PLC Important Questions


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You can find the PLC important questions with answers useful for your preparation. Also share your PLC doubts.

What are the basic functions of computer aided process control system?

Answer:

i. Measurement and data aquasition
ii. Data Conversion with scaling and Checking.
iii. Visual Display
iv. Comparing with Limits and alarm raising
v. Data Logging and computation
vi. Control action
vii. Rrecording and monitoring of events , sequence and trends

Define SCADA.

Supervisory Control and Data Acquisition (SCADA) system is computerised hardware and software based project that provides a single integrated view of all control and information resources, enable engineers, supervisors, operators to view and interact with the working of an entire operation through graphical representation of their product process.

List the functionalities of SCADA.

a. Access control
b. MMI
c. Trending
d. Alarm handling
e. Automation
f. Logging/Archiving and report generation.

Mention some of the application areas of SCADA

Industrial process: chemical plants, power generation and distribution, Metallurgy etc and nuclear process: reactors, nuclear waste etc.

List the potential benefits of SCADA.

a. Educed site visits and callouts
b. Predictive maintenance which allows proactive rather than reactive planning
c. The ability to view and adjust set points remotely
d. Reliability and robustness
e. Maximize productivity
f. Improve product quality
g. Reduce your operating and maintenance costs
h. Integrate with your business systems
i. Preserve your capital investment

What is CIMPLICITY?

CIMPLICITY is a SCADA package. It is based on a client server architecture consisting of servers and viewers. Servers are responsible for the collection and distribution of data. Viewers connect into servers and have full access to the collected data for viewing and control actions.

What is SCADA? Give any four editors available in SCADA package .

Supervisory Control and Data Acquisition (SCADA) system is computerised hardware and software based project that provides a single integrated view of all control and information resources, enable engineers, supervisors, operators to view and interact with the working of an entire operation through graphical representation of their product process.

Four editors:

a. Inkscape SAGE - SCADA Animation Graphic Editor
b. Generic Logic
c. TRACE MODE
d. UCanCode

What is the significance of DCS?

DCS is used for interfacing and computing functions and also provides the means of communication between the other devices. It consists of local control unit, low level interface, high level interface, shared communication facility Etc

Mention any four advantages of DCS

a. More reliable
b. Good scalability and expandability
c. Installation Cost is lower than centralized system which performs the same function.
d. Excellent maintainability.

What is LCU?

Answer:

Local control unit is the small collection of hard ware in the system that can do closed loop control. Local control unit interfaces directly to the process

What is the need can be satisfied in designing an industrial grade LCU?

Flexibility of changing the control configuration Ability to use the controller without being a computer expert. Ability to bypass the controller in case it fails. So that the process still can becontrolled manually. Ability of the LCU to communicate with other LCUs and other elements in system