Industry News, Trends and Technology, and Standards Updates

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

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

Posted by Kimberly Daich; Director of Marketing on Jan 3, 2019 11:22:00 AM

Join Brian Rubow for the third video in our five-part video series which covers another of the core features of GEM.

New call-to-action

One of the core features for monitoring equipment is the GEM Collection Event Notification. Every equipment will publish a set of collection events. These report in real-time when things are happening at the equipment level that a factory may want to monitor. The equipment will document a set of events that are aviable at the factory level, and the host can choose which ones they want to subscribe to.

View the entire series today!

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

A Look Back At Our Year As 2018 Comes To A Close

Posted by Kimberly Daich; Director of Marketing on Dec 19, 2018 11:47:00 AM

number-2018-wooden-cube-blockIt's getting close to the end of 2018 and we thought it was a good time to look back over our year and think about the many things Cimetrix has done. We are really proud of our team, which spans the globe, their hard work and accomplishments throughout the year. 

Tradeshows and Events

Our team attended, presented and exhibited at more than 25 events this year. These events covered the U.S., Europe, China, Taiwan, Japan, Korea, Southeast Asia and more. SEMICON West was a flagship event for us, as we took a large team to support two distinct booth areas. These included SEMI’s inaugural Smart Manufacturing Pavilion, where both Alan Weber and Ranjan Chatterjee spoke. You can review this event in the following three blog posts:

SEMICON West Pre-show
Alan Weber's Smart Manufacturing Pavilion speech
Brian Rubow's SEMICON West SEMI Standards meetings wrap-up


SECS/GEM Series

One of our longest series was also one of our most popular ever! It covers the major features and benefits of the GEM standard. Each post was written by one of our engineers who is an expert in the topic. You can review the entire series or select a particular topic you are most interested in learning more about.

SECS/GEM Series


International Offices

Cimetrix has been extremely active this year, and one of the most exciting areas was the opening and/or expansion of several offices in Asia. In February we announced the opening of Shanghai, China office. This blog post is one of several bi-lingual posts we published during 2018 and was one of our most viewed. Learn more about our efforts in China now!

Cimetrix International, Inc., China; 矽美科国际有限公司,中国


Cimetrix Team Members

We have run a Meet Our Team series for over a year, and this is consistently one of our most viewed blog series. Everyone loves getting to know the faces behind the company, and we likewise enjoy introducing our team to the world. You can see all of our Meet Our Team posts at the link below and be sure to stay tuned, because our team is growing, and we will continue to introduce them in this series!

Meet Our Team blog series


And finally, we can't have a year-end wrap-up without our most popular blog of the year...

Gigafab Minute

In October of this year, Alan Weber, our Cimetrix V.P. of New Product Innovations introduced the world to the Gigafab Minute infographic. This blog was picked up and re-posted by SEMI and passed around by some of the most influential leaders in the semiconductor industry. If you haven't seen it yet, we'd encourage you to take a few minutes to read it and leave us your comments!

The Gigafab Minute and SEMI Standards: A Modern Miracle

Take a chance to peruse our posts and remember, you can always stay up-to-date by subscribing to our blog! 

Subscribe Today

Topics: SECS/GEM, Doing Business with Cimetrix, Cimetrix Company Culture, Events, Smart Manufacturing/Industry 4.0

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

Posted by Kimberly Daich; Director of Marketing on Nov 28, 2018 11:15:00 AM

The second video in our Overview of the GEM Standard video series goes into a little more detail on the GEM standard functionality. 

Overview of Gem part 2 of 5

The GEM standard is broken down into two sets of functionality. One is the fundamental requirements.  These are the things that everyone that uses GEM should implement. It gives some of the basic funtionality you want in every equipment and every device that has a GEM interface. Then there are a number of additional capabilities, meaning you can be GEM compliant without using them, but they are available when needed. 

The GEM standard is extremely efficient, with messages that are always transmitted in a binary format, which is much smaller than ASCII based protocols. Among the benefits of this is that the network bandwidth is not wasted. 

To find out even more, be sure to see the second part of our series today! 

Topics: Industry Standards, SECS/GEM

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

Posted by Kimberly Daich; Director of Marketing on Oct 31, 2018 12:08:00 PM

What is a GEM Interface? What are some of the key features of the GEM SEMI Standard? What does the GEM standard have to do with Smart Manufacturing? Brian Rubow, the Cimetrix Director of Solutions Engineering, conducts a five-part video series that covers the complete GEM standard. In this Part One of the series, he covers some of the main questions that are often asked of manufacturing industries looking into GEM for the first time. 

New call-to-action

Brian begins the video by answering the question, "What is a GEM Interface". He follows up by addressing the related SEMI standards, including SECS-II and HSMS. 

