Industry News, Trends and Technology, and Standards Updates

GEM: Meeting Future Needs by Building on the Stability of the Past

Posted by David Francis: Director of Product Management on Jan 8, 2020 11:00:00 AM

Mechanic-working-on-a-diesel-filter-close-up-629x419-CopyAs a young boy, I liked to work on the family car with my dad. He taught me how to change the oil, check the spark plugs, replace the shock absorbers, adjust the timing and lots of other tasks that were common on older cars. I remember the first time he let me use the socket wrench. I thought it was the greatest tool ever invented. I could loosen bolts, then moving a small switch into a different position, the same wrench could now tighten bolts. It is a very versatile tool, one I still make sure to have handy to this day. 

I appreciate having well-designed tools available that can be used in a variety of situations. In my career, these tools have sometimes been software tools. I have spent a lot of my career working with equipment connectivity standards and seeing the benefits of having process equipment connected to a factory control system. Whether it is for full equipment control, or just to monitor and gather data from the equipment, having a robust connection to equipment is valuable.  

When I first started connecting equipment to factory control systems, the GEM standard had not been finalized. There was a lot of variability in the SECS message implementations available from the different equipment vendors. I was almost always able to get the equipment connected to the factory system, but generally each connection was custom to that equipment vendor and equipment type. This meant that each connection took far too much time to complete and made supporting different equipment very difficult. 

Once the GEM standards were finalized and adopted, there was now a versatile way to provide consistency and reusability across equipment types and across equipment vendors. Connecting to different types of equipment was principally a configuration task instead of a custom coding task.  

In addition, industry standard compliance test tools were developed to ensure compliance with the GEM standards and harden the implementations for reliable production use. This increased reliability helped drive the adoption and implementation of GEM in the global semiconductor front-end manufacturing industry. As a result, GEM has become a well-established reliable communication standard that is widely used and accepted.  

As other segments of the semiconductor and related electronics manufacturing markets have looked to connect equipment to their factory control systems, many have evaluated GEM and other communication standards to provide this functionality. In some cases, GEM was considered too old, too complex, or not a good fit. But, like the versatile socket wrench, many industry segments have seen the value of the stability and proven nature of GEM. They found that the socket wrench (GEM) was the right toolthey just needed a different sized socket (industry-specific guidance) to fit their needs. Let’s look at a few examples.  

SEMI PV2 

large solar farm in England producing electricityIn 2007, when the photovoltaic industry wanted to increase manufacturing efficiencies and reduce costs, they looked to implement industry-wide standards. They formed the Photovoltaic Equipment Interface Specification Task Force to define the interface between the factory control system and the equipment. 

The task force created two working sub-teams to evaluate existing solutions and the requirements of the industry. Several existing solutions such as SECS/GEM, EDA, OPC-UA, and XML were evaluated based on functionality, reliability, extendibility, and the ability to be integrated into different environments. The conclusion of both teams was to build on the SEMI GEM (E30) standard.  

The socket wrench (GEM) was the right tool, and a new socket (SEMI PV2) provided the required fit for their equipment and industry. 

HB-LED 

In 2010, when the high-brightness light-emitting diode (HB-LED) industry started their search for connectivity standards. They needed something that would allow low-cost, common hardware and software interfaces, and other means to enable HB-LED factories to effectively utilize multiple equipment types from multiple vendors in a highly automated manufacturing environment. 

This search found that the best course was to leverage the functionality, reliability, and extendibility of GEM. The SEMI HB4: Specification of Communication Interfaces for High-Brightness LED Manufacturing Equipment (HB-LED ECI) defines the behavior of HB-LED equipment and is based on the SEMI E30 (GEM) standard.  

Again, the socket wrench (GEM) was the right tool. What they needed was a socket (HB4) that would meet the needs of their industry. 

PCBECI 

In February 2019, the Taiwan Printed Circuit Association (TPCA) initiated an activity seeking to boost network connectivity of PCB equipment and help PCB makers implement smart manufacturing practices in the industry.  

The result of this effort was the publication in August of 2019 of the SEMI A3: Specification for Printed Circuit Board Equipment Communication Interfaces (PCBECI). This is a robust and comprehensive shop-floor communication standard that specifies the detailed, bidirectional communications needed to improve productivity and reduce the costs to develop equipment interfaces for PCB manufacturing. The SEMI A3 (PCBECI) standard is based on the SEMI E30 (GEM) standard. 

