Introduction to MES

What is MES?

My past experience indicates that the concept of “MES” is not clear to some of the manufacturers and there is less clarity on where MES exactly fits in, in the galaxy of manufacturing systems. This article is my attempt to give clarity about MES, its components and its relationships with other key systems. I believe that pictures convey the information effectively as compared to sentences, hence I tried to put in more pictures. “ERP” is a well-known (or well understood?) terminology and concept as compared to MES. Though ERP gives quite a few critical and decision making information, the “drill-down” information or the specific details are usually not with the ERP.”MES: Manufacturing Execution System” provides such details specific to production. In short, Manufacturing Execution Systems (MES) are software solutions that ensure that quality and efficiency are built into the manufacturing process and are systematically enforced. It can also be referred as shop floor system, WIP tracking system or a traceability solution.

Why MES is needed?

MES basically helps in controlling the manufacturing process and gives detailed traceability of what you are manufacturing. It captures and gives information such as genealogy, cycle time, yield details, loss details, root cause information, quality related information, resource tracking details, employee performance etc.

With the above information MES users were able to apply the relevant changes to their process and generally seen the below benefits.

  • Improved Yields
  • Shorter NPI Time to Volume
  • Variability Reduction
  • Enforcement of Best Practices
  • Lower Operating Costs
  • Operational Efficiency gains
  • Shorter Cycle Times
  • Increased Compliance

History of MES

If we look at the history of MES, the early 1980s MES concepts originated from data collection systems. A wide variety of systems arose using collected data for a dedicated purpose. Further development of these systems during the 1990s introduced overlap in functionality. Then the Manufacturing Enterprise Solutions Association (MESA) introduced some structure by defining 11 functions that set the scope of MES. Early 2000 the ANSI/ISA-95 standard merged this model with the Purdue Reference Model (PRM). A functional hierarchy was defined in which MES was situated at level 3, between ERP at level 4 and process control at levels 0,1,2.

Figure 1. Purdue Reference Model


MES Components

Activities in level 3 were divided over four main operations: Production, Quality, Logistics and Maintenance. ANSI/ISA-95 standard defined the architecture of MES in more detail. MES in general constitutes the following eleven components as shown in the diagram below.

Figure 2. MES Components


Relationship with the Level 4 Systems

To understand MES better I have put down a diagram below which shows the relationship of MES with some of the key level 4 applications like ERP (Enterprise Resource Planning), PLM (Product Lifecycle Management), CRM (Customer Relationship Management), HRM (Human Resources Management) and key information these systems exchange with MES.

Figure 3. Relationship of MES with Level 4 Applications


Relationship with the Level 0,1,2 Systems

Level 0,1,2 applications which are mostly control systems interact with MES key decision making information like test results, control limits, out of control action plans (OCAP), recipes etc. Mostly similar information gets exchanged between MES and control systems.

Figure 4. Relationship of MES with Level 0,1,2 Applications



  • Manufacturing Enterprise Solutions Association
  • Wikipedia
  • Camstar Systems