Skip to main content

Various Static Characteristics

1. Accuracy :-

It is a degree of Closeness with which the reading on the instrument approaches to the true value of the quantity to be measured.

eg. :- Suppose you have a conductor which diameter is of 3.325 mm exactly. now when you measure it by a micrometer whose least count is of 10 micro meter or a 0.01 mm, then you may get the reading as 3.32 mm which is somewhat correct, but not accurate. so to measure it you need a micrometer whose least count should be 1 micro meter(0.001 mm) or a 5 micro meter(0.005 mm ) then you can get more accurate readings.

2.Sensitivity:-

Sensitivity is defined as a response of the instrument to the smallest change in the input variable.

It is also defined as a ratio of change in the output of an instrument to the change in the value of the quantity to be measured.

mathematically :-

Sensitivity :- change in Output / change in input.

eg. :- suppose you have a thermocouple which can measure a temperature from 0 degree Celsius to 45 degree Celsius, and which can give a maximum output reading as 5 volt for maximum input variation.

so the sensitivity of the instrument is now :-
maximum output variation / maximum input variation.
= 5/45 = 0.11 volt/degree Celsius.

3. Precision:-

The Precision is refereed as the closeness of the measurement to each other. or it is defined as the quantity, condition or fact of being exact.

You may define the precision as the degree to which the repeated measurements under the unchanged condition shows the same results.

Note :-  A measurement system cant be accurate and precise at the same time. 

eg :- suppose you are checking the voltage of a battery and taken the readings are like 12.15V, 12.18V, 12.14V,12.16V, 12.17V, 12.16V.
now you can see the readings on voltmeter are not same but nearly close to each other. so we can say the readings are precise.

4. linearity:-

Linearity is nothing but the consistency of the accuracy over full range of measurements.

eg:-Suppose you are getting the same change in output measurement for every change in the input quantity then it is called linearity of instrument.
This property of instrument is very very useful in the scientific work.

5. Reproducibility:-

Reproducibility of the system or the instrument is its ability to produce same output if the same input is given to it.

Note :- The Reproducibility does not focus on the, Location of measurement, Surrounding climatic conditions, and the person who is taking measurement.

6. Repeatability :-

Repeatability is defined as the variation in the repeated measurement over a same subject under the same identical conditions over a short period of time.

Note :-  In this characteristic, measurement are taken - on same measurement location, same place, same measurement procedure, same observer, same measurement instrument, and measurement repetition are taken over a short period of time.

7. Resolution:-

Ability of the measurement system to detect and faithfully indicate small changes in the characteristics of the measurement results.

8. Threshold :-

Threshold is the amount of measurement change required before a measurement instrument react to a change in measurement output or produce a specific result.

Note :- 
Resolution :- it is a minimum change in input quantity measured by instrument.
threshold :- it is a minimum input measured by an instrument.

9. Drift:-

Drift is a gradual shift in the indication or record of the instrument over an extended period of time, during which the true value of the variable does not change.

Drift is a undesirable quantity in the instrument.

10. Stability :-

It is the ability of the instrument to maintain a certain physical property at a constant value, while rejecting any disturbances in the environment.

11. Tolerance :-

Tolerance refers to the total allowable error with in the instrument for a input.

12. range or span of the instrument:-

Span or the range of the instrument is defined as the algebraic difference between the lower and upper range values of instrument.






Labels:

Comments

Post a Comment

Popular posts from this blog

Timers in Siemens PLC Simatic manager

Timer :- Timer is nothing but a specialized clock in a programming software used to count the preset time intervals. In   Siemens PLC we have various ty pes of timers as :- 1) S_PULSE(Pulse timer), 2) S_PEXT(Extended Pulse Timer), 3) S_ODT(On Delay Timer), 4) S_ODTS(Retentive On Delay Timer), 5) S_OFFDT(Off Delay Timer). You must find out another five instruction sets in Timer Block in Simatic Manager STEP 7 as :- -(SP) pulse timer coil, -(SE) extended pulse timer coil, -(SD) on delay timer coil, -(SS) retentive on delay timer coil, -(SF) off delay timer coil. 1) S_PULSE(Pulse timer) :- S_PULSE Timer   Above Fig Shows how to use this timer in programming software,in this fig i have used 5 sec as a preset value, If you want to change it replace the 5 with any duration you want in S5T# 5 S.    In S_PULSE timer if input to timer is ON then timer starts Counting time as well as we get the Output at the instant the input is made ON. In t...
Post a Comment
Read more

HOW TO DOWNLOAD AND INSTALL WONDERWARE FOR WINDOWS 8,7,10.

##You can Download a ZIP file of the software From Below link. https://drive.google.com/file/d/159y8W0c_bw0vvf1DNDQ08_QsLZ9h2Tb1/view?usp=sharing 1 ) You Can Also Watch a Video Tutorial of it  below. 2) You can also read out steps from below :-
2 comments
Read more

Bit Logic Instruction in Simatic manager

There are total 14 instructions under the bit logic instruction like NO contact, NC contact, SR flip-flop, RS flip-flop,invert power flow etc. lets see the detailed use of them.  A) Normally open contact :- Normally open contacts are closed when the bit value stored at the specific address is equal to 1 (one)(here the specific address refers to the address assigned to the NO contact), when we press the Normally open contact assigned to the specific address then it becomes functionally closed and we get supply. here in below fig. when we press the NO contact I0.0 then Output Q0.0 gets ON and when we release the input I0.0 then Output gets OFF. B)Normally Closed Contact :- Normally closed contacts are closed when the bit value stored at the specific add, i.e. the address assigned to the NC contact is equal to 0(zero). when we press the Normally closed contact assigned to the specific address then it becomes functionally open and supply is cuts off. NC contact wor...
Post a Comment
Read more