Yet again, the socket wrench (GEM) was the right tool and all that was needed was a socket for their specific needs (PCBECI).  

It is understandable to think of GEM as an old and complex standard. It has been around for years and can be difficult to understand. However, it has continued to be reviewed and updated as manufacturing needs have changed. As different market segments have looked for equipment communication standards to meet their specific needs, several have found that the functionality, reliability, extendibility and the ability to be integrated into different environments provided by GEM was the right tool. All that was needed were some companion specifications related to GEM to provide a better fit for their requirements. 

Topics: Industry Standards, SECS/GEM, Smart Manufacturing/Industry 4.0

Why implement a SECS GEM driver?

Posted by Brian Rubow: Director of Solutions Engineering on Dec 12, 2019 2:15:00 PM

A SECS GEM driver can be looked at from a factory or equipment supplier perspective. I will discuss both of them in that order.

Factory Perspective

A little background:

semiconductor-factory-1

From a factory perspective, a SECS GEM driver is the host software that talks to an equipment’s GEM interface. It allows the factory to take advantage of the features implemented in each equipment’s GEM interface. However, what the factory can do with an equipment’s GEM interface is also limited by what the equipment supplier has included in that interface. The GEM standard is very flexible and scalable, which accounts for the widespread and growing adoption of GEM technology—it can be adapted to any manufacturing equipment and market segment.

It is possible to implement features in a GEM interface. But this also means that just having a GEM interface on the equipment does not ensure that it has been correctly designed to meet the factory’s expectations. An equipment supplier’s poor implementation of GEM can frustrate a factory’s plans for Smart Manufacturing by not providing features that the factory expects that could have been implemented. The tendency of most equipment suppliers is to implement the absolute minimum functionality in a GEM interface to save money. Therefore, it is the responsibility of the factory during equipment acceptance to evaluate the GEM interface to make sure that it is robust and has the full set of required features. The factory must have a clear vision of its needs both initially and later as its Smart Manufacturing goals are realized. It is not unusual for a factory to request an upgrade to an equipment’s GEM interface with more features, but these modifications usually come at a cost.

Although a factory’s SECS GEM driver must be adaptable to different suppliers’ GEM implementations, it only needs to support the specific features that the factory uses. For example, if the factory is only concerned about alarm and event report notification, then it does not need to support the messages for recipe management, remote control or trace data collection. As such, the investment in a SECS GEM driver is proportional to the number of GRM features that are utilized. However, the SECS GEM driver should also support variations in alarm and collection event implementations, because each equipment type will support a unique set of alarms and a unique set of collection events with unique data variable for event reports. Moreover, from equipment type to equipment type, the same collection ID might have different meanings. The SECS GEM driver therefore needs an ability to adapt by having a method to characterize the GEM implementation (such as a list of available collection events) and the ability to map a general capability to the actual implementation (such as “material arrived” = collection event ID 5).

So why would a factory want to use SECS GEM technology?

factory-alan-1In order to reach the goals of Industry 4.0 and Smart Manufacturing, factories must be able to monitor and control manufacturing equipment remotely. Therefore the equipment must have a software interface to provide this functionality and the factory must be able to access and use this interface.

Factories could let the equipment suppliers choose their own implementation technologies for this kind of capability, but as a result, different suppliers might take a different approach for every equipment type. This would be tremendously expensive and resource intensive. It is far better to standardize on one or two technologies, and ideally, one that is proven to work and known to have all of the necessary features. This allows the factory to achieve its goals with minimum investment, focusing instead on using the equipment interface in creative ways to improve manufacturing.

SECS GEM is the most proven technology already widely used across the globe and supported by the most sophisticated and automated industry in the world; semiconductor manufacturing. It is also widely adopted several other industries, making it a safe choice. The range of production applications supported by SECS GEM data collection include productivity monitoring, statistical and feedback/feedforward process control, recipe selection and execution tracking, fault detection and classification, predictive maintenance, reliability tracking, and many more. By contrast, alternatives to SECS GEM have so far been demonstrated to be incomplete or immature solutions. 

What specifically can you do with the SECS GEM technology?

