What is a URS for industrial process automation? 
In simplest terms, a process automation User Requirement Specification (URS) document defines what the automation system needs to do to satisfy the needs of the business. 
The URS document is a critical, yet often overlooked, initial step in building and implementing a new or updated process automation system. Many times, this step is simply skipped, or left to the final system integrator. However, system integrators tend to provide solutions that are expedient from an installation point of view, and may not consider new solutions that would better support the business. These new solutions may require new additional partners coming from disciplines such as Information Technology, data science, or manufacturing and maintenance management systems. 
The URS document must be first and foremost driven by business priorities which the customer understands best. 
The URS document is a key part of the ISPE Good Automated Manufacturing Practice (GAMP) Guide for Validation of Automated Systems in Pharmaceutical Manufacture which covers the creation of automation systems for the production of pharmaceuticals. While not every process industry needs the level of rigor prescribed by this guideline, all process industries can benefit by following its philosophy and approach. 
Why create a URS for process automation? 
The automation URS document provides a means to capture stakeholders' needs and help ensure that all parties know and agree on what must be accomplished. The URS strives to avoid that anyone is surprised by what the automation system does or does not do once it is commissioned and up and running. 
It is interesting to note that a well written URS helps to protect automation suppliers as well as customers from unpleasant surprises. 
Writing a good process automation URS document takes time and a bit of effort. However, this effort and time is paid back several times over with the resulting automation system being appropriate, cost effective, and truly in alignment with the needs of the business. 
It should be noted that the Industrial Internet of Things (IIOT), or Industry 4.0, is dramatically increasing the capabilities of industrial control systems. A good URS helps to create a clear vision of the way forward in harnessing these capabilities. 

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