Understanding the Operation and Usage of Manufacturing Execution Systems

Keysight Technologies

Understanding the Operation and Usage of Manufacturing Execution Systems

Technical Overview

Introduction

The need to integrate an ICT Test system with the Manufacturing Execution System has become increasingly common as more businesses attempt to improve production management to achieve better operational efficiency and accuracy.

Manufacturing execution system (MES) is a software package that is usually server based and requires each element on the production line to upload or download information from its database. In doing so, the MES software gains knowledge of every single piece of product on the line and can assert restrictions so as to ensure that the product follows a particular production sequence. The most common restriction is to prevent a product from being processed at a particular station on the line if it has not completed the operation prior to this.

In order to achieve proper tracking and control, every piece of product on the line must be serialized. A common method will be to use barcode labels and have each station scan the labels and upload the information to the MES server for processing. Other method may include usage of RFID instead of barcode labels.

With the product serialized, each station on the line can now scan the ID of the product and check it against the MES server to determine if that product is legible for that station to process it. In other operations, the ID of the product may also be used to determine specific information to be downloaded from the server, which will be later programmed into the product itself. One example will be the MAC Address of a network board. MAC addresses are usually strictly controlled by the server to ensure that no two products will have the same address. Therefore, the blocks of MAC addresses are normally stored in the servers and assigned to specific product IDs upon request. This also allows the MES server to keep a record of the product ID and their assigned MAC address.

Another example of information download based on product ID will be product firmware. For product sites building multiple versions of the product, it is important to ensure that the correct firmware be programmed onto the product.

The manufacturing execution system controls the shop floor operation of a manufacturing facility. Therefore it is commonly referred to as the shopfloor control system or shopfloor server.

Connections between Shopfloor Server and Clients

There is no standard protocol governing the communications between the production line equipment and the Shopfloor server. Every station on the production line has got its own function and data to upload. There are also different shopfloor software packages available in the market, each with their own method of transmitting information in and out of the production line. As such, there is no single universal application that can adapt to all equipment. Equipment will need to have a customized software application to handle the communications between the equipment software and the shopfloor server. This software application is known as the shopfloor client.

The shopfloor client works as the middle man between the equipment software and the shopfloor server. Therefore, it needs to handle two communication protocols; one between equipment software and the client and another between the client and the shopfloor server.

The communication of the shopfloor client to the shopfloor server will differ from case to case depending on the type of shopfloor software used. It will require detailed understanding of the shopfloor server in order to be able to develop a client application to handle the communication. Similarly for every station on the production line, the required information to transmit and receive is also different.

The physical link between the production stations and the shopfloor server is typically over local area network (LAN) given the fact that the server will be managing a significant number of stations located all over the manufacturing facility.

Equipment that links to the shopfloor server will require a shopfloor client application to handle the communication. The shopfloor client normally resides within the equipment itself and runs as a background process to monitor and transfer data between itself and the Shopfloor server