“…. applications areas that were impossible to address with PLCs are now addressable”

Chandran Nair is the Managing Director of National Instruments Singapore, which is the company’s hea

CE Asia: How are technologies evolving in industrial measurement and control?

Chandran: For the last decade a passionate debate has raged about the advantages and disadvantages of PLCs (programmable logic controllers) compared to PC-based control.

As the technological differences between PC and PLC wane, with PLCs using commercial off the shelf (COTS) hardware and PC systems incorporating real-time operating systems, a new class of controllers, the PAC is emerging. PAC, a new acronym created by Automation Research Corporation (ARC), stands for Programmable Automation Controller and is used to describe a new generation of industrial controllers that combine the functionality of a PLC and a PC. The PAC acronym is being used both by traditional PLC vendors to describe their high end systems and by PC control companies to describe their industrial control platforms.

Many industrial applications collect high speed measurements for vibration or power quality applications. The collected data is used to monitor the condition of rotating machinery, determine maintenance schedules, identify motor wear, and adjust control algorithms. The data is normally collected using specialized data acquisition systems or stand alone instrumentation and is incorporated into a control system using a communication bus. PACs can directly take high accuracy measurements at millions of samples per second, which are then passed directly into their control systems for immediate processing.

Engineers also can incorporate machine vision into their control systems. Vision is an area of automation that has gained a lot of momentum in the last decade. In a manufacturing environment, there are many flaws or mistakes that can be identified through visual inspection that are difficult to detect using traditional measurement techniques. Common applications include part inspection for manufacturing or assembly verification, such as checking for correct component placement on a circuit board, optical character recognition (OCR) to examine date codes or to sort products, and optical measurements to find flaws in products or for sorting based on quality criteria. Many plants currently use stand-alone smart cameras that need to communicate to the manufacturing process controller.

CE Asia: Can PC-based control replace PLCs altogether?

Chandran: As I explained earlier the line now is very fuzzy. All the high-end PLCs are often marketed as programmable automation controllers. Traditional PLCs still play a role in the simple low-end applications that are primarily controlling digital states and those that require limited intelligence at each node. Essentially because of the reduced cost and tremendous performance improvements in semiconductor technology, engineers are finding effective ways to meet application challenges by adding more processors and more intelligence to their systems. As a result, the products that are designed, as well as the systems developed for testing and controlling these products, are becoming more distributed. The introduction of single platform software tools like National Instruments LabVIEW that help engineers program on PCs, PACs, FPGAs, DSPs, and microprocessors has enhanced the use of PACs in multiple application areas that PLCs could not address. So really the comparison of PLC and PAC is an out dated idea. The real question is what new applications areas that were impossible to address with PLCs are now addressable.

CE Asia: How do you see the uptake of NI technology in the Asian market?

Chandran: NI technology is being widely adopted in Asia. China, India, Korea, Singapore, Malaysia, Thailand, and more recently Philippines, Indonesia and Vietnam have seen significant growth in the adoption of this technology. The paradigm of Virtual Instrumentation and Control really focuses on the engineer and scientists, enabling them to make “user-defined” solutions as opposed to the traditional approach of “vendor-defined” solutions. As the economies in this region have picked up and the desire of the local engineers to add value has increased, so has the adoption rate of our technology.