Epri A Flashcards
1
Q
Sometimes out of necessity, a controller will be performing the control functions for several processes this control is called
A
shared controller
2
Q
a ____ signal is often referred to as an ON/OFF switch.
A
discrete
3
Q
Flow rates, levels, temperatures, pressures and more are all read by a controller and the total ____ for each system may be in the hundreds.
A
variables
4
Q
a character set that contains both letters and digits is often referred to as _____
A
alphanumeric
5
Q
A device, other than a common, hand-actuated ON/OFF valve or self actuated check valve, that directly manipulates the flow of one or more fluid process streams is called a _________
A
control valve
throttling type valve
6
Q
A _____ is an output signal which represents the size of an input in the form of a series of discrete quantities.
A
digital output
7
Q
a ____ is component of a control system, such as a valve, which directly regulates the flow of energy or material to the process.
A
final control element
8
Q
a signal path where a combination of two or more instruments or control functions are arranged so that signals pass from one to another for the purpose of measurement and or control
A
loop
9
Q
process and instrumentation diagram. A drawing that uses symbols and identifiers to portray a process and the instrumentation used for monitoring and/or controlling the process and is often abbreviated by
A
P&ID
10
Q
A ______ is a device which converts information of one physical form to another physical type in its output
A
transducer
11
Q
a _____ is the part of a transducer that reacts directly in response to the input.
A
sensing element
12
Q
a conformity to an indicated, standard, or true value, usually expressed as a percentage deviation (of span, reading, or upper-range value) from the indicated, standard, or true value.
A
accuracy
13
Q
the ratio of change in output divided by the change in an input that caused it is called the _____.
A
gain
14
Q
the degree of refinement of a measurement, which depends on the sensitivity of the instrument and observation factors and is typically expressed in the smallest measurement units available.
A
precision (resolution)
15
Q
The ability of a transmitter to reproduce output readings when exactly the same measured value is applied to it consecutively, under the same conditions, and approaching from the same direction
A
repeatability
16
Q
the difference between the upper and lower limits of a transmitter range that is expressed in the same units as the range of the device
A
span
17
Q
instrument errors identified as an output signal that does not reflect 100% of the expected output signal or does not follow the input span
A
span error
18
Q
a change resulting from an error that is the same throughout the scale
A
zero shift
19
Q
accuracy is usually expressed as a percentage of the transmitter ______
A
span
20
Q
formula for calculating accuracy
A
max deviation / span X 100
21
Q
formula for calculating gain
A
output signal span / input signal span
22
Q
used to properly verify an instruments calibration
A
5 point check
23
Q
what are the five (cardinal) check points used with a 5 point check
A
0 25 50 75 100
24
Q
gauge pressure plus atmospheric pressure
A
absolute pressure ( cannot be a negative)
25
the maximum pressure applied to a transducer sensing element or case without causing leakage
burst pressure
26
the sensing element consisting of a membrane which is deformed by the pressure differential formed across it
diaphragm
27
absolute pressure minus local atmospheric pressure
gauge pressure
28
pounds per square in absolute. pressure referenced to a vacuum
PSIA
29
pounds per square in differential. pressure difference between two points
PSID
30
pounds per square in gauge. pressure referenced to standard atmosphere.
PSIG
31
the ratio pf mass of any material to the mass of the same volume of water at 4° C
specific gravity
32
any pressure less than atmospheric pressure
vacuum pressure
33
pressure is the result of a(n) ______ acting over a given ______.
force
| area
34
as fluids, when both liquids and gasses increase in _____, they also increase in ______
density
| depth/height
35
The ratio of the diameter of a pipeline constriction to the unconstricted pipe diameter
beta ratio
36
the difference in static pressure between two identical pressure taps at the same elevation located in two different locations in a primary device
differential pressure
37
flow velocity in feet per minute
fpm
38
flow velocity in feet per second
fps
39
_______ causes energy loss, due to heat dissipation when fluid is moving through a pipe.
friction
40
volumetric flow rate in gallons per hour
GPA
41
volumetic flow rate in gallons per minute
GPM
42
A field term used to describe the upstream and downstream piping, including oriface and oriface flanging
meter run
43
a flow rate in the measuring section of a flow line that does not vary significantly with time
steady flow
44
When forces due to inertia are greater than forces due to viscosity in flow line
turbulent flow
45
reynolds number
RE = p (density of fluid) x V (velocity) x D (inside diameter of pipe) / µ (viscosity in centipoise)
46
a temperature scale defined by 32 degrees at the freezing point and 212 degrees at the boiling point of water at sea level
fahrenheit
47
the process of thermal energy flowing from a body of high energy to a body of low energy
heat transfer
48
the basic unit of thermal energy
joule
49
the unit of absolute or thermodynamic temperature scale based upon the celsius scale, with one hundred units between the freezing point and the boiling point of water at sea level
Kelvin
50
An enclosure usually made out of metal at the end of a heater or probe where connections are made
protection head
51
An absolute temperature scale based upon the Fahrenheit scale with 180 degrees between the freezing point and the boiling point of water at sea level
Rankine
52
A device constructed of two dissimilar metals the generates a small voltage as a function of the difference between a measuring and reference junction
thermocouple
53
Resistance Temperature Detector
RTD
54
The cold junction is a thermocouple circuit which is held at a stable known temperature usually 0° C
reference junction
55
A closed-end tube designed to protect temperature sensors (thermocouples) from harsh environments
thermowell
56
Temperature will cause all ____, _____, and ____, to expand or contract with temperature change.