  1. Collection Events: Be notified when things happen at the equipment, such as when processing or inspection begins and completes, or when a particular step in a recipe is reached.
  2. Collection Event Reports: Collect data with collection events. The host chooses what data it wants to receive. For example, track the ID of material arriving and departing from the equipment, or components placed on a board.
  3. Alarms: Be notified when bad or dangerous things are detected, receive a text description of the alarm condition, and when the issue is cleared.
  4. Trace Data Collection: Tell the equipment to report status information (software and/or hardware data) at a specific interval. For example, track digital and/or analog sensors during processing at 10 Hz frequency.
  5. Recipes: Upload, download, delete and select recipes as desired, whether in ASCII or binary formats. Make sure that the right recipe is run at the right time to eliminate misprocessing and minimize scrap. Track when someone changes a recipe.
  6. Remote Commands: Control the equipment, such as when to start, stop, pause, resume and abort. Custom commands, such as calibrate, skip or anything else can be supported.
  7. Equipment Constants: Configure and track the equipment configuration settings remotely.
  8. Terminal Services: Interact with the equipment operator remotely or provide instructions for the operator.
  9. Extensions: There are numerous extensions to GEM that can be supported but are not yet form requirements. For example, implement wafer or strip maps from E142 to provide and report details about material in XML format.

Equipment Supplier Perspective

AdobeStock_12291008-1

From an equipment supplier’s perspective, a SECS GEM driver is the software used to implement GEM technology on the equipment. In other words, the software to create a GEM interface. The equipment-side software requirements are inherently more complex that the host SECS GEM driver. This is because the equipment-side features are precisely defined by the GEM standard and should be implemented to the fullest extent possible. By contrast, the host can really do whatever it wants, so a limited implementation may be sufficient. In an ideal situation, the equipment supplier will implement just enough features in its GEM interface to satisfy all of its customers and therefore ship an identical GEM interface to all its customers. It is up to the equipment supplier to decide what GEM features to implement and how to adapt them for a particular type of equipment, but the factory should provide clear expectations about its planned use of the interface. It is also the factory’s responsibility to qualify the GEM interface during equipment acceptance. Note that it is not uncommon for factories to withhold partial equipment payment until the GEM interface has also passed its own acceptance.

Some equipment suppliers include the GEM driver as a standard feature on all equipment. This is ideal because it makes the GEM interface much easier to support and distribute. Some equipment suppliers only install GEM when it is specifically purchased. This often results in installation problems because the field technicians may or may not be knowledgeable enough or specifically trained to do this correctly. Other equipment suppliers include the GEM driver on all equipment, but only enable it when the feature has been purchased. This is better than attempting GEM interface installation after equipment delivery because the GEM interface can often be enabled with a simple equipment configuration setting.

Here are some key reasons for implementing a SECS GEM driver:

1. “One ring to rule them all”

By implementing a GEM interface, an equipment supplier can avoid having to implement multiple interfaces. Because GEM is the most feature complete option, the it should be implemented first and Thoroughly integrated with the equipment control and user interface software. If other protocols must be supported, they can usually be mapped onto the GEM capabilities or a separate external system because they only include a subset of GEM functionality.

2. Equipment Supplier Application Software

If the GEM implementation includes support for multiple host connections, then the GEM interface can be used by the equipment supplier itself for many applications. For example, an equipment supplier can develop a software package that monitors and controls their specific equipment at a factory. This can run simultaneously and independently while the factory GEM host software is connected. Many factories are willing to buy applications from the equipment supplier that enhance the productivity of the equipment they have purchased. As an example, equipment suppliers are better equipped to develop predictive maintenance applications that determine when parts are approaching failure and need replacement. These applications can save the factory time and money by avoiding unscheduled downtime. Other applications can also be developed by equipment suppliers to analyze and optimize equipment execution.

3. Competitive Advantage

A well implemented GEM interface can differentiate a supplier’s equipment from that of its competitors. Factories are beginning to recognize the value in controlling and monitoring equipment remotely, and know that a poor GEM interface contributes nothing to a factory’s Smart Manufacturing initiatives. A GEM interface that goes the extra mile to be truly useful empowers the factory to excel at Smart Manufacturing and to be far more productive. Selling equipment in today’s market without a GEM interface is like selling a television without a remote. On the other hand, providing a fully featured GEM interface is like selling a smart television.

