1, the centralized control system is generally composed of (process input and output interface unit), (process control unit), (CRT operator station), (high-speed data path).
2, commonly used flexible pressure gauge: (diaphragm type), (bellows type) and (spring tube type).
3, pneumatic piston actuator is divided into (proportional), (two-position type).
4, according to the law of error, error can be divided into (systematic error), (random error), (negligence error).
5, hydrostatic level meter is based on the fluid (hydrostatic) balance principle, it can be divided into (pressure) type and (differential pressure) type two categories.
6, temperature is a measure of (material hot and cold) a physical quantity, temperature can not be measured directly, only through other objects (with the temperature change) of the physical quantity to be measured indirectly.
7, complex control systems are (series control system), (divided control system), (ratio control system), (feed-forward control system), (selective control system) and so on.
8, regulating low pressure difference and large flow gas can be used (butterfly) valve, regulating strong corrosive fluids can be used (diaphragm) valve, noise is very large can be used (sleeve) valve.
9, explosive gas mixture explosion must have the conditions: (a certain concentration) and (enough spark energy).
10, in the RTD thermometer, R0 and R100 respectively (0 ℃) and (100 ℃) when the resistance value.
11, the regulated medium flows through the valve relative flow (Q/Qmax) and the valve relative stroke (l/L) of the relationship between the valve is called the regulating valve (flow characteristics).
12. Low-voltage appliances can be divided into (manual low-voltage appliances) and (automatic low-voltage appliances).
13. Electromagnetic appliances from the structural point of view, mainly consists of two parts, one for the (detection part or electromagnetic mechanism), and the second for the (executive part or contact system).
14. AC contactor is mainly composed of four major parts, namely (electromagnetic mechanism), (contact system), arc extinguishing device, and other auxiliary components.
15. (Current) transformer secondary grounding belongs to the protective grounding, to prevent the primary insulation breakdown, so that the secondary into the high voltage, threatening personal safety, damage (equipment).
16. three-phase electromotive force or current amplitude of the order of appearance for the phase sequence, phase sequence for A-B-C, usually called (positive sequence or order); phase sequence for C-B-A, usually called (negative sequence or reverse order).
II. Judgment
1, the choice of thermocouple temperature measurement, if the connection wire with compensation wire, you can not consider the cold end of the thermocouple compensation (×)
2, in the hazardous location and control room set up between the safety grid, so that the system is called a safe spark-type explosion-proof system (×)
3, rotor flowmeter upstream side of the straight pipe is not strict requirements, but its conical tube must be installed vertically, not tilted. Installation, can not be tilted. ( √ )
4, electromagnetic flowmeter is not able to measure the flow of gaseous media (√ )
5, flange transmitter zero adjustment and zero positive and negative migration is the same thing, just called a different (×)
6, when measuring the level of the open container with a single-flange transmitter, the transmitter should be adjusted to the zero of the positive migration. (×)
7, the installation of elliptical gear flowmeter can be installed without the need for straight pipe section (√)
8, electromagnetic flow transmitter and chemical piping fastened together, can no longer need to ground wire. (×)
9, copper RTD temperature measurement range than platinum RTD temperature measurement range is wide. (×)
10, in the same temperature change range, the index number Pt100 RTD than Pt10 RTD change range, thus higher sensitivity. (√ )
11. Fluid flowing in a unit of time expressed in terms of volume is called volumetric flow rate (√ )
12. Absolute error is the algebraic difference between the true value and the measured value (√ )
13. An electrical circuit generally consists of a power supply, a load, a wire, and a switch (√ )
14. If the resistance between two points of an electrical circuit is infinite, then the points are called Open circuit (√ )
15. All kinds of electrical equipment operating at rated condition is called full load (√ )
16. When it operates beyond its rated value, it is called overload (√ )
III. Choice
1, the installation of the orifice plate on the pipe, if the direction of the reverse will cause (C )
A Differential Pressure Gauge inverted indication B Differential Pressure Gauge becomes larger C Differential Pressure Gauge indication becomes smaller
2, rotor flow meter in the direction of the flow of fluid is ( B )
A from top to bottom B from bottom to top C top to bottom and bottom to top both can be
3, by pressure method Measurement of open container level, the level depends on (B)
A pressure point location and container cross-section B pressure point location and media density
C media density and cross-section
4, rotor flowmeter in the rotor above and below the pressure difference is determined by (C).
