Showing posts from October, 2022


Instruments Basically an instrument is a man made device which is used to measure a parameter of a physical variable. And it is variable analog as well as digital or a combination of digital and analog. Generally most industrial instrument is digital because digital instrument has more advantages compared to analog instrument . But in most cases the front end instrument is still analog and most signals from sensors or transducers are analog . Most sensors have the form of a chip and this smart sensor is directly connected or digital devices. The most basic and elementary components in all devices are sensors and transducers. Basically these outputs are current, voltage and power or amplitude, frequency or phase difference of energy. And all devices operate on signals. A signal is detected by a sensor from physical phenomena. The difference between analog and digital instruments is signal processing, and it requires different theoretical approaches and hardware. You may also like this:

Control System

Control System Control System Questions and Answers Q. What is the tuning of controllers? Tuning basically involves proportional adjustment. Integral and derivative parameters to get better control. The gain, time constant and dead times around the loop will determine the settings of various parameters of the controller. Q. What is the proportional control only? Proportional control attempts to return the measurement to the set point after the load is upset. It is however impossible for a standard controller to return measurements to a fixed point. You may also like this:   Control System Simulation Q. What is the use of proportional control only? It is commonly used for level control. It reduces the effect of load change but cannot eliminate it. Q. What is proportional plus reset control? A reset action is initiated to remove the offset. It will integrate the difference between the measurement and the set point and change the output of the controller until the difference between the m

Bipolar Junction Transistor

Bipolar Junction Transistor What is Bipolar Junction Transistor? A bipolar junction transistor is a BJT. A bipolar junction transistor is a three terminal semiconductor device that acts as a static switch or amplifier. And BJT is also called transistor. The name BJT, stands for Transistor, is derived from two words 'transfer' and 'resistor'. Because these two words can describe the operation of a BJT, which is the transfer of a signal from a low-resistance circuit to a high-resistance circuit. Basically a bipolar transistor is a 3 terminal semiconductor device. It consists of two types of semiconductor material, p-type (positive type) and n-type (negative type), and current flows through these regions. Construction of Bipolar Junction Transistor A bipolar junction transistor is formed by sandwiching a p-type or n-type semiconductor between two layers of n-type or p-type semiconductor as shown in the figure. A metal contact is connected to each of the three layers that a

What is a tapered thread pipe fitting?

Thread Pipe Fitting What is a tapered thread pipe fitting? Threaded fittings are commonly used to make connections between pipes and certain treatments. The most common design of threaded pipe fittings is the tapered pipe thread design. The purpose of the tapered thread is to allow the pipe and fitting to "wedge" together when engaged, creating a mechanically tight and leak-free joint. When male and female tapered pipe threads are first engaged, they form a loose junction. There are several different standards available for tapered-thread fittings. For each standard, the angle of the thread is determined in the same way as the angle of the taper. The number of threads per unit length of thread varies with the diameter of the pipe fitting. Some type of sealant is applied to the NPT pipe threads to ensure a pressure tight seal. Teflon tape as well as various liquid pipe dope compounds work well for these purposes. Sealants with NPT threads are needed for two reasons. Lubricate

Measurement and Instrumentation Questions and Answers

Measurement and Instrumentation Questions and Answers  1. For measurement of low resistances, Kelvin's double bridge has high accuracy because: a. It has two sets of ratio arms which eliminate the effects resistance of connecting lead b. It has a galvanometer indicating zero c. It has two null pointers d. It has four sets of ratio arms that eliminate effect of resistance of connecting lead Answer: It has two sets of ratio arms which eliminate the effects resistance of connecting lead 2. Swamp resistance is a built-up resistance_____________ a. An alloy of Manganese and Copper b. An alloy of aluminum and copper c. Alloys of nickel and cobalt d. Alloys of Manganese and Aluminum Answer: An alloy of Manganese and Copper 3. A meter of swamping resistance in a moving coil added in ______ a. Minimize frequency error b. Reduce temperature error c. Reduce electricity consumption d. All of these Answer: Reduce temperature error 4. Frequency error in induction devices can be compensated by us

What are flange pipe fittings?