The GEM standard is feature complete.and includes the following:

  • Event Notification
  • Alarm Notification
  • Data variable collection
  • Recipe Management
  • Remote Control
  • Adjustment Settings
  • Operator Interface

GEM is the proven and mature equipment communication standard used by the front-end semiconductor industry for a number of years and has been adopted by a number of other industries because of it's effectiveness. 

View the entire series today!

 

Topics: Industry Standards, SECS/GEM

SECS/GEM Series: GEM Control State

Posted by Mark Bennett; Client Support Engineer on Oct 11, 2018 10:59:00 AM

What is GEM Control State?

The GEM Control State is one of the fundamental E30 GEM requirements. It defines the level of cooperation between the host and equipment and specifies how the operator may interact at the different levels of host control.

In a semiconductor factory, the host or operator may be in control of equipment processing. Having both sides in control of the equipment at the same time poses problems. When one side is in control of the equipment, the other side should be limited in the operations it can perform. For example, if an operator pauses processing, the host should not be allowed to send commands to resume processing or to start a new job. The GEM Control State is provided to prevent these types of issues from occurring.

SEMI E30 GEM Control State ModelFigure 1: SEMI E30 GEM Control State Model

How does the Control State work?

The Control State provides three basic levels of control. Each level describes which operations may be performed by the host and equipment sides.

Remote

  • The host may control the equipment to the fullest extent possible.
  • The equipment may impose limits on the local operator’s ability to control the equipment, but this is not a requirement of the standard. The host must be capable of handling unexpected commands invoked by the operator at the equipment.
  • GEM Remote Commands are used by the host to invoke commands on the equipment.

Local

  • The operator may control the equipment to the full extent possible.
  • The host has full access to information. The host can collect data using other GEM features such as collection events, traces, and status data collection.
  • Limits are placed on how the host can affect equipment operations:
    • Remote commands that initiate processing (e.g. START) or cause physical movement are prohibited. During processing, remote commands that affect processing (STOP, ABORT, PAUSE, RESUME) are also prohibited.
    • Other remote commands that do not initiate processing, cause physical movement, or affect processing may be allowed.
    • During processing, the host is prohibited from modifying any equipment constants that affect that process.
    • Equipment constants that do not affect the currently running process may be changed.
    • All equipment constants are changeable when not processing.

Offline

  • The operator has complete control of the equipment.
  • The host has no control over equipment operations and very limited information gathering capabilities.
  • The only messages that the equipment will accept from the host are:
    • Messages used to establish GEM communication (S1F13/F14).
    • Requests to activate Online Control State (S1F17), but only if the currently active state is Host Offline (transition #11 on the Control State Model).
    • S1F2 “Are You There Response” while the attempting to go Online.
  • The only primary messages that the equipment may send to the host are:
    • Messages used to establish communications (S1F13).
    • S9Fx messages, but only in response to the messages to which the equipment will normally respond to while Offline (i.e., S1F13 and S1F17).
    • S1F1 “Are You There Request” is sent to the host when the “Attempt ON-LINE” sub-state is entered. This message is used to get permission from the host to transition into an Online state (transition #5).
  • No messages are spooled while Offline.

The Control State Model was designed in a way to give the equipment operator more control over the state machine than the host.  This protects the operator from unexpected state changes initiated from the host.

  • The equipment operator can choose which Online sub-state is active through the operator interface. The host side cannot choose which Online sub-state is active.
  • The equipment side can put the Control State Model into an Equipment Offline state (transition #6). When in this state, the host cannot request to go Online.
  • The host side can put the Control State into a Host Offline state (transition #10), but the equipment side could reject this request. When in the Host Offline state, the equipment side can always attempt to go Online by first transitioning into the Equipment Offline state (transition #12) followed by an attempt to go Online (transition #3).

Operator Interface Requirements

The equipment must provide a way of displaying the current Control State to let the operator know who is in control of the equipment.

The equipment must provide a momentary switch to initiate the transition to the Equipment Offline state, and another switch to attempt to go Online from the Equipment Offline state. This may be a hardware switch on the front panel, but is often implemented in software using button controls.

The equipment must provide a discrete two-position switch which the operator may use to indicate the desired Online sub-state (Local or Remote). This may be a hardware switch on the front panel, but is often implemented in software using button controls. If implemented in software, the setting must be saved in non-volatile storage.

Conditional State Transitions

In the Control State Model, transitions #1, #2, #4, and #7 are conditional state transitions. The equipment application must provide a way of configuring which state to transition into. Equipment constants may be used for these configuration settings.

