Abstract
Most automated industrial processes use Distributed Control Systems (DCSs) or Programmable Logic Controllers
(PLCs) for automated control. PLCs tend to be more common as they have much of the functionality of DCSs, although
they are generally cheaper to install and maintain. PLCs in conjunction with a human machine interface form the basis of
Supervisory Control And Data Acquisition (SCADA) systems, combined with communication infrastructure and Remote
Terminal Units (RTUs). RTU's basically convert different sensor measurands in to digital data that is sent back to the
PLC or supervisory system. Optical fibre sensors are becoming more common in industrial processes because of their
many advantageous properties. Being small, lightweight, highly sensitive, and immune to electromagnetic interference,
means they are an ideal solution for a variety of diverse sensing applications. Here, we have developed a PLC Optical
Fibre Sensor Interface Module (OFSIM), in which an optical fibre is connected directly to the OFSIM located next to the
PLC. The embedded fibre Bragg grating sensors, are highly sensitive and can detect a number of different measurands
such as temperature, pressure and strain without the need for a power supply.