A the velocity of the fluid B the pressure of the fluid C the weight of the rotor D the structure of the rotor
5, turbine flow transmitter should be (B) installed.
A vertical B horizontal C tilted 45 degrees D random installation
6, a turbine flowmeter and a vortex flowmeter are calibrated with water at room temperature. When they are used to measure the volume flow rate of liquid ammonia, (B)
A both need to be corrected for viscosity and density
B the turbine flowmeter needs to be corrected for viscosity and density, the vortex flowmeter does not need to be corrected for viscosity, the vortex flowmeter does not need to be corrected for viscosity
7, which of the following elements is not a throttling element (D)
A Orifice plate p>
A Orifice B Venturi C Nozzle D Impeller E Doyle tube
8, different measuring range of 1151 differential pressure transmitter is due to the measurement of the diaphragm of (A)
A thickness is different B material is different C diameter is different
9, if the use of the pressure gauge range is lower than 1/3 of its range is (C)
A due to the pressure is too low instrument did not Indication B accuracy level decreased C relative error increased
10, regulating valve packing at high temperatures (+450 ~ +600 ℃), can not be used (A)
A tetrafluoro packing B graphite packing
11. Response to the resistance element of the relationship between the voltage on both sides and the current, resistance of the three laws are (C).
A: Kirchhoff B: Joule's law C: Ohm's law D: Law of full circuits
12. To extend the range of an ammeter, you should (B).
A: series resistance B: parallel resistance C: mixed resistance D: series capacitance
13. When a symmetrical three-phase power supply is connected in a star pattern, the line current is equal to (A).
A: phase current B: multiples of phase current C: rated capacity divided by rated voltage D: 2 times phase current
IV. Questions and Answers
1, which parts of the regulator valve maintenance should focus on checking?
2, a brief description of the EJA (silicon resonance type) intelligent transmitter working principle?
4, a brief description of the working principle of the rotor flow meter.
5, compared with conventional analog instrumentation, decentralized control system (DCS) has what advantages?
.6. What are the characteristics of pneumatic piston actuators?
Instrumentation Training Second Test Questions
I. Fill in the blanks (1 point per blank, ***30 points)
1, according to the method of expression of the value of the error (absolute error), (relative error), (quoted error).
2, thermocouple thermal potential conditions are (two heat pole material difference), (two node temperature difference).
3, regulating valve is composed of (valve body parts) and (actuator).
4, the maximum flow rate controlled by the control valve and the minimum flow rate of the control valve is called (adjustable ratio), expressed in R. The valve can be used to control the flow rate of the control valve.
5, a simple control system is composed of (controller), (actuator), (the empty object), (measuring transmitter).
6, commonly used throttling elements are (orifice plate), (nozzle), (venturi)
7, throttling orifice plate before the general requirements of the straight pipeline (10)D, orifice plate after the best straight pipeline (5)D. In order to correctly measure the orifice plate in front of the straight pipeline is best for the (30-50)D, especially in front of the orifice plate with pumps or regulating valves, it should be more so.
8, distributed control system generally by (process input and output interface unit), (process control unit), (CRT operator station), (high-speed data pathway is composed of).
9, commonly used flexible pressure gauge: (diaphragm type), (bellows type) and (spring tube type).
10, the transmitter is composed of (measuring part), (amplifier), (feedback part).
11, pneumatic thin-film actuators are divided into the form of (positive), (reaction).