Final Words

Experts on GEM technology are available all over world. Because GEM is a mature industry standard and well defined, it can be implemented by anyone in a range of different programming languages and operating systems. however, to save time I recommend using a commercially available product rather than developing the complete GEM interface from scratch. This can save massive amounts of time and effort, and ensures the quality of the resulting implementation.

To speak with a Cimetrix GEM expert, or to find out more about our GEM software products, you can schedule a meeting by clicking the link below.

Ask an Expert

Topics: Industry Standards, SECS/GEM, Semiconductor Industry, Smart Manufacturing/Industry 4.0

Resources Round-up: Presentations

Posted by Kimberly Daich; Director of Marketing on Oct 3, 2019 11:16:00 AM

Resource Center-1The Cimetrix Resource Center is a great way to familiarize yourself with standards within the industry as well as find out about new and exciting technologies. 

Our resource center features information about equipment connectivity and control, data gathering, GEM (SECS/GEM)EDA/Interface A, and more. These standards are among the key enabling technologies for the Smart Manufacturing and Industry 4.0 global initiatives that are having a major impact on the electronics assembly, semiconductor, SMT and other industries. Manufacturers and their equipment suppliers must be able to connect equipment and other data sources, gather and analyze data in real time, and optimize production through a wide variety of applications.

The many presentations featured in our resource center provide in-depth coverage from Cimetrix expert's presentations at many different conferences and expos around the world. Some of our most popular presentations are below.

Be sure to stop by our Resource Center any time or download the presentations directly from the links in this posting.

Resources

Topics: Industry Standards, SECS/GEM, EDA/Interface A, Doing Business with Cimetrix, Programming Tools, Photovoltaic/PV Standards, Smart Manufacturing/Industry 4.0

Resources Round-up: Videos

Posted by Kimberly Daich; Director of Marketing on Aug 3, 2019 1:28:00 PM

Resource Center-1The Cimetrix Resource Center is a great way to familiarize yourself with standards within the industry as well as find out about new and exciting technologies.

Our resource center features information about equipment connectivity and control, data gathering, GEM (SECS/GEM)EDA/Interface A, and more. These standards are among the key enabling technologies for the Smart Manufacturing and Industry 4.0 global initiatives that are having a major impact on the electronics assembly, semiconductor, SMT and other industries. Manufacturers and their equipment suppliers must be able to connect equipment and other data sources, gather and analyze data in real time, and optimize production through a wide variety of applications. The videos and video series featured in our resource center provide in-depth coverage of some of these concepts.  Some of our featured videos are below.

Be sure to stop by our Resource Center any time or watch the videos directly from the links in this posting.

Resources

Topics: Industry Standards, SECS/GEM, EDA/Interface A, Doing Business with Cimetrix, Programming Tools, Photovoltaic/PV Standards, Smart Manufacturing/Industry 4.0

Standards Made Simple #1 – GEM (Generic Equipment Model)

Posted by Ranjan Chatterjee on Jul 10, 2019 10:54:00 AM

Ranjan-Chatterjee-2017-industriesIn this our first standard overview, we look at GEM. At its history, its application and its suitability for use in the smart factories of today and the future.

Overview

The GEM standard defines a software interface that runs on manufacturing equipment. Factories use the GEM interface to remotely monitor and control equipment. The GEM interface serves as a broker between the factory host software (host) and the manufacturing equipment’s software. Because the GEM standard is an open standard, anyone can develop GEM capable host or equipment software.

The GEM standard is published and maintained by the international standards organization SEMI based in Milpitas, CA, USA. SEMI uses the standard designation “E30” to identify the GEM standard with the publication month and year appended as four numbers to designate a specific version. For example, E30-0418 identifies the version of the GEM standard published in April of 2018.

The GEM/SECS-II standards are protocol independent. Today, there are two protocols defined by SEMI: SECS-I (E4) for serial communication and HSMS (E37) for network communication. SECS stands for ‘SEMI Equipment Communications Standard’ and HSMS stands for ‘High-Speed SECS Message Services’.

Not surprisingly, most systems today are using the HSMS. HSMS does not specify the Physical Layer. Any physical layer supported by TCP/IP can be used, but typically everyone uses an Ethernet network interface controller (NIC) with an RJ45 port. When using the SECS-I standard, the messages size is limited to 7,995,148 bytes (about 8MB).

