Exceeding expectations And/Or destined for failure

You may not realize that your control system is running beyond red line in some area, and could fail at any time.

06/10/2013


Is your control system exceeding expectations by performing in an environment for which it is not rated, operating beyond its rated temperature, powering loads beyond the documented capacity, or is it destined for failure? So which is it, or is it more than one? In most cases where an issue is present, the answer is yes to more than one, including the last one: the equipment is functioning beyond rated capacity and destined for failure, yet the owner is unaware.

Over the years I have seen too many instances of control equipment being used beyond its documented limitations and expiring prematurely. Of course, when the equipment does fail it will likely be at the most inconvenient and costly time possible. Using equipment beyond its documented limitations either knowingly or in most cases out of ignorance, will result in premature equipment failure which translates into downtime and ultimately increased cost of ownership. Most all equipment and certainly all UL certified equipment has published temperature, temperature derating, voltage, current, and environment (NEMA) ratings applicable to the equipment. A UL certified control panel is a good start, but it’s not a guarantee and it’s not enough. Adhering to good design standards and practices which ensures the limitations of the equipment are not exceeded, followed up with a good internal quality control system is the recipe for developing a control system with a lower cost of ownership which can live up to the runtime hours and/or cycles published by the manufacturer.

Do you have a new project on the board, or a control system which tends to be a trouble maker and requires constant maintenance? If you plan to seek outside help, make sure you start down the right path and inquire about the company’s engineering standards and practices. Here are my top five suggestions to make sure your next control system design is going to meet your needs for years to come:

1. Ensure your supplier has good processes and standards around component selection taking into account electrical and environmental requirements.

2. Ensure your supplier has standardized procedures for preparing design deliverables such as control system cabinetry, instrumentation, etc. This might include instrument data sheets, heat calculations, power (load) calculations, and standardized drawing packages that are easy to read and facilitate future troubleshooting by operations.

3. If your company has standards, be sure your supplier is flexible enough to adopt them.

4. Ensure your supplier has robust quality control procedures to catch design errors before equipment is purchased and assembled, or worse yet, delivered to your facility.

5. Ensure your supplier is capable of meeting your facility’s area classification requirements. Look for suppliers who can supply UL 508A listed panels for normal situations or UL 698A listed panels for classified areas.

This post was written by Andy Crossman. Andy is a control system specialist at MAVERICK Technologies, a leading system integrator providing industrial automation, operational support, and control systems engineering services in the manufacturing and process industries. MAVERICK delivers expertise and consulting in a wide variety of areas including industrial automation controls, distributed control systems, manufacturing execution systems, operational strategy, and business process optimization. The company provides a full range of automation and controls services – ranging from PID controller tuning and HMI programming to serving as a main automation contractor. Additionally MAVERICK offers industrial and technical staffing services, placing on-site automation, instrumentation and controls engineers.



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