vacuum envelope
• Gas is used for discharge • Instead of neon gas ,vacuum is present
• Display is in orange color • Display is in any color accord to our requirement
(18) Difference between X-Y & digital recorders?
Analog X-Y Digital X-Y
• Servo motor is used • Stepper motor is used
• No different color outputs are obtain • Record no of input simultaneously with different color
• Instantaneous relationship between 2 physical quantities can be recorded • It can record or draw grids axis

(19) Difference between LCD & LED?
LED LCD
• It is a active device that generates light • It is a passive device that modified the light by scattering
• PN junction diodes mode of galliumarsinide phospide • In twisted neamutaic display the LCD is sandwiched between 2 pies of glass

(20) Difference between seven segment & dot matrix display?
Seven segment display Dot matrix display
• It is used for numeric display • It is used for numeric & alpha numeric characters
• A segmental display form the digit to be displayed • Various matrix display digit to be displayed

(21) Difference between single point & multipoint recorders?
Single point recorders Multi point recorders
• Recording single input only • Recording several inputs
• It is recording with respect to time only • It recorders variable quantities with respect to another variable quantity
• The trace of curve is single continuous curve • The trace of curve are multi curves not in continuous