The GEM standard is built on top of SEMI standard SECS-II (E5). The SECS-II standard defines a generic message layer to transmit any data structure and defines a set of standard messages each with a specific ID, purpose and format.

History and Adoption

GEM was developed by the semiconductor industry to allow fabricators to connect and manage multiple machines in billion dollar facilities all around the world.

GEM is the adopted technology by factories worldwide because it is mature and supports all the features required now and expected in the future. GEM allows the same technology and software to be used to integrate multiple equipment and process types, independent of supplier.

The GEM standard is used in numerous manufacturing industries across the world, including semiconductor front end, semiconductor back end, photovoltaic, electronics assembly, surface mount technology (SMT), high brightness LED, flat panel display (FPD), printed circuit board (PCB) and small parts assembly. The adaptability of the GEM standard allows it to be applied to just about any manufacturing industry.

All semiconductor manufacturing companies including Intel, IBM, TSMC, UMC, Samsung, Global Foundries, Qualcomm, Micron, etc., currently use the GEM standard on all manufacturing equipment and have for many years. This includes 300mm, 200mm and 150mm wafer production.

GEM was successful enough early on that SEMI developed and currently uses several additional factory automation standards based on GEM technology. These additional standards are referred to as the GEM 300 standards, named because of their widespread adoption by the factories dedicated to the manufacturing of 300mm wafers.

In 2008, the photovoltaic (solar cell) industry officially adopted GEM with SEMI standard PV2 (Guide for PV Equipment Communication Interfaces) which directly references and requires an implementation of the GEM standard. In 2013, high-brightness LED industry created a similar SEMI standard HB4 (Specification of Communication Interfaces for High Brightness LED Manufacturing Equipment). Recently, the printed circuit board association has followed in the same path with ballot 6263 (Specification for Printed Circuit Board Equipment Communication Interfaces). All three standards similarly define implementations of the SEMI standard that increase GEM’s plug-and-play and mandate only a subset of GEM functionality to facilitate GEM development on both the equipment and host-side.

Several additional SEMI standards have been created over the years to enhance GEM implementations and are applicable to any industry and equipment. E116, Specification for Equipment Performance Tracking, defines a method to measure equipment utilization as well as the major components within the equipment. E157, Specification for Module Process Tracking, allows an equipment to report the progress of recipe steps while processing. E172, Specification for SECS Equipment Data Dictionary, defines an XML schema for documenting the features implementing a GEM interface. E173, Specification for XML SECS-II Message Notation, defines an XML schema for logging and documenting messages.

Flexibility and Scalability

GEM requirements are divided into two groups; Fundamental Requirements and Additional Capabilities. Any equipment that implements GEM is expected to support all the Fundamental Requirements. Additional Capabilities are optional and therefore are only implemented when applicable. This makes the GEM standard inherently flexible so that both a simple device and a complex equipment can implement GEM.

GEM easily and inherently scales to the complexity of any system. A simple device need only implement the minimum functionality to serve its purpose. Whereas complex equipment can implement a fully featured GEM interface to allow the factory to fully monitor and control its complex functionality. GEM also allows multiple host applications to connect to an equipment.

The requirements in that the GEM standard only apply to the equipment and not the host. This means that equipment behavior is predictable, but the host can be creative and selective choosing to use whichever features from the equipment’s GEM interface to attain it goals.

Our Seven Point Checklist

Remember our simple seven-point checklist for connectivity from our original article:

  • Event Notification – real-time notification of activity & events
  • Alarm Notification – real-time notification of alarms & faults
  • Data Variable Collection – real-time data, parameters, variables & settings
  • Recipe Management – process program download, upload, change
  • Remote Control – start, stop, cycle stop, custom commands
  • Adjust Settings – change equipment settings & parameters
  • Operator Interface – send & receive messages to/from operator

Put simply GEM succeeds in each of these areas and you can find more detail by downloading our white paper or watching the videos on our website.

Conclusion

If you’re looking for a tried and tested standard that can be applied to any smart manufacturing ecosystem, no matter how large, it’s hard to beat GEM. The semiconductor industry is one of the most demanding and expensive industries in the world and they have done the work for everyone else at great cost and over many years. Industries like PCB fabrication are adopting this standard rather than developing their own for good reason, they need something that can be applied quickly, reliably, economically and at scale.

