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What is the difference between SCADA and DCS?
Supervisory Control And Data Acquisition (SCADA) generally refers to an industrial control system — a computer system monitoring and controlling a process. Normally, a SCADA system will get data from a RTU (remote terminal unit). A RTU runs independently, except for some control from the central supervisory system such as fire fighting or emergency shut-down (i.e. water & oil pipelines).
A distributed control system (DCS) refers to a control system usually of a manufacturing system or process or any kind of dynamic system in which the controller elements are not centrally located but are distributed throughout the system with each component sub-system controlled by one or more controllers. The entire system of controllers is connected by networks for communication and monitoring. SCADA systems are used to gather and store data and DCS systems are used to control processes. |
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What is the difference between licensed and unlicensed radios?
Licensed radio are broadcast at high power (1 Watt or greater) and the bandwidth are owned by public or private entities. Unlicensed radio broadcasts at low power (1 Watt or less) and are open to all users. Radio users lease licensed radio bandwidth from private companies for a fee but the signal strength is usually high. Unlicensed radios bandwidth is free but the signal is weaker. Furthermore, overuse of unlicensed radios in an area can diminish the effectiveness of those radios. |
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What is web hosting?
Web hosting is when a second party runs an operation (such as a SCADA system) on its server for the first party. |
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What is the difference between an Electronic Flow Meter and Ultrasonic Electronic Flow Meter?
Electric Flow Meter (EFM) measures the fluid flow (liquid or gas). Usually, pressure and temperature transmitters measure the static pressure, temperature and differential pressure across an orifice. The EFM calculates the fluid flows from temperature, static pressure and differential pressure.
Ultrasonic Electronic Flow Meter also measures fluid flow (liquid or gas). An ultrasonic EFM consists of an ultrasonic meter, pressure transmitter and temperature transmitter. The ultrasonic meter measures the speed of gas by measuring the speed of ultrasound travels through the gaseous medium. Ultrasonic EFMs are more precise and more expensive than normal EFMs. |
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What is the difference between a serial network and a parallel network?
Serial communication is the process of sending data one bit at one time, sequentially, over a communication channel or computer bus. In parallel communication, several bits are sent together on a link with several parallel channels. Serial communication is used for all long-haul communication and most computer networks, where the cost of cable and synchronization difficulties makes parallel communication impractical. Parallel networks are used for short distance communication to transfer and manipulate data faster. |
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What is an RTU and PLC and what are the differences?
An RTU, or Remote Terminal Unit, is a microprocessor controlled electronic device that interfaces objects in the physical world to a distributed control system or SCADA system by transmitting telemetry data to the system and/or altering the state of connected objects based on control messages received from the system.
A programmable logic controller (PLC) or programmable controller is a digital computer used for automation of electromechanical processes.
Currently, RTU and PLC functions overlap, but traditional RTUs are used for wide geographic telemetry and PLCs are best suited for local area control. |