II. Judgment (2 points per question, ***20 points)
1, when measuring the corrosion of conductive and with solid trace, and the choice of electromagnetic flowmeter (√)
2, elected to use thermocouples to measure the temperature, if the connecting wires to use the compensating wires, you can not take into account the thermocouple's cold-end compensation (×)
3, in the hazardous area and the control room set up between the safety fence, so that the system called the safety spark-type protection. The system is called a safe spark type explosion-proof system (×)
4, string control system is a simple control system (×)
5, rotor flowmeter upstream side of the straight pipe requirements are not strict, but it must be installed vertically tapered tube, can not be tilted. ( √ )
6, electromagnetic flowmeter is not able to measure the flow of gaseous media (√ )
7, as the fluid may be mixed with impurities, so in order to protect the flowmeter must be equipped with filters (√ )
8, flange transmitter zero positive migration refers to the input of the positive pressure when the zero point of the adjustment (√ )
9, the corner of the take-off and flange take-off just take-off of pressure (√ )
9, angle take-off and flange take-off is just a The way is different, but the body structure of the standard orifice plate is the same. (Right)
10, a pneumatic thin-film control valve, if the valve stem in 50% of the full stroke position, the flow rate through the valve is also 50% of the maximum amount. (Wrong)
III. Select (2 points per question, ***20 points)
1, the accuracy level of the instrument refers to the instrument (D)
A error B basic error C maximum error D the maximum allowable value of the basic error
2, the pressure of a container for 1MPa, in order to measure it should be used for the range of (D) pressure gauge
A.0-1MPa B -0.1- 1MPa C 0-4MPa D 0-2.5MPa
3, the polarity of the 1151 transmitter is reversed, then the instrument (C )
A maximum output B burned out C no output D minimum output
4, the installation of orifice plate in the pipe, if the direction of the reverse direction will result in (C )
A Differential Pressure Gauge inverted indication B Differential Pressure Gauge becomes larger C differential pressure gauge indication Smaller
5, pure feed-forward regulation is a kind of control system can be compensated for ( C )
A measurement and the deviation between the given B the change of the controlled variable C the change of the interference
6, the rotor flowmeter must be ( A ) installed
A vertical B horizontal C down
7, rotor flowmeter in the direction of the flow of fluid ( B )
7, rotor flowmeter B )
A top-down B bottom-up C top-down and bottom-up can be
8, with a throttle device to measure the volume flow of wet gas, if the relative humidity of the working state
degree than the design increased, then the meter value will be (A )
A greater than the true value B equal to the true value C less than the true value
9, with the Pressure method to measure the level of open containers, the level depends on (B)
A pressure point location and container cross-section B pressure point location and medium density
C medium density and cross-section
10, the following about the resistance thermometer in the narrative, which narrative is not appropriate. (D)
A Resistance thermometers work by utilizing the fact that the resistance of a resistance wire changes linearly with temperature.
B Resistance thermometers are characterized by a time delay in temperature detection.
C Thermocouple thermometers are capable of higher temperatures than resistance thermometers.
D Because the resistance wire of the resistor body is made of thicker wire, it is more resistant to vibration.
E temperature measurement resistor body and thermocouple are inserted into the protection tube to use, so the construction of the protection tube, materials, etc. must be carefully selected.
IV. Question and answer (6 points per question, ***30 points)
1, the regulator valve is divided into several parts? Which parts? What is the role of each?
Answer: two parts, respectively, for the actuator and valve body parts.
The actuator is the driving device of the control valve, it produces the corresponding thrust according to the size of the signal, so that the push rod produces the corresponding displacement, thus driving the spool action of the control valve.
The valve body is the regulating part of the regulating valve, it is directly in contact with the medium, the action of the spool to change the valve's cut-off area, so as to achieve the regulating effect.
2, what is the role of the safety grid?
Answer: the safety grid is to ensure that the process control system has a safe spark explosion-proof performance of the instrument, which on the one hand, the role of signal transmission, on the other hand, it is also used to limit the flow of energy into the hazardous areas.
3, briefly describe the entire process flow of the project you are trained. (From the beginning to the finished product)
4, briefly describe the working principle of electromagnetic flow meter.
5, compared with conventional analog instrumentation, decentralized control system (DCS) has what advantages?