Forgive the pun but, we believe GEM is the gold standard for standards. We’ve been working with it successfully for decades in the semiconductors industry and more recently in PCB and SMT facilities. In some cases, we have deployed GEM at the request of OEM customers to drive greater control and traceability in their supply chain.

GEM White Paper

This blog was first posted on EMSNow.com.

Topics: Industry Standards, SECS/GEM, Smart Manufacturing/Industry 4.0

Resources Round-up: Ebooks

Posted by Kimberly Daich; Director of Marketing on Jun 19, 2019 11:23:00 AM

Resource Center-1The Cimetrix Resource Center is a great tool for anyone who wants to learn more about industry standards including Equipment Connectivity and Control, data gathering, GEM (SECS/GEM)EDA/Interface A, and more. These standards are among the key enabling technologies for the Smart Manufacturing and Industry 4.0 global initiatives that are having a major impact on many industries. Manufacturers and their equipment suppliers must be able to connect equipment and other data sources, gather and analyze data in real time, and optimize production through a wide variety of applications. The free eBooks listed below provide in-depth coverage of the some of these concepts.  They have been written by technical experts who have participated in and led the standards development processes for more than two decades.

Be sure to stop by our Resource Center any time or download the white papers directly from the links in this posting.

Resources

Topics: Industry Standards, SECS/GEM, EDA/Interface A, Doing Business with Cimetrix, Programming Tools, Photovoltaic/PV Standards, Smart Manufacturing/Industry 4.0

Do you need help with GEM Testing?

Posted by David Francis: Director of Product Management on May 22, 2019 11:21:00 AM

A few years ago, I went through the process of building a new house. It was exciting to work with the architect to design the house and imagine what the finished product was going to be like. The architect created a 40-page set of drawings detailing all the components that would go into the house, like the electrical, plumbing and flooring. I thought everything was covered. I was a little surprised when things didn’t go exactly as detailed in the drawings. There were exceptions! However, having the detailed drawings made it easier to identify where things went wrong and helped clarify what needed to be done to correct the problems.EquipmentTest-Software-Control

Communication standards like GEM are like a set of architectural drawings for how to connect equipment to factory control systems. They define what needs to be communicated, how the communication needs to take place and provide a great roadmap for getting there. But like building a new house, there are usually a few surprises along the way. A standard, consistent way of testing the interface that can be used by both the factory and equipment manufacturer, greatly reduces the unknown and simplifies the process.

The new Cimetrix EquipmentTest™ product is the fastest way to achieve GEM Compliance for factory acceptance testing of new equipment. Whether you are an equipment manufacturer or factory, making sure the equipment interface is GEM compliant is critical. Having an easy-to-use testing solution to determine if the equipment is GEM compliant is critical.

There are two versions of EquipmentTest depending on your needs. The EqupmentTest Basic version is ideal for both Smart factories and equipment manufacturers to quickly and easily test the basic capabilities of an equipment’s GEM interface. EquipmentTest Basic includes a simple testing scenario, called a plugin, to evaluate the equipment’s ability to connect to a GEM host and communicate events, data and alarms. This version also includes the ability to send/receive individual messages to/from the equipment for discovery or diagnostic purposes. With the messaging functionality, you can also create macros to send and receive groups of messages.

For more complex testing, there is the EquipmentTest Pro version. In addition to all the features of the EquipmentTest Basic version, EquipmentTest Pro includes a full, rigorous GEM compliance testing plug-in and an operational GEM compliance testing plugin. The Pro version includes development tools to allow you to create your own custom tests/plug-ins using .NET languages. The GEM compliance plugin generates a GEM compliance statement that shows the areas and level of compliance to the GEM standards. There are also other tools only available in the EquipmentTest Pro version that allow you easily test and interact with the GEM functionality on the equipment.

As with all our products, Cimetrix supports the industry connectivity standards so you never have to wonder if your equipment is keeping up with the rest of the industry.

You can purchase either version of EquipmentTest directly from our website and download the software immediately. You will need to provide a valid Mac ID and email address for licensing purposes. You will receive your license agreement no more than 48 hours after purchase. Be sure to learn more and get your EquipmentTest download today!

