- In process control the desired value of a system is referred to as the__________?
- In process control, the term the “process”, whatever it may be, may also be referred to as the ______________.
- The device that exerts a direct influence on the process is called the _____________.
- Control system objectives should include:
- The response criterion that specifies that the amplitude of each peak of each cyclic response be a quarter of the preceding peak is called_________.
- The mathematical relationship between the input of a block and the output of that block is known as the __________ __________.
- The equation below describes the response of a __________________ order system.
8. The current through a RTD can cause the RTD to heat up. This factor is accounted for by use of the ____________________.
- Type J, T, K, E, S, and R are all thermocouple types. The letter designates_______________.
- Since Thermocouple voltages are small, great care should be taken to protect against electrical noise by_________________.
- Strain gauges operate based on the change in ___________________ of a metal under stress.
- The primary form of ____________ sensor is the accelerometer.
- Flow across an orifice plate varies proportionally with the ___________ of the differential pressure.
- A rotameter, a moving vane flow meter and a turbine flow meter all place ________________ in the flow of the material.
- Elements of final control are:_______________.
- A _________________ is required to condition the signal from a computer so that it might interact with process control equipment.
- A simple device that can convert mechanical motion to pneumatic pressure levels is the __________________.
- Control valve sizing is done by choosing the valve size with the appropriate ___________________.
- A process that can be controlled by reading on or off conditions and responding with other on or off conditions is called a _____________ state system.
- Alarm conditions can best be described by_________________________.
- Programmable logic controllers can replace electromagnetic relays in control systems.
- The below schematic symbol is a _________________.
23. Could the below circuit be used to control a motor starter?
24. The process the PLC uses to read the inputs, solve the ladder logic, and drive the outputs is the PLC_____________ for that specific application.
- In order for the PLC to interact with the process inputs and outputs the I?O must be compatible with the input signal and output signal __________.
- Sensor resistance varies from 25 to 1.5 kΩ as a variable changes from cminto cmax. Design a signal-conditioning system that provides an output varying from –2 to +2 V as the variable changes from min to max. Power dissipation in the sensor must be kept below 2.5 mW.
The circuit could be implemented as under:
- A 10-bit unipolar ADC with a reference of 5.00 F and a 44-μs conversion time will be used to collect data on time constant measurement. Thus, the input will be of the form V (t) = 4(1− et/τ ) . What is the minimum value of τ for which reliable data samples can be taken if no Sample-and-Hold circuit is used?
- A type K thermocouple with a 0°C reference will be used to measure temperature between 200°C and 350°C . Devise a system that will convert this temperature range into an 8-bit digital word with conversion from 00H to 01H at 200°C and from FEH to FFH at 350°C . An ADC is available with a 2.500-V internal reference. At 200°C a type K TC produces 8.13 mV. At 350 °C a type K TC produces 14.29 mV.
- A strain gauge has a GF=2.14 and a nominal resistance of 120 Ω . Calculate the resistance change resulting from a strain of 144μin / in .
- Consider the phototransistor with IV curves below left and used in the circuit below right. Calculate the output voltage when the light intensity is equal to 20 W /m2.
- A 4- to 20-mA control signal is loaded by a 100-Ω resistor and must produce a 20- to 40-V motor drive signal. Develop the equation relating the input current to the output voltage. Implement the equation if a power amplifier is available that can output 0 to 100V and has a gain of 10.