Select
1 The differential pressure above and below the rotor in a rotor flow meter is determined by (C).
A velocity of the fluid B pressure of the fluid C weight of the rotor D structure of the rotor
2 The rotor flow meter must be ( A ) installed
A vertical B horizontal C down
3 When installing the orifice plate on the pipe, if the direction is reversed, it will cause ( B)
A the differential pressure gauge inverted B the differential pressure gauge indication becomes smaller C the differential pressure gauge indication becomes larger D the differential pressure gauge indication is not affected. No effect on the differential pressure gauge indication
4 If the use range of the pressure gauge is less than 1/3 of its range, then (C)
A because the pressure is too low instrument does not indicate B the accuracy of the level of decline in the C relative error increases
5 flange transmitter response time is longer than the ordinary transmitter, in order to shorten the flange transmitter transmission time should be AC
A the capillary as short as possible B the capillary as long as possible B capillary as long as possible C capillary diameter as small as possible D capillary diameter should be larger
Fill in the blanks
1 Absolute error is the difference between the (measurement result) and (true value).
2 According to the method of expression of the error value (absolute error), (relative error), (quoted error).
3 According to the law of error (systematic error), (random error), (negligence error).
4 Thermocouple thermal potential conditions are (two heat pole material difference), (two node temperature difference), with the composition of the thermocouple (material and temperature of the two ends), with the thermocouple wire (thickness and length) has nothing to do.
5 Regulating corrosive fluids should usually use (diaphragm valve).
6 Differential pressure before and after the regulating valve is small, the requirement of small leakage, generally can choose (single-seat valve).
7 DCS is the full name of the English (Distributed), (control), (system)
8 computer software (system software) and (application software) two major parts.
9 The centralized control system generally consists of (process input/output interface unit), (process control unit), (CRT operator station), (high-speed data path).
10 commonly used flexible pressure gauge: (diaphragm type), (bellows type) and (spring tube type).
Judgment
1 When measuring the corrosion of conductive and with solid trace, and the choice of electromagnetic flowmeter (√)
2 When the choice of thermocouple temperature measurement, if the connecting wires to use the compensation of the wire, you can not take into account the thermocouple's cold-end compensation (×)
3 In the hazardous area and the control room set up a safety fence, so that the composition of the system is called the safety of the type of sparks Explosion-proof system (×)
4 Serial control system is a simple control system (×)
5 As the fluid may be mixed with impurities, so in order to protect the flow meter must be fitted with a filter (√ )
Short Answer
1. What are the characteristics of pneumatic valves?
Answer: simple structure, easy to operate, reliable operation, easy maintenance, through the electrical conversion valve positioner and computer and regulator compatible with fire and explosion-proof function.
2. How many parts of the control valve? Which parts? What is the role of each?
Answer: two parts, respectively, for the actuator and valve body parts.
The actuator is the valve's driving device, which according to the size of the signal to produce the corresponding thrust, so that the push rod to produce the corresponding displacement, thus driving the spool action of the valve.
The valve body is the regulating part of the regulating valve, it is directly in contact with the media, the action of the spool to change the valve's cut-off area, so as to achieve the regulating effect.
3. What is the role of the safety grid?
Answer: The safety grid is to ensure that the process control system has a safe spark explosion-proof performance of the instrument, which on the one hand, the role of signal transmission, on the other hand, it is also used to limit the flow of energy into the hazardous area
4. What is cavitation?
Answer: due to flash and cavitation caused by the spool and seat and valve body material damage phenomenon.
5. The main advantages of sleeve control valve?
Answer: (1) good stability; (2) interchangeability and versatility; (3) the use of differential pressure, thermal expansion effect is small; (4) easy maintenance; (5) long service life; (6) low noise.
6. How to choose the pneumatic control valve air open and air closed type?
Answer: Selection of the above two forms of pneumatic control valve, to be considered from the following aspects.
(1) accident conditions, the process device should try to be in a safe state;
(2) accident conditions, to reduce the consumption of raw materials or power, product quality;
(3) Consider the characteristics of the medium. Such as the medium is easy to crystallize, easy to solidify.
Instrumentation Specialty Test Questions
I. Fill in the blanks (1 point per blank, ***30 points)
1, throttling orifice plate before the general requirements of the straight pipeline ( )D, after the orifice plate of the straight pipeline preferably ( )D. In order to correctly measure the orifice plate before the straight pipeline preferably ( )D, especially when the orifice plate before the pumps or regulating valves, it should be more so.