Buy EquipmentTest Today

Topics: Industry Standards, SECS/GEM, Smart Manufacturing/Industry 4.0, Cimetrix Products

Multiple GEM Connections on Manufacturing Equipment

Posted by Brian Rubow: Director of Solutions Engineering on Apr 10, 2019 12:47:00 PM

The GEM standard is often incorrectly perceived as a single-connection protocol for manufacturing equipment. A single connection means that only one software product can use the GEM interface at one time. Many manufacturing equipment that support the GEM standard only have the ability for one connection. However, this limitation is set only in ignorance, by tradition, and to satisfy the common manufacturing system architecture. 

The truth is that the GEM standard simply does not discuss additional connections--meaning that additional connections are neither required nor prohibited. Not only is it possible for an equipment to support multiple concurrent GEM interfaces, this is becoming more and more common. If each supported GEM connection is point to point and complies with the GEM standard, this is certainly allowed. However, each connection should be completely independent of other GEM connections and still comply with the GEM requirements. Implementing multiple connections raises several questions. 

What does it mean for each GEM connection to be independent?

It means that each GEM host operates completely independently, as if the other GEM host connections were not present. Here is a more specific list of attributes that define “completely independent”:

  • The Communication state model is independent. Each can establish and disconnect independently from the other host packages.
  • The Control state model is independent. Each can be set up as local or remote as needed. 
  • Collection event report dynamic configuration is completely independent. Each host defines a unique set of reports and subscribes to a unique set of collection events. Even so, if two GEM host connections create identical reports and link them to the same collection event, then both should receive identical data. 
  • Each host subscribes to a unique set of alarms. 
  • Each host can query status information independently of any another.
  • Each host can choose to enable or disable Spooling and configure it as desired.
  • Each host can set up its own trace data collection.
  • Each host only receives messages based on its subscriptions.
  • Each host only sees reply messages to its primary messages.

Are you talking about HSMS-GS? 

No. HSMS-GS means implementing SEMI Standard E37.2, High Speed Message Service – General Session, an inactive SEMI standard. This standard, which never gained much industry traction, opens a single port through which any number of clients can connect. In contrast, I am talking about supporting multiple implementations of E37.1, High Speed Message Service – Single Session (HSMS-SS) where each connection uses a unique port number. Nearly all GEM interfaces today use the HSMS-SS protocol. 

What are the advantages of having multiple GEM connections in a single GEM interface? 

This opens the door for many useful applications. Here are three example configurations, and of course, all of them could be accomplished at the same time. 

  1. A factory can set up multiple host software packages at the same time to connect to the same equipment’s GEM interface, without any knowledge of or interference with each other. With only a single connection, a factory wanting to do the same thing has to implement some sort of GEM host broker to funnel the different GEM host package communications into a single GEM connection… a technically challenging feat. 01_GEMHost_v3
  2. If an equipment supplier wants to create an application designed specifically for its equipment running in a factory, they can use one of the GEM connections. They don’t have to replicate functionality into a custom interface. 02_GEMHost_v3
  3. If one equipment needs to monitor, control, or pass data directly to or from another equipment, this can be done using one of the GEM connections without interference to the factory GEM connection. This is relatively simple to set up. Sometimes this is called horizontal communication. Such communication can also be channeled through a host using the traditional vertical communication use case for a GEM interface. 03_GEMHost_v3

What about safety?

Typically, I would expect factories to set up one and only one connection in the GEM interface to be in the online-remote state and allowed to send remote commands. But this is not an absolute requirement. It is not difficult to imagine applications where execution of remote commands is distributed among multiple applications. For example, an equipment supplier might use one GEM connection to manage periodic recalibration of the equipment based the actual measured performance. 

What are the technical complications? 

There are a few. 

  • Because each connection uses a separate port number, the GEM interface can only support a finite number of connections when using HSMS-SS. 
  • Because multiple connections are not addressed explicitly in the standard, there are not requirements for handling them. For example, GEM requires that operator commands and operator recipe management activity be reported to the host. However, when another connection sends a remote command or downloads a new recipe, there is no requirement to report this. Our CIMConnect product does, but there are no formal requirements to do so. 
  • GEM requires the communication status to be displayed in the GUI, but what about multiple connections? It is not clear what needs to be displayed for multiple hosts. Typically I’ve just displayed the first GEM connection status, but it might be useful to show each connection status and give the operator a chance to control all GEM connections. 
  • Some collection events (and hence data variables), status variables and equipment constants are targeting the behavior of that single connection. This means that in order to implement multiple connections correctly, these connection-specific features must be unique for that connection. For example, consider status variables EventsEnabled and ControlState. The values reported for these two status variables are unique to that connection. This adds some complexity to implementing the GEM interface with multiple connections. Of course, our CIMConnect product implements and handles this already. 

