SAIMC Chair Ann de Beer and Yokogawa’s Anton van der Linde.
The SAIMC Johannesburg branch August technical evening was hosted by Yokogawa, and attendees learnt about the differences between a programmable logic controller (PLC) and a distributed control system (DCS). Yokogawa’s Anton van der Linde discussed where PLCs came from, some PLC theory, and why combinations of these systems might be used.
In bygone years when all manufacturing processes were manual, General Motors looked to an automated system was would be easily programmed, maintained and reused. PLCs were initially used for digital control and energy management in plants. DCSs came about as a method to bring numerous controllers and networks together and distribute the information to the necessary areas of the plant. A DCS system is generally a software platform for everything with enhanced database, PID control, graphics and tags, and works from the field devices to a controller running on one network.
Van der Linde went through the different applications of the two systems, going through the considerations plant managers should look at when deciding what is right for them.
As always, lively discussion followed the presentation, with some attendees bringing applications and alternative arguments to the fore.
Contact Laura van der Merwe, SAIMC, jhb.secretary@saimc.co.za
