Tag: instrumentation
-
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 the 100 %. Any pressure below 3 psi was considered ‘dead zero’ and an alarm…
-
What is a Smart Sensor?
A smart sensor is the integration of a sensor with an analogue to digital converter (ADC), a processor and digital to analogue converter (ADC) for actuator control. A typical application of a smart sensor set up is a temperature control of a furnace as illustrated below. The electronics in the smart sensor contains all the…
-
P&IDs and Loop Diagrams
Process and Instrument Diagrams (P&IDs), also called Piping and Instrumentation Diagrams and Loop diagrams are construction and documentation drawings that show the flow of the process and illustrate the instrumentation control and measurement instructions, wiring and connections to the process. The sections or subsystems of the process that are usually shown are called loops. A…
-
What is Process Control?
Process control can be defined as a control system that manages a particular industrial process so that a uniform, correct output is maintained. It does this by monitoring and adjusting the control parameters such as the flow rate or temperature to ensure the output product remains as it ought to. A typical example of process…
-
Types of Sensors used in Measurement and Process Control
A sensor is an element in a measurement system that detects the magnitude of a physical variable or parameter and changes it into a signal that can be processed by the system. The active element of a sensor is often referred to as a transducer. The monitoring and control systems require sensors to measure physical…
-
Basic Facts about Data Acquisition (DAQ) and Process Control
The goal of most electronic systems is to measure or control some physical quantity. The system will have to acquire data from the environment, process this data and record it. As a control system, it will also have to interact with the environment. The flow of information in a typical data acquisition (DAQ) can be…
-
Performance Characteristics of Digital Measurement Instruments
In this article, we discuss the performance characteristics of digital instruments i.e. Resolution Accuracy Linear errors Settling time Temperature sensitivity Monotonicity Resolution This is defined as the smallest increment in voltage that can be discerned. It is the reciprocal of the number of discrete steps in the Digital to Analog (D/A) converter input. Resolution depends…
-
Digital vs. Analog Instruments
Electronic instruments mainly voltmeters used either transistor or vacuum tubes. The later one is called The Vacuum Tube Voltmeter (VTVM) and the former one is called the Transistorized Voltmeter (TVM). In almost every field of electronics, VTVMs have been replaced by TVMs because of their numerous advantages. In TVM, due to the absence of a…
-
The Operation of a Temperature Control System for lubricating oil
Lubricating oil reduces friction between moving parts and also removes heat from the components. As a result, the oil becomes hot. This heat is removed from the lubricating oil by a cooler to prevent both the breakdown of the oil and damage to the mechanical components it serves. The lubricating oil cooler consists of a…