Guide to Selecting an Automation Controls System

Automation Controls System PLC

Andrews Cooper helps you consider and define the right automation controls system platform for your prototyping, testing equipment, and production work cells.

The gap between industrial and non-industrial controls platforms is closing fast. Broad market demand for cost effective solutions have made it possible for controls technologies to evolve and cross over from a strictly industrial, rugged environment to light industrial, office, and even personal application.

This trend has led to the rising popularity of leveraging general-purpose controllers for use in automation and manufacturing environments.

But what are the limits? And with an increasing variety of products in the market to choose from, how do you know you are making the right choice for your specific application?

Today we’d like to share some of our insights – considerations that will impact your decision to go with either a general purpose or dedicated controller for your automation controls system. These considerations are built upon Andrews Cooper’s extensive and varied experience across industries and platforms. But don’t stop here, reach out to us today for a direct, no-cost, and personalized automation assessment based on your unique variables. We’re here to help!

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Automation Controls System PLC
Automation Controls System PLC

1) What are your Real-Time Processing requirements?

Are they rigid or flexible?

System processing delays or interferences are either manageable or completely detrimental to the system as a whole. If you select application system software that runs on top of an operating system (i.e. Windows, Linux, Android, etc.), remember to consider the inherent processing delays that often arise due to the demand of competing software applications or overhead task response times.

Example: If your OS is processing a Proportional Integral Derivative (PID) control loop to control chiller temperature, then any lag can potentially compromise the responsiveness of the PID control loop. This doesn’t mean you can’t use an application over a legacy PLC, but if your real-time processing requirement is high, consider employing a more suitable choice by selecting either an industrial controller, general purpose controller with specific firmware, or application running on top of a real-time operating system (RTOS).

2) Does the platform deliver the Reliability you need?

The reliability of your automation controls system is crucial for a production environment because every downtime incident affects the bottom line of the company. Unfortunately, during the prototyping stage, reliability often takes a back seat to flexibility.

As you consider the type of control system your process requires, think ahead to what could impact the reliability of your system? Consider when the next major change to your process might impact the requirements of the system, or how a next-generation product or prototype could deliver greater reliability which could prompt you to replace the system, or what kind of scenario would push you to upgrade from a prototyping to a production system.

Example: General-purpose PCs and controllers can typically withstand light to average use for 2–3 years before failures begin to occur. But utilizing these controllers in a 24/7 production environment that is expected to perform with high operational uptime for the next 5-10 years would not be appropriate. However, for products with a shorter expected lifecycle these types of controllers may make sense for your application.

3) What kind of Support does the platform require and/or offer?

3.1 The eventual cost of obsolete hardware/software

With PCs, obsolescence is an important consideration because the hardware and/or software platform is often the cause. Whereas most industrial controller manufacturers usually expand their support beyond the warranty period and include a migration path to the latest platform.

Example: During the recent end-of-support impact of the obsolescence of Windows 7, we witnessed customers burdened with expensive application rewrites to keep multiple control systems functional. Some preferred to actually remove their automation system from their network to avoid potential online security vulnerabilities. Others found themselves hunting through eBay and secondary market for replacement hardware – a task no production manager wants. Although a PC platform is often a less costly option, is the trade-off away from a more costly industrial platform worth it? For your situation, does the higher cost of industrial controller support (over its consumer-level sibling) make more sense because it delivers a higher level of support?

3.2 The path and cost to Rewrite, Migrate, or Upgrade

A well-supported controls platform will have a clear path to identify whether you would need to rewrite, migrate, or upgrade your controls system and keep the re-work to a minimum. This choice is usually necessary as a result of an obsolete control system or a desire to upgrade for a higher level of performance. Think about the cost and path for each platform if/when either of these decisions becomes a reality.

3.3 How Resources and platform support should factor in

The availability of internal or external resources, whether expertise is provided by subscription or at no cost, should be considered before you select a platform.

Most industrial solutions are acquired through a specialized provider with a paid subscription or one-time fee which garners ongoing support and proven application cases to leverage.

With an open source solution, there are no subscription costs, but diligence and experience are required to gather studies and application notes that help you design your solution. And when challenges arise, support is only available through the open source community and your own internal resources to tackle and solve the issue. A well-supported controls system platform has a good community of adopters using it for similar applications.