Does each GEM connection have to be identical? 

No, but generally speaking it should be the same. The same set of collection events/data variables, alarms, status variables, and equipment constants should be reported to all connections. However, there are use cases where it might be useful to have some unique collection events and data on one connection. For example, if an equipment supplier uses one GEM connection as a pipeline for a factory host package dedicated to their equipment, they might want to publish some unique data that is for its eyes only. As mentioned above, if two GEM host connection create an identical report, and link it to the same collection event, then both should receive identical data. On the other hand, trace data reports with the same status variables may not need to report identical data, because the values might be sampled independently and at different time intervals. 

How many GEM connections should an equipment support in its GEM interface?

I recommend supporting five connections. Most GEM implementations are just using one connection today, so this opens the door for up to four more connections. This enables an equipment to handle most situations without the need to be reconfigured later at the factory. In CIMConnect, the overhead for having five connections is quite minimal, and virtually nothing if they are not used. 

What should the communication settings be? 

You should definitely set up the equipment as passive. This puts all of the configuration on the host side. The device ID can be the same for all connections, where 0, 1, or 32767 is best. 

How do I turn on multiple GEM connections in CIMConnect?

Since our CIMConnect product inherently supports multiple GEM connections, Cimetrix customers really only have to configure the setup file. Our CIMConnect GEM product was originally designed with multiple GEM connections in mind; therefore it is native and intuitive, with virtually no extra programming required unless you count the additional work in the operator interface. In the setup file, just create the five [CONNECTIONX] sections initially, and then set up a connection-specific VARIABLES and EVENTS section for each of the five connections. 

Alternative Approaches?

One alternative approach is to look at the SEMI Equipment Data Acquisition (EDA) standards. An EDA interface is inherently only for data collection and has multiple client access built into the standard as a fundamental requirement. The semiconductor front end device manufacturers have successful embraced this technology in addition to the GEM standard. The GEM interface is used by the Manufacturing Execution System for command and control of the equipment, while the EDA interface is used for every other application. 

Final Thoughts

My recommendation is that everyone, especially Cimetrix CIMConnect customers, take a look at their GEM interface and make sure that you are doing a good job implementing multiple host connections. CIMConnect makes this extremely easy. And let your customers know that you have this feature so that they can take advantage of it. 

You can learn more about the GEM standard any time on our website.

GEM Standard

Topics: Industry Standards, SECS/GEM, Smart Manufacturing/Industry 4.0, Cimetrix Products

Resources Round-up: White Papers

Posted by Kimberly Daich; Director of Marketing on Mar 26, 2019 11:15:00 AM

Resource Center-1The Cimetrix Resource Center is a great tool for anyone who wants to learn more about industry standards including GEM (SECS/GEM), GEM300, EDA/Interface A, and more. These standards are among the key enabling technologies for the Smart Manufacturing and Industry 4.0 global initiatives that are having a major impact on many industries. Manufacturers and their equipment suppliers must be able to connect equipment and other data sources, gather and analyze data in real time, and optimize production through a wide variety of applications. The free white papers listed below provide in-depth coverage of the most broadly used equipment connectivity standards. They have been written by technical experts who have participated in and led the standards development process for more than two decades.

Be sure to stop by our Resource Center any time or download the white papers directly from the links in this posting.

Resources

Topics: Industry Standards, SECS/GEM, EDA/Interface A, Doing Business with Cimetrix, Programming Tools, Photovoltaic/PV Standards, Smart Manufacturing/Industry 4.0

Overview of the GEM Standard: Video Series Part Four of Five

Posted by Kimberly Daich; Director of Marketing on Feb 26, 2019 11:32:00 AM

The fourth part of our Overview of the GEM Standard Video series is here! New call-to-action

In this video, Brian Rubow gives a description and dives a little deeper on some of the most important GEM features including the following:

  • Self-Description
  • Alarms
  • Remote Control
  • Equipment Constants
  • Recipe Management
  • Material Movement
  • Terminal Services
  • Clock
  • Spooling

View the entire series today!

Topics: Industry Standards, SECS/GEM, SECS/GEM Features & Benefits Series