Functions_ advantages and disadvantages of programmable logic controllers _PLCs_

Document Sample
Functions_ advantages and disadvantages of programmable logic controllers _PLCs_ Powered By Docstoc
					?the function and usefulness of the PLC can be said is almost unlimited. But in
practice can be divided in general and specific.
In general, the function of PLC are as follows:
1. Control Sequential
PLC processing binary input signals into outputs that are used for the purposes of
processing techniques sequentially (sequential), here the PLC to maintain that all the
step / steps in a sequential process takes place in the proper sequence.
2. Plant Monitoring
PLC continuously monitors a system (e.g. temperature, pressure, level of altitude) and
take necessary action in connection with a controlled process (for example, already
exceeds the limit value) or displays a message to the operators.

Advantage of the PLC
1. Flexible
2. Having a lot of contact
3. Lower costs
4. Safe
5. It can be observed visually
6. Fast operating times
7. Relatively easy in terms of programming
8. High level of reliability and low maintenance
9. Easy to order components in terms of
10. The documentation was easy to do
11. Security in terms of programming
12. Adaptive to changes in production

Disadvantage of the PLC
1. Because it is a new technology, so that should require training.
2. Some applications that perform a single function, is not efficient in the use of PLC.
3. Limited usage environments, high temperatures and harsh vibrations can disrupt
electronic equipment on the PLC.
4. Need extra security equipment such as really.
5. PLC is not considered necessary when applied to industrial systems that do not
need to change the wiring.