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Posted by John Nelson

How to Choose the Right PLC for Your Application

June 9, 2020

Rockwell Automation, Siemens, GE, Modicon, Telemecanique, Automation Direct, and on and on it goes. How do you decide which manufacturer to choose for a new control system project or an in place upgrade?There are some simple questions you can answer that quickly narrow the field.

What is your situation?

Let's set the stage. Are you a start-up with little to no standards in place or are you an entrenched business with rigorous SOP's and purchasing limitations? Believe it or not, both of these scenarios present their own set of difficulties. Start-ups offer the freedom of a clean slate to craft a control system that can be as revered as fine art. Unfortunately, for many start-ups, these first critical decisions are often left up to entities that will not be responsible for the long term support of the control system. Often, parts of the control system are value engineered only to cause difficult/disastrous consequences later on. The flip side to this (with an established business) is that you may be forced to implement a less than ideal solution because standards have been established and "you shall not deviate". This is the square peg, round hole analogy where you are trying to force a product to do something that might be just outside of its capabilities. Although each manufacturer will say they do everything better than their competitors, the reality is that some do things better than others. Many controls engineers find themselves in this exact situation each day but we can help them to help themselves by answering a few questions before that next big project.8 steps for plc5 to controllogix conversion

Question 1 – Local Distribution and Support?

The first question to answer is; which manufacturers have local distribution and how good is their support? Distributor support is huge when you have a piece of equipment down and need to get it running with materials and/or expertise that you don't have on staff. Some distributors even offer 24 hour support! Distributors are invaluable for training, product updates, technical support, and assistance with costing projects just to name a few. Talk to other businesses in the region and find out who they use. Ask questions about the quality and responsiveness of the support provided. The important point to take away from this is that whatever path you choose, you are going to be on it for a long time. We routinely run across PLC’s that are 20 years old and operate as good as the day they were installed. This obviously means that long term support will be required; therefore, you need to take the time to ensure you build an exceptional relationship with your distributor of choice.

Question 2 – Who are the local integrators?

This is an honest fact about integration companies, most are affiliated with or have some preference towards a certain manufacturer. There are some manufacturer agnostic integrators out there but they are rarer than one would think. The important thing here is to speak with a lot of integrators and determine their preferences. The more data points you have, the better you can smooth the preferential spikes. Some additional questions to answer may be: How many integrators are in the area? Which manufacturer's do they support and why? How is their relationship with their local distributor? How many projects and at what scale have they successfully performed with each manufacturer in the last year? These are important questions to have answered when you start reaching outside for help on projects. As valuable as distributors are at getting materials to you, integrators are just as valuable at getting services to you.

Question 3 – What are your employees familiar with?

If you currently have employees, what is their proficiency with each manufacturer? It is easier and more cost effective to train a group of employees than it is to replace an entire control system because your engineers don’t understand a specific brand. This happens pretty frequently when controls engineers change jobs. They take their preferences and training for a certain manufacturer with them, and if they are put in a position to make purchasing decisions, they often go with what is familiar. The result, you end up stocking parts and training employees in multiple manufacturer’s equipment and software. If you are the person responsible for the hardware and software choices at your particular facility, ask yourself this question:  Does it make sense to introduce another manufacturer or should we (re)train our employees?

There is no substitute for great local support. If you can find a local distributor that you can build a relationship with, an integrator that is reputable and responsive to your needs, and a local workforce that is familiar with the manufacturer hardware/software (or willing to train), then the choice becomes much clearer.

 About the author

John is the New York Regional Manager for Hallam-ICS and also a seasoned professional in control system engineering for the past 24 years. John manages the New York team in addition to providing technical guidance and oversight of all automation projects in the region. Extensive knowledge and expertise in automation has allowed John to successfully transition from a technical to managerial role in 2012.

Read   My Hallam Story  

About Hallam-ICS

Hallam-ICS is an engineering and automation company that designs MEP systems for facilities and plants, engineers control and automation solutions, and ensures safety and regulatory compliance through arc flash studies, commissioning, and validation. Our offices are located in Massachusetts, Connecticut, New York, Vermont and North Carolina and our projects take us world-wide. 

Topics: Process Control and Plant Automation

John Nelson

By John Nelson

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June 9, 2020

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