1. Compared with resistance thermometers, thermocouple thermometers can measure higher temperatures. ( √ )
2. The pressure measuring element of the spring tube manometer can be a circular spring tube with uniform wall thickness. ( × )
3. The float level gauge belongs to the constant buoyancy level gauge, and the float level gauge belongs to the variable buoyancy level gauge. ( × )
4. The smaller the time constant of the control channel, the shorter the time for the object to reach a stable value after being disturbed. (√ )
5. In the chemical process, the time constant and lag time of the temperature control object are usually short. ( × )
6. Cascade regulation system can be used to improve the objects with long pure lag time, which has the leading role. ( √ )
7. Feedforward control is controlled according to interference. If the control is just right, it is generally more timely than feedback control. ( √ )
8. Regulating valve can be divided into pneumatic, hydraulic and electric according to power source. According to the action form of the valve core, it is divided into straight stroke and angular stroke. (× )
9. In the flow formula of differential pressure flowmeter, the flow is directly proportional to the differential pressure. ( × )
10. The error caused by improper installation position of the instrument belongs to negligence error. ( × )
Second, multiple-choice questions (10)
1. The secondary instrument refers to the measuring instrument (C) in the structural composition.
A sensing element b connecting element c display element
2. The standard nozzle pressure method is (c).
A flange pressure, B angle pressure and C angle pressure or flange pressure.
3. An electronic potentiometer is used to measure the signal (b).
A resistance b millivolt potential c force
4. To measure the furnace temperature around+1000℃, the thermometer (A) should be selected.
A Ni-Cr-Ni-Si thermocouple B platinum resistance C copper resistance
5. The weighing level gauge is designed according to principle (A).
A balance b energy balance c voltage balance
6. In order to ensure the safe operation of the equipment, it is necessary to choose (B) as the air-opened regulating valve.
A boiler drum water supply control system B boiler fuel (gas) control system
C boiler furnace inlet induced air pressure regulating system
7. The most unfavorable interference to the regulating system is (c).
A random interference b sine wave interference c step interference
8. The split-range control system belongs to (a) control system.
Single-loop B-stage C feedforward
9. The servo control system is also called (b) control system.
A fixed value b automatic tracking c program
10. (3) The control law has the function of guiding control.
Proportional integral differential