Manufacturing Execution Systems reside in the informational space between Control Systems and Business Systems. As Control Systems operate in a Real Time fashion and Business Systems are Transactional, this raises a real quandary. MES systems must be proficient in both modes of operation.

Over the years, some MES systems have evolved from Control Systems by adding relational databases and historical archives. These have been moderately successful, however the transactional challenges of:

• Locking Data for Closed Accounting Periods,
• Rolling Back Transactions,
• Editing Historical Data, and
• Structuring the Data for Easy Ad-hoc Analysis

have usually been poorly supported. If the information cannot be easily analyzed, corrected and manipulated, it is not very useful.

Similarly, there have been MES systems that evolved from Business Systems by adding OPC drivers and PLC connectors. These have also been moderately successful, however the real time challenges of:

• Reacting Immediately to Events,
• Easy-to-Use Shop Floor Displays, and
• The Ability to Alert and Continue Operating

have usually been poorly supported. Losing a few seconds on every batch can mean the difference between a plant continuing to operate or shutting its doors.

I can remember many conversations with a plant's new accountant, who couldn't understand why we consistently had 3-5% yield losses that were not accounted for. In his mind, there should be metering and equations that explain the process accurately every time. In the real world, there are numerous variations in raw ingredients, metering errors and other disturbances that make it impossible to be accurate all the time (if ever).

The key point of this anecdote is that an MES system must deal with the realities of complex manufacturing processes, as well as communicating to the new accountant in a way that satisfies his needs. This isn't easy and is the key strength of successful MES systems (and MES Engineers).

How well does your MES system communicate with your Business System and Control System? Does it do both well? If you are transitioning from a Manufacturing Information System to a Manufacturing Execution System, these communication channels will give you the most grief.

In today's global economy, it is common to travel outside your own country to support projects for your customers. We, at SlimSoft, routinely travel to the United States and as such, we require a work visa to pass through US Customs. The NAFTA agreement simplified the procedure for Canadians obtaining visas to work in the States, and for Americans wishing to work in Canada. The most common visa is called a TN Visa and you can get one if your expertise and work falls within one of a few very specific categories. Fortunately for us, we meet the requirements and have been granted many visas over the years.

Even though it has been simplified, it can still be a very stressful experience to go through the application process. It involves quite a bit of paperwork and an interview by a Customs Officer. One wrong answer or one missing document, and you need to restart the process. Beyond wasting time, you also miss your flights and appointments. As part of our philosophy of leveraging expertise and maximizing efficiency, SlimSoft decided to hire Paul, Frank & Collins (www.pfclaw.com), a Vermont based law office, to prepare our documents whenever we need to go through the TN Visa application process. Three very successful applicatons later, we are very glad we made this choice and will continue to use this firm.

For any of you that travel between the States and Canada regularly through Vancouver, I strongly suggest you acquire a NEXUS card (www.nexus.gc.ca). It shortcuts Canada and US Customs, as well as Security lines in Canada. It will save you a lot of time. Although the NEXUS card is still in a pilot program, it is expected to become available at all border crossings, next year. It is available to both Canadian and American residents.