Tag: Industrial control
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RTD 2, 3, 4 Wire Sensor Connections
The resistance temperature devices (RTD) can be connected directly to the controller peripheral amplifiers using 2-wire, 3-wire or 4-wire lead configuration. The wires in all these connections are in shielded cables. The RTD is usually driven from a constant current … Read more
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How to Connect a DP (Differential Pressure) Flow Sensor to a DP Transmitter
The DP Transmitter should be mounted with a manifold block as illustrated in the figure 1(a) below to allow for maintenance. Figure 1(a) connection of a DP flow sensor to a DP transmitter Valves B and C are the isolation … Read more
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Instrumentation Sensors and Transducers – Multiple Choice Questions & Answers (MCQ4)
The Answers have been provided at the end of the Questions: Q1. Which of the following sensors is used to measure displacement? A. Thermistor B. LVDT C. Dall tube D. None of the above Q2. Which of the below … Read more
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How Signal Processing Circuits are protected from high currents & voltages
Protection against high currents and voltages is a very important requirement for signal processing circuits. A high current can be protected against by the incorporation in the input line of a series resistor to limit the amount of current flowing … Read more
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How RS-232, RS-422 and RS-485 Networks are applied in Instrumentation
RS-232 Presently, this standard is known as TIA-232C. These are point-to-point networks with a purpose of connecting only two devices. The signaling is single-ended (unbalanced) which implies that the respective voltage pulses are referenced to a common ground conductor and … Read more
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Basic Features of Foundation Fieldbus (FF)
Foundation fieldbus (FF) and Profibus are the two most universal serial data bus formats that are used for interfacing between the central processor and smart devices in the process control system. The Foundation Fieldbus is mainly used in U.S. while … Read more
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Features of Stepper Motors & How they are applied in Industrial Control
A stepper motor is a permanent magnet or variable reluctance DC motor that has the following characteristics: It is able to rotate in both directionsIt can move in precise angular incrementsIt can sustain holding torque at zero speed… Read more
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How Servo Motors are used in Process Control
Servo motors are continuous motion mechanisms that use feedback signals to provide position and velocity control in a closed loop system. Servo motors can rotate to a given position be stopped and reversed. The angular position and speed can … Read more
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How to Tune the PID Controller
Before we discuss how to tune the PID controller, let’s look at some basic facts about PID Controller. Basic Facts about PID Controller Many control systems use a combinational of three types of control i.e. Proportional + Integral + Derivative … Read more
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4-20 mA Transmitters (2-wire, 3-wire and 4-wire Types)
Background of 4-20 mA Signal Transmission Initially signal transmission was dominated by pneumatics before the advent of 4-20 mA signal standard. The standard was 3-15 psi pneumatic signal where the 3 psi was the ‘live zero’ and 15 psi represented … Read more