Conditional transitions #1 and #2 determine the initial state of the Control State Model during startup. The configuration that controls these transitions can be set for one of the following states:

  • Online
  • Equipment Offline
  • Attempt Online
  • Host Offline

Conditional transition #4 is used to determine which state to transition into after an equipment attempt to go Online fails. The configuration can be set to one of the following states:

  • Equipment Offline
  • Host Offline

Conditional transition #7 is used to determine which Online sub-state (Local or Remote) should be active when the Control State becomes Online. The configuration can be set to one of the following Online sub-states:

  • Local
  • Remote

Which Messages are used for Control State?

Message ID

Direction

Description

S1F1

Host <- Equipment

This message is sent to the host when the equipment attempts to go Online (in the “Attempt ON-LINE” state). The host grants permission by sending the S1F2 reply message. The host can deny permission by sending S1F0 or allowing the message transaction to time out.

S1F15

Host -> Equipment

The host sends this message to request a transition from “Host Offline” to Online (transition #11).

S1F17

Host -> Equipment

The host sends this message to request a transition from Online to “Host Offline” (transition #10).

 

Click here to read the other articles in our SECS/GEM Features and Benefits series. 

To download a white paper with an introduction to SECS/GEM, Click below:

SECS/GEM White Paper

Topics: SECS/GEM, Smart Manufacturing/Industry 4.0, SECS/GEM Features & Benefits Series

The Gigafab Minute and SEMI Standards: A Modern Miracle

Posted by Alan Weber: Vice President, New Product Innovations on Oct 4, 2018 11:04:00 AM

Gigafab minuteEven for someone who has been in this industry since the days of the TI Datamath 4-function calculator and the TMS1100 4-bit microcontroller (yes, that’s been a LONG time – the movie Grease premiered the same year!), it is sometimes hard to grasp the scope and complexity of what happens in today’s leading-edge semiconductor gigafabs. In fact, the only way to comprehend the enormous volume of transactions that occur is to consider what happens in a single minute – this is illustrated in the infographic we have labeled “The Gigafab Minute.”* 


It’s amazing enough to think that a single factory can start 100,000 wafers every month on their cyclical journey through 1500 process steps… and have 99%+ of them emerge 4 months later to be delivered to packaging houses and then on to waiting customers. It’s quite another to realize that all of this happens continuously (24 x 7) and automatically. TMS1100-TIDatamath-image

“How is this possible?” you ask.

Well, a big part of the solution is the body of SEMI standards which have evolved since the early 80s to keep pace with the ever-changing demands of the industry. From an automation standpoint, many of these standards deal with the communications between manufacturing equipment and the factory information and control systems that are essential for managing these complex, hyper-competitive global enterprises.

A significant characteristic of these standards is that they have been carefully designed to be “additive.” This means that new generations of SEMI’s communications standards do not supplant or obsolete the previous generations, but rather provide new capabilities in an incremental fashion. To appreciate the importance of this in actual practice, consider how the GEM, GEM300, and EDA/Interface A standards support the transactions that occur in a single Gigafab Minute. 

Starting at 1:00 o’clock on the infographic and moving clockwise, you first notice that 2.31 wafers enter the line. Of course, these are actually released in 25-wafer 300mm FOUPs (Front-Opening Unified Pod), but 100K wafers per month translates to 2.31 per minute. Since these factories run continuously, once the line is full, it stays full. And with an average total cycle time of 4 months, this means that there are 400K wafers of WIP (work in process) in the factory at any given time. This number, and the total number of equipment (5000+), drive the rest of the calculations. 

GEM (Generic Equipment Model) – SEMI E30, etc.

The GEM messaging standards were initially defined in the early 90s to support the factory scheduling and dispatching applications that decide what lots should go to what equipment, the automated material handling systems that deliver and pick-up material to/from the equipment accordingly, the recipe management systems that ensure each process step is executed properly, and the MES (Manufacturing Execution System) transactions that maintain the fidelity of the factory system’s “digital twin.” 

Every minute of every day, GEM messages support and chronicle the following activities: 240 process steps are completed (i.e., 240 25-wafer lots are processed), 300 recipes are downloaded along with a set of run-specific adjustable control parameters, and 600 FOUPs are moved from one place to another (equipment, stockers, under-track storage, etc.). For each of these activities, the factory’s MES is notified instantaneously.

GEM300 – SEMI E40, E87, E90, E94, E157

With the advent of 300mm manufacturing in the mid-to-late 90s, a global team of volunteer system engineers from the leading chip makers defined the GEM300 standards to support fully automated manufacturing operations. Starting at 5:00 o’clock on the infographic, the number of transactions per minute jumps almost 3 orders of magnitude, from the monitoring of 900 control jobs across 4000 process tools to the tracking of 360,000 individual recipe step change events. This level of event granularity is essential for the latest generation of FDC (Fault Detection and Classification) applications, because precise data framing is a key prerequisite for minimizing the false alarm rate while still preventing serious process excursions. In this context, more than 6000 recipe-, product- and chamber-specific fault models may be evaluated every minute.