What are flange pipe fittings? A flange pipe fitting is a fitting used to connect valves, pumps and other piping system equipment, basically these fittings are connected with the help of nuts and bolts. And flange joints are compressed by inserting donut-shaped gaskets before the bolts are tightened. A flange is an external or internal part used to connect pipes, valves and other equipment or to connect a piping system. Flange joints are mainly used on equipment joints like pipes, valves where frequent maintenance is required. A flange is a reinforcement or connection to another object, such as a flange at the end of a pipe, and flanges are used when joints need to be separated. Flange A flange is basically a metal ring that connects to a pipe or valve and other system. And usually this flange is attached to the end of the pipe and this flange has some holes to connect another flange using nut and bolt. The flange joints are pressure tightened by inserting donut-shaped gaskets before t

Instrument identification tag

Instrument identification tag AIT:  Analytical Indicator Transmitter (eg oxygen concentration analyzer with built-in display of oxygen percentage) ESL : Voltage switch, low (a switch used to detect under-voltage conditions in an electrical power system) FFI : Flow Ratio Indicator (a device that indicates the ratio between air and fuel for large industrial engines) FIC:  Flow Indicating Controller (and is a controller designed to indicate flow to a human operator) HC:  Hand controller (and is a device that allows a human operator to set a control signal to some desired level, usually to operate a valve or other final control element) JQR: Power totalizing recorder (eg watt-hour recorder, tracking total energy used) LSHH: level switch, high-high (for example, a level-sensing switch designed to detect dangerously high liquid levels and initiate an automatic shutdown in that event) LT: Level Transmitter (and is a device that detects liquid level and reports that level in some analog or dig

What is a recorder?

What is a recorder? Recorder Basically the recorder is a common auxiliary device and is used to graph the process variable. Recorders usually have indicators built into them to show the instantaneous value of the instrument signal along with historical values, and for this reason are commonly designated recorder indicators. Circular chart recorder A circular chart recorder uses a round sheet of paper, moving slowly under the pen and moving sideways by a servomechanism driven by an instrument signal. Bar chart recorder A strip chart recorder uses a scroll of paper drawn gently behind one or more side-moving pens, while a paperless recorder eliminates paper entirely by plotting graphic trend lines on a computer screen. Recorders are extremely useful for troubleshooting process control problems. This is especially true when the recorder is configured to record not only the process variable but also the setpoint and output variables of the controller.

What is Indicator and its Example

What is Indicator and its Example Indicator Essentially an indicator is a common auxiliary device and is used to provide a human readable indication of an instrument signal. And an inductor is basically a distance amplifier. Inductors are used to accurately measure small distances or angles. The indicator gives the human operator a convenient way to see what the output of the transmitter is without connecting test equipment. Furthermore, the indicators can be located away from their respective transmitters, providing a readout at a location more convenient than the location of the transmitter. Indicators are a measuring tool so they are used to indicate. And to understand what the data on the indicators actually shows, some basic understanding of elementary statistics is required. Also the ability to understand the data will help you adjust, challenge or change the indicators being used. A good indicator is a measure of an excellent system. Indicative Example Temperature Indicator The

Introduction to Industrial Measurement

Introduction to Industrial Measurement Various types of control systems and instruments are used in industry to complete the process and basically to measure and calibrate the process. Simple industrial measurements are fluid pressure, fluid flow, system or object temperature, environmental temperature, fluid volume, chemical concentration, system acceleration, device speed or position, object physical diameter and device voltage, current, resistance, etc. Fluid Pressure Measurement: This parameter measures the pressure of a fluid or object using various types of devices or sensors. And there are two types of this measurement manual measurement and automatic measurement. A common automatic gauge is used to measure fluid pressure and a differential pressure sensor is used in this measurement. Fluid Flow Rate: The this parameter measures the fluid flow throughout a pipe or object, and the this measurement uses a variety of sensors to measure fluid flow. And generally measure this parame