solids
gases
liquids
57
four temperature scales
fahrenheit
celcius
Kelvin
Rankine
58
when two dissimilar metals are joined at both ends and one end is heated, there is a continuous ____ which flows in the circuit.
current
59
One way to calibrate the _____ at the junction E is to place the thermocouple junction into an ice bath and force the output to be 0° Celsius or 32° fahrenheit.
voltage
60
What type of wiring, other than thermocouple wiring, is often used for thermocouple extension wiring
copper
61
seven most likely reasons for thermocouple failure or poor response
1. poor junction connection
2. recalibration of thermocouple wire
3. shunt impedance and galvanic action
4. thermal shunting
5. noise and leakage currents
6. thermocouple specifications
7. documentation
62
what is the result of altering thermocouple wiring so that it no longer performs at its rated specifications
Decalibration
63
The most common decalibration of thermocouple wiring occurs when the conductors are ____ or stressed by _____ the conductors through a conduit.
cold worked
| drawing
64
______ can degrade thermocouple insulators.
high temperature
65
______ can change the output of a thermocouple reading
galvanic action
66
_____ wiring is intended to cover long distances between the ____ and the ____
extension
thermocouple
voltmeter
67
data points should always be listed in an associated ______ sheet and care should always be taken to ensure that this data is recorded _____
specification
| accurately
68
the design of an instrument so that changes in ambient temperature do not affect readings of the instrument or compensation for ambient conditions when mounting an instrument
ambient compensation
69
a device, other than a common hand-actuated ON_OFF valve or self-actuated check valve, that directly manipulates the flow of one or more fluid process streams
control valve
70
The change through which the input to an instrument can be varied without initiating an instrument response
dead band
71
The sensing element consisting of a membrane which is deformed by the pressure differential formed across it
Diaphram
72
the component of a control system ( such as a valve) which directly regulates the flow of energy or material to the process
final control element
73
the difference between upscale and downscale results in instrument response when subjected to the same input approached
hysteresis
74
the boiling of a liquid caused by a decrease in pressure rather than by an increase in temperature
cavitation
75
a device having an output that changes to regulate a controlled variable in a specific manner
controller
76
the change of pressure will travel down the length of the pipe at approximately the speed of sound at a speed of _____
1082 ft/sec
77
the result of the ____ is the same as a nozzle flapper system to regulate the output pressure
IP converter
78
for a direct acting transducer a 4 mA signal would result in a signal pressure that is
3psi
79
a direct acting 3-15 psi I/P transducer will have the adjustment so that ____ mA would equal 3 PSI and ____ mA would correspond to 15 PSI.
4 mA
| 20 mA
80
______ systems are designed in such a way that a control valve may perform from the transducer calibrated 3-9 PSI range while another may operate from the 9-15 PSI range
split range
81
A standard reverse-acting transducer when calibrated correctly will have an output of ____ PSI when 4 mA is applied and an output of _____ PSI when 20 mA is applied.
15 PSI
| 3 PSI
82
to "bench set" a valve, the valve body must be _____ from the actuator to set actuator stem movement given specific applied pressures
decoupled
83
a(N) ______ is a mechanical device which can be used to determine the physical position of equipment
limit switch
84
are constructed of flexible ferrous strips and are placed near the intended travel of the valve stem or control rod extension. Using a permanent magnet as an extension, as the magnet approaches, the switch shuts.
reed switches
85
Moving the extension rings between the primary and secondary windings of a transformer causes the inductance between the two windings to vary, thereby varying the output voltage proportional to the position of the valve or control rod extension. This is a function of _____
L inear
V ariable
D ifferential
T ransformer
86
A control valve with a direct - action actuator and direct trim will fail ____
open
87
If the pressure drop across a valve increases, then the flow velocity of the liquid through the valve must ____
increase
88
In most process control systems, the final control element is a _____
control valve
89
control valves which have a plug positioned by a stem which slides through a packing gland are often called ____ control valves
sliding stem / globe valve
90
The acronym for binary digit. The smallest unit of computer information, it is binary 0 or 1
BIT
91
An eight-bit representation of binary character
Byte
92
The portion of a computer that decodes the instructions, performs the actual computations, and keeps order in the execution of programs
CPU
93
The storage device in which programs and data are stored and easily obtained by the CPU for execution
memory
94
A 3-mode control action where the controller has time-proportioning, integral (auto reset), and derivative rate action
Proportional
Intergral
Derivitive
95
The analog signal can typically be read in as a ____ or _____ voltage or current range.
