Tag: instrumentation
-
Types of Ultrasonic Non-Destructive Testing (NDT) Techniques
The technology of ultrasonic testing has been used by production and industry since the development of the radio engineering process. The effect and device of the technology are that ultrasonic waves of acoustic type do not change the rectilinear trajectory of motion when passing through a homogeneous medium. The ultrasonic method is also used to…
-
The Principle of Operation of Optical Encoders
An encoder is a device that provides a digital output as a result of an angular or linear displacement. The position encoders can be grouped into two categories: Incremental Encoders Let’s consider the basic form of an incremental encoder for the measurement of angular displacement of shaft shown below: The incremental encoder shown above consists…
-
Features of Analog Signal Transmission
Analog voltage or current signals are hardwired between the transmitter and the receiver. These analog signals can be relatively be slow to settle compared to digital signals, due time constant of the lead capacitance, inductance and resistance. Analog signals can lose accuracy if the signal lines are long with high resistance. These signals can be…
-
The Construction & Principle of Operation of Load Cells
A load cell converts a force (usually the gravitation force from an object being weighed) to a strain which can then be converted to an electrical signal by strain gauges. A load cell will typically have a local circuit as illustrated in figure 1(a) with four gauges; two in compression and two in tension and…
-
Features & Configuration of a Smart Pressure Transmitter
Smart/Intelligent pressure transmitters are microprocessor-based, and they provide additional functional capabilities beyond their basic role of just sensing and representing a process variable; for example they provide computing, diagnostics, and networking capabilities . We shall consider a capacitive sensing pressure transmitter with a typical functional diagram illustrated below: The process pressure is transmitted through the…
-
Basic Features of Controller Area Network (CAN)
Controller Area Network (CAN) is a serial communication protocol developed primarily for applications in the automotive industry. It is also capable of offering good performance in other time-critical industrial applications. The CAN protocol is optimized for short messages and uses a carrier sense multiple access (CSMA)/Arbitration message priority (AMP) medium access control technique. Therefore CAN…
-
Technical Aspects of Foundation Fieldbus
Foundation fieldbus (FF) is an all-digital, serial, two-way communication system for industrial applications. Foundation fieldbus specifications include two different configurations: H1 and HSE. H1 Foundation Fieldbus (FF) H1 FF communication system is mainly applied to distributed continuous process control; running at 31.25 kbps. It connects digital field equipment such as sensors, actuators and inputs/outputs allowing…
-
Topological Network Structures used in Fieldbus Systems
Topology is an important property of fieldbus. It is employed in the selection and definition of the best and suitable physical layout of the fieldbus network. The physical layer of the fieldbus has to meet somewhat demanding requirements like immunity to electromagnetic disturbances, robustness, intrinsic safety for hazardous areas, etc. The most important topologies for…
-
What is Fieldbus in Industrial Communication Networks?
Fieldbus can be defined as a digital, serial, multidrop, data bus for communication with industrial control and instrumentation devices such as sensors, transducers/transmitters, actuators, local controllers, etc. Alternatively, Fieldbus can be defined as a digital, two-way, multidrop communication link among intelligent or smart measurement and control devices. It serves as a local area network (LAN)…