3.4 The geographical location and accessibility of support

One of the most beneficial aspects of the support for your platform is whether you can access that support locally, or at least in the same geographical region. When your internal resources are limited, the location and accessibility of the support offered with your platform becomes even more essential.

If, however, your platform can be supported through a secure gateway into your network, then local/regional support is less important. In this case, it’s more critical that you and the manufacturer/integrator can ensure adequate connectivity for any remote support you need.

4) Do you have Precedence and Internal Capabilities to factor in?

If you already have automation in house, deciding on a controls system for a new piece of equipment may be easy. Utilizing the same platform already in use on other equipment takes advantage of common spare parts and current in-house knowledge of the controls platform. These two factors greatly increase the supportability and maintainability of the system, and the real cost of ownership is known and likely to carry more weight in the decision over any initial savings when purchasing the equipment.

The exception to this consideration is when the existing platform is not scalable and/or is prone to obsolescence. Migrating to a scalable and supported industrial platform will benefit in the long term.

5) Is the platform able to meet your Scalability needs?

If you were an early adopter of automation, scalability can be your Achilles heel when selecting an automation platform. Having spares and being familiar with a system doesn’t go very far if the system is simply not capable of scaling to larger I/O counts, servo motor control, or faster scan rates for faster processes. Make sure to look down the road at where the program is headed to ensure you will not be limited by your controller choice.

Example: A robust industrial automation platform will be able to perform with less than 16 I/O counts and go up to 1000+ I/O counts and provide you with maximum controller software reuse. Imagine the lifecycle of the process and determine if the process will eventually be duplicated in a production environment. A well-developed prototype platform is scalable to a production platform while maximizing reusability and minimizing rework.

6) Edit online or offline? Does the platform help you with uptime, or contribute to downtime?

During the process of integration or optimization of an automation project, it’s typical to make changes and improvements to the software. Platforms that are only capable of offline edits will require downtime while the controls software is being upgraded. Depending on the complexity of the automation system and the need for it to be available, this downtime can be very significant.

Example: A controls platforms that can only be edited when the system is offline will have a lower cost, but usually the offline requirement creates downtime impacts to your process. With an online-capable platform, you will spend more, but it allows many kinds of modifications while it’s the system is operating. When done correctly, online edits can yield to minimal or no downtime. Most high-end industrial platforms are even capable of handling online edits by multiple engineers, which is advantageous on a complex automation project that requires a short lead time.

7) How much Integration Time is required by the platform?

The time it takes to both engineer and debug an automation process is the integration time you need to consider. On a mature controls system platform, this time can be reduced by the experience of the integrator and the knowledgebase availability. This is critical as more time can be spent in optimizing the system rather than developing a platform.

8) Are you looking holistically at the Overall Solution Cost?

The lowest cost controls platform may not always lead to the lowest cost overall solution. By looking at multiple considerations and factors, you use a holistic approach, which usually leads to making the best platform selection.

It may be helpful to know that some of the leading industrial controller manufacturers are starting to introduce low cost platforms that are scalable to their full-fledged, state-of-the-art controllers. This is good news for smaller automation projects where the cost of the industrial grade controller has been prohibitive in the past.

Automation Controls System PLC

Define Your Challenges

Creating a clean definition of these considerations before you select an automation controls platform is critical to budgeting, scheduling, and the overall success of the project.

Andrews Cooper is ready to partner with you and can help ensure your success during the project definition phase. We can help ensure a smooth path forward for your project and reduce any surprises along the way.

We have built a business focused on solving real engineering problems and helping you automate difficult processes. Our diverse experience and deep expertise allow us to serve you at the highest level. We have found that a partnership approach is the best way to ensure the job is done right. We offer these insights to stimulate conversation and help resolve ambiguity so you develop a clear and focused path forward.

Check out these Spotlights for more information:
AC Spotlight – R&D Automation
AC Spotlight – Manufacturing Automation

Contributors:

Irawan Gunadi - Controls Manager

Controls Engineering Manager

Francesca Weeks

Senior Technical Writer

Lindsay Fritz Palmer - Marketing Manager

Marketing Manager

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