What are Manufacturing Execution Systems (MES)?

These diverse systems function in real-time to control and monitor the various elements of a production process. These elements can include the actual raw materials (input), people, the machines that make up the line, and any supporting services such as maintenance and configuration.

MES are used to define the equipment needed to produce the product (the recipe), then capture the data and outcomes of the processes being exercised. A MES is quite often integrated to resource planning and production analysis tools to evaluate production needs and to manage equipment reliability, availability, and effectiveness. The data coming out of these systems can be used for decision making and predictive analyses to foster improvements in process and procedure.


How do they relate to other familiar systems?

The boundaries of functionality and responsibility between a MES, ERP, EAM, and SCADA systems can be blurred. Enterprise Resource Planning, Enterprise Asset Management, and Supervisory Control / Data Acquisition solutions all have substantive and wide-ranging functions available to us. Industry groups such as MESA International assist in the implementation of and definitions around MES. Another excellent source of industry information is the MES Center Association.


Where do they play a role in operations?

The architecture of a MES system is described in the ANSI/ISA-95 industry standard. For perspective, in this standard an ERP is considered at Level 4 (the top level), while a MES is at Level 3. Levels 0, 1, and 2 are at the process control level of functionality.

Other familiar systems operating at Level 3 are:

  • LIMS – Laboratory Information Management Systems
  • WMS – Warehouse Management Systems
  • CMMS – Computerized Maintenance Management Systems

Typical data flowing to/from the MES and the other levels include results, requests, definitions, events, and process or equipment status/condition data. These streams of data come up from the lower levels of the architecture. Level 2 and below is where the SCADA systems and the PLCs (programable logic controllers) reside. The actual real-time data values, alarms, and production results are coming from these levels.


Where is the technology headed?

There is a published standard for “plant floor connectivity.” It began as OLE for Process Control (OPC) but has moved to OPC Unified Architecture (OPC-UA) to expand its capability across modern software platforms. The IEC 62541 standard is also related to OPC. It is also worth mentioning that OPC-UA has APIs written in the most common programming languages, enabling interfacing across systems. The OPC-UA specification addresses the elements of the potential data interactions. Formats for alerts, conditions, services, and aggregates are a few.

A trend in the MES world is for greater system collaboration capabilities to foster flexibility yet maintain the rules necessary to produce quality products. Historically, a MES has been a collection of database interconnections and purpose-built applications, making for less than reliable results and difficulty in system maintenance and further development. Modern systems are bringing the disparate sources of data into a federated point for visualization, analysis, and decision-making.


MES – a good source of equipment data

As we move towards empowering maintenance with AI and other learning tools, connecting to the growing sources of data is an important consideration. Add this to the plethora of MES systems that are available to us, there is much to explore.

TRM has the experience working with clients who wish to take advantage of the data coming from their equipment whether from an MES or other system. Whether it be to support a condition-based maintenance program or to explore the use of AI tools and models to actively reduce failures and costs, TRM has the solutions and the knowledge needed for you to be successful.


Article by John Q. Todd, Sr. Business Consultant at TRM. Reach out to us at AskTRM@trmnet.com if you have any questions or would like to discuss deploying MAS 8 or Maximo AAM for condition based maintenance / monitoring.