2, commonly used elastic pressure gauge: ( ), ( ) and ( ).
3, the thermoelectric properties of thermocouples by the electrode material ( ) and ( ) is determined by the size of the thermal potential and ( ) and ( ) related to the thermocouple wire ( ) and ( ) has nothing to do.
4, in the pressure gauge model of the first letter Y said ( ), Z said ( ), YZ said ( ), followed by the number of ( ), solid model YZ-100 refers to ( ).
5, the choice of regulating valve packing, high temperature should be selected ( ), room temperature selection ( ), which ( ) friction.
6, in order to ensure that the connection of the pressure gauge is tight, the installation should be based on the characteristics of the measured pressure and the medium with appropriate gaskets, the measurement of oxygen pressure shall not be used ( ) gaskets, ( ) gaskets, measurement of acetylene pressure shall not be used ( ) gaskets.
7, instrumentation routine maintenance work is broadly divided into ( ), ( ), ( ), ( ) ( ).
8, the valve positioner is generally divided into ( ), ( ) two categories.
II. Judgment (2 points per question, ***20 points)
1, when measuring the corrosion of conductive and with solid trace, it is appropriate to use electromagnetic flowmeter ( )
2, in the hazardous area and the control room set up between the safety grid, so that the system is called a safe spark-type explosion-proof system ( )
3, rotor flowmeter upstream side of the straight pipe is not strict, but its cone must be installed vertically It can not be tilted. ( )
4, electromagnetic flowmeter is not able to measure the flow of gas media ( )
5, flange transmitter zero positive migration refers to the input for the positive pressure when the zero adjustment ( )
6, angle pickup and flange pickup pressure is only a different way to pick up the pressure, but the standard orifice plate of the body structure is the same. ( )
7, a pneumatic thin-film control valve, if the valve stem in 50% of the full stroke position, the flow through the valve is also 50% of the maximum amount of flow. ( )
8, flange transmitter zero adjustment and zero positive, negative migration is the same thing, just called different. ( )
9, when using a single flange transmitter to measure the level of open container, the transmitter should be zero positive migration adjustment. ( )
10, electromagnetic flow transmitter and chemical piping fastened together, can not be grounded. ( )
Three. Select (2 points per question, ***20 points)
1, the accuracy level of the instrument refers to the instrument ( )
A error B basic error C maximum error D basic error of the maximum allowable value
2, the pressure of a container for 1MPa, in order to measure it should be used for the range of ( )pressure gauge
A.0-1MPa B -0.1- 1MPa C 0-4MPa D 0-2.5MPa
3, the installation of the orifice plate on the pipe, if the direction of the reverse will result in ( )
A Differential pressure gauge inverted indication B Differential pressure gauge to become larger C Differential pressure gauge indication to become smaller
4, pure feed-forward regulation is a control system can be compensated for ( )
A Deviation between the measurement and given B Changes in the controlled variable C Interference amount The change of the variable C the change of the interference quantity
5, rotor flowmeter must be ( ) installation
A vertical B horizontal C down
6, rotor flowmeter in the direction of fluid flow is ( )
A from top to bottom B bottom to top C top to bottom and bottom to top can be
7, with the pressure method of measurement of the level of open container, the level of liquid High and low depends on ()
A pressure point location and container cross-section B pressure point location and media density
C media density and cross-section
8, rotor flowmeter rotor up and down the pressure difference is determined by ( ).
A fluid speed B fluid pressure C rotor weight D rotor structure
9, turbine flow transmitter should be ( ) installation.
A vertical B horizontal C tilted 45 degrees D random installation
10, with the pressure method to measure the level of the open container, the level depends on ( )
A pressure point location and container cross-section B pressure point location and media density
C media density and cross-section
Four. Questions and Answers (6 points per question, ***30 points)
1. How many parts are there in a control valve? Which parts respectively? What is the role of each?
2, what is the role of the safety grid?
3, briefly explain the working principle of electromagnetic flowmeter.
4, a brief description of the basic content of the instrumentation workers tour inspection.
5, a brief description of the regulating valve (with electrical valve positioner) on-site validation steps, and draw a schematic diagram.