One application of simulation that does not get a lot of attention is PLC emulation.  Using a simulation engine and various communication methods, several simulation packages can provide a way to talk directly with a PLC running ladder logic.  This is advantageous because you can prove out (validate) the ladder logic before the real system exists.  This cuts down on costs and enables project managers to sleep better at night.

Seriously, validating ladder logic virtually can be done quicker and more effectively in a virtual world than it can in the real world.  An engineer at a computer can force IO to a specific state, watch the ladder logic execute and see the reaction of the entire real system without leaving the office.  On the floor, multiple people are required to force the IO and see the reaction.  

The other cost that is avoided is support personnel.  Often union labor needs to be called in to support the commissioning process on site.  Millwrights, electricians, and other labor are required to be paid just in case they are needed.  By testing ahead of time, these resources can be reduced by up to 70%.

Other cases have seen manufacturers avoiding an entire step in their process.  traditionally automated systems are partially, if not completely, set up and run off prior to final installation.  This is primarily done to ensure the operation of the controls.  Now that this can be done virtually, the projects are shorter and cheaper than they were in the past.

One last benefit, controls engineers now have remote access to automated systems around the world.  If the PLC code is changed and stops operating correctly, the logic can be emailed to the support engineer and debugged remotely on the virtual model of the plant.  This saves on travel and leads to better response times. 

For those of you who don’t know, this is a bit of a shameless plug.  Currently I work with V-Sim on a software product that does PLC emulation and I am organizing sessions for the this year’s Winter Simulation Conference in Miami.  If you have an interest in PLC emulation, visit our website, www.v-sim.com.  If you want to be involved in an emulation session at Winter Sim this year, email me at jhugan@gmail.com

Happy Modeling…..