Flashcards
PLC System ( topic 4 )
Cards in this deck (8)
- 1PLC Architecturedivided into four parts:
Input/output modules
Central processing unit (CPU)
Memory
Programming terminal - 2PLC OperationPLC works by continually scanning a program
3 Important steps :
1. CHECK INPUT STATUS (ON/OFF)
2. EXECUTE PROGRAM
3.- UPDATE OUTPUT STATUS - 3figure 2 Block Diagram Of PLCProgramming terminal
'
Power Supply -------- CPU -------- Memory
' '
input module ------ Output module
' '
input devices output devices
( process ) - 4Parts of PLC System- Central Processing Unit (CPU)
- Memory ( ROM , RAM , EPROM , EEPROM )
- Power Supply ( 24VDC )
- I/O Module - 5SwitchesNormally opened
- The switch lever will be on top of the wires and will never touch
Normally closed
- Switch lever will be at the bottom and will touch - 6Advantages Of PLCover the relay controlled system
Are more robust and reliable
Are more compact
Require less maintenance
Can operate faster
over computer
Can have inputs and outputs in the controller.
Are easily programmed and more user friendly
Have great reliability - 7Disadvantages of PLCover computer
PLC devices are proprietary, which means that the parts and software from one manufacturer cannot be used in combination with parts of another manufacturer, which limits the design and cost.
They are no good at long term data storage and analysis.
PLCs were designed for Relay Logic Ladder and have difficulty with some smart devices.
To maximize PLC performance and flexibility, a number of optional modules must be added - 8PLC Applicationsused to substitute the switching relay network used in industrial applications
used to implement timing, delaying counting, calculating, comparing & processing of analog signals
Information
- Description
- marine electronics Flashcards on PLC System ( topic 4 ) , created by izz azman on 24/08/2020.
- Created by
- izz azman
- Views
- 0
- Rating