4-20 mA
| 1-5 Vdc
96
RAM
random access memory
temporary - can be rewritten
97
ROM
Read Only Memory
Permanent and cannot be changed
98
An ESD system is a stand alone _____ that receives inputs from field _____, _____ control actions, valve positions, and more, but does not have process variables that can be changed by ______ interaction.
controller
instruments
DCS
human
99
A control system that is eaters on or off, or a control system that is either on or off, this two-position control is called a _____ control
discrete
100
The action in which the controllers output is proportional to the time integral of the error input, and when used in combination with proportional control, it is commonly called rest action but is defined as _____ action
integral control
101
a 3-mode control action where the controller has time-proportioning, integral(auto reset), and derivative rate action is denoted by the abbreviation
PID
102
The reciprocal of gain expressed as a percentage, which refers to the percentage of the controllers span of measurement over which the full travel of the control valve occurs
proportional band
103
control action in which there is a fixed gain or attenuation between output and input
proportional control
104
the proportion of controller output that is proportional to the rate of change of input
rate / derivative
105
describe feedback as it is used in a control loop
feedback confirms if change works
106
the ability of a process to withstand change in the process variable.
capacitance
107
describe transfer lag
the time it takes for a process to recover from a change
108
two position control
on/off
| discrete
109
a character set that contains both letters and digits
alphanumeric
110
a device or circuit that outputs a binary number corresponding to an analog signal level at the input
analog to digital
111
a term applied to a signal or device which uses binary digits to represent continuous values or discrete states
digital
112
the sequence of letters or digits or both used to designate an individual instrument or loop
identification code of the loop
113
a formal definition that describes how data is to exchanged
protocol
114
the collection of programs and routines associated with a computer
software
115
a smart communicator is used to provide a working ____ to a smart device
interface
116
A term applied to a device or system whose functional characteristics can be selected or rearranged through programming or other methods
configurable
117
the elements in a control system that contribute to the required corrective action
controlling means
118
memory that can be erased by ultraviolet light or electricity
```
E rasable
P rogramable
R ead
O nly
M emory
```
119
A semiconductor whose contents cannot be changed by the computer after it has been programmed
P rogrammable
R ead
O nly
M emory
120
an alphanumeric sequence which identifies a device by assigning a unique identifier
tag number
121
if a smart transmitter is selected to "fail Low" then when an unrecoverable error is detected by the electronics the transmitter will output a signal that is relatively ____ than zero (4 mA)
less
122
a loop test can be performed to verify the ____ of a transmitter
output
123
before any configuration, sending, or requesting data from a smart instrument with a communicator it is good practice to place the loop in ____
manual more
124
the conformity to an indicated standard or true value usually expressed as a percentage deviation (of span reading or upper range value) from the indicated standard or true value is referred to as the _______ of the device
accuracy
125
The departure from a desired value. The system deviation that exists after the process has been stabalized
deviation
126
process and instrumentation diagrams
P & ID
127
The ability of an instrument to provide the same output signal given the identical input
repeatability (precision)
128
The specified pressure which may be applied to the sensing element of a transducer without causing a permanent change in the output characteristics
proof - pressure
129
The length of time it takes a transducer to return to normal after a proof - pressure has been applied
recover time
130
the boiling of a liquid caused by a decrease in pressure rather than an increase in temperature
cavitation
131
a device other than a common hand-actuated ON-OFF valve or self-actuated check valve that directly manipulates the flow of one or more fluid process streams
control valve
132
the sensing element consisting of a membrane which is deformed by the differential pressure formed across it
diaphragm
133
the component of a control system (such as a valve) which directly regulates the flow of energy or material to the process.
final control element
134
the difference between upscale and downscale results in instrument response when subjected to the same input approached from opposite directions
hysteresis
135
the delay in output change following a change in input applied to an instrument or control system
lag
136
is a device which converts information of one physical form to another physical type in its output
transducer
137
what type of device is used to verify and/or force a valve to known position
valve positioner
138
pneumatic valve actuator is one of which two types
diaphragm
| piston
139
the direct acting actuator has its spring set to ____ the inlet pressure that opposes the valve
oppose
140
the reverse acting actuator has its tension set to ______ a valve back to its original position
move
141
A valve transduver (I/P) converts a(n) ____ to _______
current
| pneumatic pressure
142
What are the most common calibration ranges that I/Ps are calibrated for
4-20 mA
| 3-15 PSI
143
cage type valves generally work at ______ operating pressures and allow for an even alignment throughout the range of the stroke
higher
144
A rotary valve is style of valve that uses a ______ turn of the valve stem to position a valve closure member
quarter
145
PH is a unit of measurement which determines the degree of acidity or alkalinity of a solution and is measures on a scale of
0 - 14
146
If a solution has a PH measures value of 4 it is said to be _____
acidic
147
If a solution has a PH measures value of 10 it is said to be _____
base / alkaline
148
The alkali metal ions and the hydrogen ions in the process sample create an exchange reaction between the dissimilar ions which creates a potential difference measured in _____ which is then converted to a ______ used by a controller.
