a The following is a list of terms to do with how digital in

a) The following is a list of terms to do with how digital information is communicated between parts of a PLC and with external items such as programming panels and computers. Write a brief description of each and outline the advantages and disadvantages of each.

i. Twisted pair.

ii. Coaxial cable.

iii. Fibre optics

Solution

Solution :

Twisted pairs: Twisted pairs are nothing but two wires of a single circuit are twisted just to cancel out the electromagnetic interference from external sources.

Advantages:

1. It is easy to install and use.

2. Interference and cross talk is cacnelled out.

Disadvantages:

1. If the twisting is not made proper then there is a huge chance of interference.

2. Expensive

Coaxial cable:

In this type of cable the inner cable is covered by insuating material and around that again the second conducting layer is put up and they all share the same geometrical axis.

Advantages:

1. There is very minimal loss in the signals.

2. We can have long cable lengths here.

Diadvantages:

1. The cable wont be that much flexible.

2. Difficult to install.

Fibre optics:

This technology is nothing but use of light using drawing glass material as the mode and these are the fastest modes of transferring signals with very minimal loss and effectiveness even over 1000s of kms.

Advantages:

1. Lighter and higher capacity

2. No loss at all

Diadvantages:

1. Costly

2. Connecting two or more fibres is difficult.