week 2

Question 1

Need for transmitters

Answer 1

They convert a measured value into a proportional standard instrument signal

Question 2

Diaphragm

Answer 2

moves a small distance when pressure is applied across it from the process

Question 3

Force bar

Answer 3

pivots like a see saw when diaphragm moves, pushing flapper closer to nozzle

Question 4

Flapper/nozzle

Answer 4

flapper restricts air from venting out of nozzle which creates a greater back pressure

Question 5

Restrictor

Answer 5

smaller hole within the nozzle giving a greater pressure drop when the flapper moves (0.2 to 1.0 bar range)

Question 6

Value restrictor relay

Answer 6

boost output of air to value signal while keeping output and back pressure at the same pressure

Question 7

maximum movement of the flapper

Answer 7

10/1000 of an inch

Question 8

pneumatic transmitters disadvantages

Answer 8

slow response,
lots of moving parts,
high maintenance

Question 9

pneumatic transmitters advantages

Answer 9

safe in hazardous areas

Question 10

calibration of pneumatic transmitters

Answer 10

use a test gauge

Question 11

TX(transmitter) range

Answer 11

0 to 300 mbar

Question 12

electronic transmitter

Answer 12

diaphragms move the capacitor plates when pressure is applied

Question 13

electrical transmitter calibration

Answer 13

both input and the output must be measured

Question 14

advantages of electrical transmitter

Answer 14

fast response,
few moving parts,

Question 15

disadvantages of electrical transmitter

Answer 15

requires special standard to operate in hazardous areas

Question 16

voltage dropping resistors

Answer 16

if the resistor is removed then the receiver device will show full scale deflection (100% of the scale)