difference between null and deflecting instrument.
Answers were Sorted based on User's Feedback
Answer / nupur
A null type instrument as compared to deflection type
instrument has...which of the following.?
.(1)a higher accuracy(2)a lower reliability(3)a faster
response(4)all of the above?
Is This Answer Correct ? | 174 Yes | 12 No |
Answer / nupur
A null type instruments are more accurate than deflection types.
Is This Answer Correct ? | 66 Yes | 10 No |
Answer / sandy
The accuracy of these two instruments depends on different
things. For the Null type ins it depends on the linearity
and calibration of the spring, while for the second it
relies on the calibration of the weights. As calibration of
weights is much easier than careful choice and calibration
of a linear-characteristic spring, this means that the
second type of instrument will normally be the more
accurate. This is in accordance with the general rule that
null-type instruments are more accurate than deflection
types.
Is This Answer Correct ? | 48 Yes | 20 No |
Answer / jasmine
The pressure gauge is a good example of a deflection-type instrument, where the value of the quantity being measured is displayed in terms of the amount of movement of a pointer. An alternative type of pressure gauge is the dead-weight gauge which is a null-type instrument. Here, weights are put on top of the piston until the downward force balances the fluid pressure. Weights are added until the piston reaches a datum level, known as the null point. Pressure measurement is made in terms of the value of the weights needed to reach this null position.
The accuracy of these two instruments depends on different things. For the first one it depends on the linearity and calibration of the spring, whilst for the second it relies on the calibration of the weights. As calibration of weights is much easier than careful choice and calibration of a linear-characteristic spring, this means that the second type of instrument will normally be the more accurate. This is in accordance with the general rule that null-type instruments are more accurate than deflection types.
In terms of usage, the deflection-type instrument is clearly more convenient. It is far simpler to read the position of a pointer against a scale than to add and subtract weights until a null point is reached. A deflection-type instrument is therefore the one that would normally be used in the workplace. However, for calibration duties, the null-type instrument is preferable because of its superior accuracy. The extra effort required to use such an instrument is perfectly acceptable in this case because of the infrequent nature of calibration operations.
Is This Answer Correct ? | 20 Yes | 14 No |
Answer / ramesh.a
the null ins is gives the different between two
voltage/current......
the deflecting instrument is gives the value of the
measurand like voltage/current.....
Is This Answer Correct ? | 30 Yes | 30 No |
how feedback signal frm rtd can be use for 2 purpose, i.e. 1for local monitoring and 2nd for controlling in dcs.so how many wired RTD can be used
if in a level tx height is given, how u calculate the ranges of the tx?
2 Answers Bombay Rayon Fashions, Invensys,
on interface level transmitter model(RTG3302-EMERSON) What is threshold valve how can we select correct threshold value T1,T2,T3,T4 When interface water & hydro carbon
i have been asked by QAFCO to appear for interview for thy post of Instrument Designer(INTOOLS)..i m engineering graduate with 5 years exp. in design engineering.Will this job profile suit me??i need all ur help n suggestions for thy same?
What is intrinsic safety mean.
what will be the output of the temparature transmitter if temp is 120 degre celcius.
1 Answers Base Automation, NTPC, PDO,
what is the PC interface and software for connection to ABB logic module “ LM011-CE18RAC “ ( for Programming ) ??
yokogawa Temperature transmitter showing Error 15 which is Reverse Cal Fail (confirmation calculation result is bad) in manual they mentioned reasion That the output goes to the value set by hardware failure mode jumper. How can solve this problem ? anybody can say solution
How to calibrate Toxic gas detector?
Can you explain drawbacks between P,I,D & PID controller
1 Answers JSW, Priya Cement, TPL,
Determine the manipulated variable, controlled variable, and the measured variable given a description of various typical industrial processes.
what is the meaning if the control valve CV is 27,in terms of selecting procedure?