Plc 1 Test 3

Front 1

What are the valves in class made of?

Back 1

Stainless steel and brass.

Front 2

What is the type of valve used in lab? (pos/way etc)

Back 2

2 position, 2 way, normally closed, sol operated.

Front 3

What's the rating of the solenoid used in lab?

Back 3

Continuous.

Front 4

When a solenoid is rated for continuous or intermittent use, what does that mean?

Back 4

Intermittent means that you can't keep it energized forever, it has a duty cycle. Continuous can be energized forever.

Front 5

What's the best type of valve control to use with low pressure?

Back 5

Solenoid controlled.

Front 6

What type of double solenoid valve control will cause a solenoid to burn out if both solenoids are energized at the same time?

Back 6

Solenoid control.

Front 7

What is flow factor? Not as in Cv

Back 7

Gallons per minute with 1 PSI pressure drop.

Front 8

What's the abbreviation for flow factor?

Back 8

Cv

Front 9

What does Cv stand for? Not flow factor.

Back 9

Coefficient of flow

Front 10

What is Cv?

Back 10

Flow factor.

Front 11

What's the standardized unit for gas flow?

Back 11

SCFM

Front 12

What does SCFM stand for?

Back 12

Standard cubic feet per minute.

Front 13

What are the five main parameters to look at when selecting a valve?

Back 13

Temperature, pressure, media compatibility, flow factor, and port size.

Front 14

What type of valve uses a solenoid to shift a pilot valve and the pressure in the system to move the main valve spool?

Back 14

Solenoid controlled pilot operated.

Front 15

If the specific gravity is 1.2, is it denser or less dense than water?

Back 15

More dense.

Front 16

If specific gravity goes up, what happens to flow rate?

Back 16

It goes down.

Front 17

If flow factor (Cv) goes up, what happens to flow rate?

Back 17

It goes up.

Front 18

If pressure drop goes up, what happens to flow rate?

Back 18

It goes up.

Front 19

If using a capacitive probe with a conductive fluid, what must happen?

Back 19

You must wrap one probe in non-conductive material. Teflon.

Front 20

What's a non conductive material typically used to wrap capacitive probes in?

Back 20

Teflon.

Front 21

What does fail safe refer to?

Back 21

The condition of the device if power shuts off.

Front 22

What does P & ID stand for?

Back 22

Piping and instrumentation diagram.

Front 23

What are the categories of level measurement?

Back 23

Direct and indirect, invasive and noninvasive, and point and continuous.

Front 24

What is a point level float switch made up of?

Back 24

A magnet in the float and a Reed switch.

Front 25

If you flip over a point level float switch, what happens?

Back 25

It changes from NO to NC.

Front 26

Do you want the specific gravity of the float switch to be more or less than the specific gravity of the fluid it's in?

Back 26

You want the float's specific gravity to be less.

Front 27

Is the float in our lab switchable between NO and NC?

Back 27

Yes.

Front 28

What are the float switch selection parameters?

Back 28

Temperature, pressure, media compatibility, specific gravity, and volt/amp rating of contact.

Front 29

When using a Reed switch to control an AC inductive load, what should be connected around the inductive load?

Back 29

A MOV.

Front 30

When using a Reed switch to control a DC inductive load, how should a diode be placed around the inductive load?

Back 30

Reverse biased.

Front 31

When a diode is reverse biased, what should be pointing towards the positive?

Back 31

The cathode. (line)

Front 32

When using a Reed switch to control a DC inductive load, what should be placed around the inductive load?

Back 32

A diode.

Front 33

Which is the most common property to measure when indirectly monitoring level?

Back 33

Pressure.

Front 34

Which of these is the float level switch used in lab?

Back 34

D.

Front 35

Which of these is the float level switch used with turbulent fluid?

Back 35

F.

Front 36

Which of these is the float level switch that is side mounted?

Back 36

A.

Front 37

Which of these is the level switch uses a high level frequency across a gap?

Back 37

B.

Front 38

What's the electro-mechanical symbol for a float switch?

Back 38

Front 39

What type of proximity sensor is used in lab to detect the monitor level?

Back 39

Capacitive.

Front 40

What are the four types of probes used to monitor level?

Back 40

Capacitive, conductive, ultra sonic, radar.

Front 41

Is conductive probe point level or continuous level?

Back 41

Point level.

Front 42

What should be true with single capacitive or conductive probe use?

Back 42

The container wall must be conductive.

Front 43

What mA output should you use for a non contact ultrasonic?

Back 43

4-20mA. Why 4 instead of 0?

Hint 43

Because if it stops getting a return signal, after a while it'll turn to 0. This'll tell you something's wrong.

Front 44

Can the non-contact, continuous ultrasonic sensor also act as a point sensor?

Back 44

Yes, any continuous sensor can.

Front 45

When a contact ultrasonic sensor is vertical, where does the fluid have to reach for it to read it?

Back 45

Past the gap.

Front 46

When a contact ultrasonic sensor is horizontal, where does the fluid have to reach for it to read it?

Back 46

1/2 way up.

Front 47

What does a float level switch used with turbulent liquids have?

Back 47

A plastic case.

Front 48

What is point level mA output signal?

Back 48

4 OR 20 mA

Front 49

What's continuous level mA output signal level?

Back 49

4 TO 20mA

Front 50

What does intrinsically safe mean?

Back 50

Not enough to produce ARCs or sparks.

Front 51

What does a bubbler monitor to measure level?

Back 51

Pressure.

Front 52

What type of material is used with a sensor that uses a paddle wheel and a low torque, low speed, synchronous motor?

Back 52

Solids.

Front 53

What type/s of material/s is/are used with a non contact, ultrasonic probe?

Back 53

Solids or liquids.

Front 54

What's the pressure at the bottom of a column of water known as?

Back 54

Hydrostatic head pressure.

Front 55

What happens to the flow rate out of the bottom of an un-pressurized tank as the water level drops?

Back 55

It decreases.

Front 56

What switch characteristic is needed to use one switch to indicate a large separation between high and low levels?

Back 56

A large differential.

Front 57

What's a differential?

Back 57

The amount of change it takes for the switch to switch back and forth.

Front 58

Which level sensor would be good to use at the boundary of two different liquids to detect the level if the bottom liquid?

Back 58

Displacement sensor.

Front 59

How does a valve reduce the water-hammer effect?

Back 59

It closes gradually to not produce sudden stoppage.

Front 60

What is this?

Back 60

A level switch that clamps onto piping.

Front 61

What's this?

Back 61

A tuning fork sensor.

Front 62

Is a tuning fork sensor point level or continuous level?

Back 62

Point level.

Front 63

What does a tuning fork sensor do?

Back 63

Has two vibrating forks that vibrate different when liquid gets to a certain point on them.

Front 64

What is this?

Back 64

A TIR optical sensor.

Front 65

How does a TIR optical sensor work?

Back 65

When out of water, 100% of the light reflects off the glass and back to the sensor. When in liquid, more light escapes. Not as much makes it back to the sensor.

Front 66

Is the TIR optical sensor invasive?

Back 66

Yes.

Front 67

Is the TIR optical sensor point or continuous?

Back 67

Point.

Front 68

What does TIR stand for?

Back 68

Total internal reflective properties.