PLC and DCS?
A Programmable Logic Controller (PLC) is a miniature industrial computer (CPU) that contains the hardware and software for the automation of industrial electromechanical processes of machinery. Distributed Control System (DCS) is a computerised control system for a process or plant usually with a large number of control loops, in which autonomous controllers are distributed throughout the system, but there is central operator supervisory control.
PLC is usually used for controlling medium or large-scale applications, whereas DCS is used for controlling an entire plant.
Since their inception in 1968, Programmable Logic Controllers are now utilised in every facet of life; from controlling air conditioning systems in shopping malls to complex production lines at major car manufacturing facilities.At Axxa, we offer the most comprehensive, economical and reliable repair service for programmable logic Computer Numerical Controls (CNC), Programmable Logic Controls (PLCs), Distributed Control Systems (DCS) and programmable automation controllers (PACs) for a vast range of brands.
PLCs come with an array of benefits and advantages over non-programmable controllers:
- Increased reliability
- Decreased energy use
- Reduced space requirement
- Increased flexibility of use
- You can manage multiple machines simultaneously
- Higher levels of machine integration and process automation
- Increased production
- Lower operational costs
Multiple digital and analog inputs and outputs (I/O interface systems) can be programmedwith…
- Extended temperature ranges
- Immunity to electrical noise and
- Resistance to vibration and impact
PLCs Run a Four-Step Operational Process in a Recurring Loop
- Input Scan:Scans for all connected input devices
- Program Scan: Execution of user-created program logic
- Output Scan: Runs or shuts off all connected output devices
- Housekeeping: communicates with programming devices and performs internal diagnostics
And you can connect a lot of things to a PLC:
- All types of drives, sensors and output devices namely:
- Drives
- Remote I/O
- Limit Switches
- Sensors
- Other control devices
- Operator interfaces
- Other PLCs
Choosing a Controller
Select the right controller for the job by determining ahead of time what you need your system to do and the specifics about the system itself.
Here is a sample of few of the questions to ask when you are deciding on a controller for your next system.
Looking for a new or an existing system? If it’s an existing one; How old is it?
What environmental conditions the system will be installed? Hot!Dusty!Noisy and full ofVibrations!
Discrete components of the system? Are they AC Devices or DC Devices?
Number of analog devices?
Any special features in the system needed? A real-time clock or high-end positioning?
Amount of memory the CPU needs to run the system efficiently?
Location of I/O devices? Local only or local and remote?
Will the Controller be communicating with other systems or networks or field devices?
Require traditional programming instructions or special instructions needed?
Each of these questions explores a distinct set of requirements to help you to the selection of right controller.