millivolts
| signal
149
A _______ solution has a constant PH value and has the ability to resist changes in PH levels.
Buffer
150
Care should be taken when handling an electrode. ______ should be worn and the glass portion of the electrode should not _____ contaminated surfaces, especially your unprotected hands.
gloves
| contact
151
a PH reading of seven is referred to as a _____ solution and may be compared to pure distilled water
neutral
152
As with all calibrations, there must be a standard in which the measured variable can be compared. Some of the solutions that may be used for comparison have PH values of ____ ____ ____.
4 , 7 , 10
153
Electrodes should be ______ between samples with distilled or de-ionized water.
rinsed
154
most facilities require a _____ point check of the analyzers readings
three
155
the millivolt output of PH electrodes varies with temperature and the magnitude of the variation is directly dependent upon the _____ and the PH value of the solution being measured
temperature change
156
The difference between the actual and the true values, often expressed as a percentage of the span or upper range value
error
157
An instrument which does not produce any spark or thermal effects under normal or abnormal conditions that will not ignite a specified gas mixture
intrinsically safe
158
An optical illusion which occurs in analog meters and causes reading errors. it occurs when the viewing eye is not in the same plane, perpendicular to the meter face, as the indication needle is called a ______ error
parallax
159
Lowering the output caused by an additional or unwanted pressure on the high side of a DP cell. The term is normally used for a condition that has the 4 mA output high when there is a 0% level. When performed this process is called _____
suppression
160
Change resulting from an error that is the same throughout the scale of calibration
zero - shift
161
the electronics housing may be rotated no more than ____ degrees when mounting
90
| 360 - new units
162
When mounting a transmitter that is to measure liquids the vent valves should be mounted ______ the impulse tubing to allow gases to
above
| vent
163
when mounting a transmitter that is to measure gases the vent valves should be mounted ______ the impulse tubing to allow liquids to
below
| drain
164
for gas measurement you want to mount the transmitter so that the taps are to the ______ of the process lines
side / top
165
for steam measurement, you want to mount the transmitter so that the taps are to the ______ of the process lines
to the side. below the taps
166
When mounting a transmitter that is to measure steam, the impulse tubing lines are to be filled with ______ to prevent the steam from coming into contact with the transmitter sensor.
water
167
_______ and _______ are two conditions that an installer must always consider when measuring liquids.
elevation
| suppression
168
Impulse tubing carries the signal from the ______ to the ________
process
| transmitter
169
Impulse tubing should be routed ______ from the transmitter to the process for LIQUID measurement
upward
170
Impulse tubing should be routed ______ from the transmitter to the process for GAS measurement
downward
171
When the signal current is to be measured without using the test terminals an ammeter must be placed in ______ with the loop wiring
voltages
| noise
172
The shield that is found around twisted pair conductors is generally grounded on the ______ end to negate ______ effects and magnetic effects
source
| capacitive
173
If the sensor is an RTD, _____ or RTD simulator would be connected to the transmitter input in place of the RTD.
decade box
174
angularity adjustments are used for
pneumatic controllers
175
working height of ladder is
length - overlap
176
what is shutdown procedure for 3 valve manifold
close hi side
open equalize valve
close lo side
177
reynolds number
velocity / viscosity low number means high viscosity or large pipe.
178
three common types of positive displacement flow meters
piston
oval gear
nutating disc
179
where are flange taps when used with oriface plates
1' upstream
| 1" downstream
180
flowmeters must be properly _______ to work properly.
grounded and bonded
181
oriface plates are selected to give a pressure drop of about _____ at the operating flow rate
100" H20
182
most/least common oriface plates
paddle concentric bore - least
| universal concentric bore - most
183
type TC oriface plate
paddle conical entrance
not common only used for low flow applications
184
type TE oriface plate
paddle eccentric bore
2nd most common used when slurry or sediment is present
185
type TS oriface plate
Paddle segmental bore
3rd most common
186
1 ft H20
.4333
187
1 PSI
27. 7 in H20
| 2. 036 in HG
188
1 cu ft H20
62. 43 lbs
| 7. 48 gals
189
gal h20
8.33 lbs