Simultaneously, the applications that monitor instantaneous throughput to prevent “productivity excursions” and identify systemic “wait time waste” situations depend on detailed intra-tool wafer movement events. In a fab with hundreds of multi-chamber, single-wafer processes, 75,000 or more of these events occur every minute. gantt-chart-cycle-time

EDA (Equipment Data Acquisition) – SEMI E120, E125, E132, E134, E164, etc.

Rounding out the SEMI standards in our example gigafab is the suite of EDA standards which complement the command and control functions of GEM/GEM300 with flexible, high-performance, model-based data collection. The EDA standards enable the on-demand collection of the volume and variety of “big data” required from the equipment to support the advanced analysis, machine learning, and other AI (Artificial Intelligence) applications that are becoming increasingly prevalent in leading semiconductor manufacturers. As EUV (Extreme Ultraviolet) lithography moves from pilot production to high-volume manufacturing at the 7nm process node and beyond, the litho process area will become a major source of process data by itself, generating 10 GB of data every minute. This is in addition to the 100 GB of data collected from other process areas. graph-and-equipmentfolder

The End Result

The final wedge (12:00 o’clock) in our infographic highlights the real objective – which is producing the millions of integrated circuits that fuel our global economy and provide the technologies that are an integral part of our modern way of life. Assuming a nominal die size of 50 square mm (typical of an 8 GB DRAM), the 2.31 wafers we started at 1:00 o’clock result in almost 3200 individual chips. But none of this would be possible without the pervasive factory automation technology we now take for granted. So, as you finish reading this posting on whatever device you happen to be using, take a micro-moment to acknowledge and thank the hundreds of standards volunteers whose insights and efforts made this a reality!

Red_smart_factory-TWYou may not be responsible for running a gigafab anytime soon, but the SEMI standards used in this setting are no less applicable to any Smart Manufacturing environment. Give us a call if you’d like to know more about how these technologies can benefit your operations for many years to come. 

 

You can see this infographic and much more in the Cimetrix Resource center.

Resources

 *The Gigafab Minute was inspired by an analogous explication of the scope and impact of today’s Internet from Lori Lewis and Chadd Callahan of Cumulus Media, and published on the Visual Capitalist web site (http://www.visualcapitalist.com/internet-minute-2018/)

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

SECS/GEM series: Message Logging

Posted by Tim Hutchison: Senior Software Engineer on Sep 19, 2018 10:51:00 AM

In 1977, the classic movie "Close Encounters of the Third Kind" was released.  Towards the end of the movie, there is a dramatic "conversation" between the space aliens and the humans. One of the scientists makes the statement, "I hope someone is taking all this down."

What they really wanted was message logging!

Just like software logging is important for troubleshooting an application, logging the detailed message traffic between a factory host and the manufacturing equipment is just as important for troubleshooting.

For example, a host sends a command, and the equipment behaves based upon the message, but something does not work as expected.  It would be very helpful to see the message that was sent and the reply from the equipment, in conjunction with any other logs from the equipment to determine where the problem is located.

The format used to display/represent the logged messages is also very important. The latest industry standard for SECS message formatting is SEMI E173, the Specification for XML SECS-II Message Notation (SMN).

Here is an example:

<?xml version="1.0" encoding="utf-8"?>
<SECSMessageScenario xmlns="urn:semi-org:xsd.SMN">
                <Comment time="2018-02-05T18:19:20.365Z">State Change NotConnected</Comment>
                <Comment time="2018-02-05T18:19:20.400Z">State Change NotSelected</Comment>
                <HSMSMessage time="2018-02-05T18:19:20.394Z" sType="Select.req" direction="H to E" txid="1">
                                <Header>FFFF0000000100000001</Header>
                </HSMSMessage>
                <HSMSMessage time="2018-02-05T18:19:20.417Z" sType="Select.rsp" direction="E to H" txid="1">
                                <Header>FFFF0000000200000001</Header>
                                <Description>Communication Established</Description>
                </HSMSMessage>

Here is an S5,F5 example:

<SECSMessage s="5" f="5" direction="H to E" replyBit="true" txid="7" time="2018-02-05T18:19:20.507Z">
    <SECSData>
        <UI4 />
    </SECSData>
</SECSMessage>
<SECSMessage s="5" f="6" direction="E to H" replyBit="false" txid="7" time="2018-02-05T18:19:20.507Z">
    <SECSData>
        <LST>
            <LST>
                <BIN>0</BIN>
                <UI4>1</UI4>
                <ASC>Alarm 1 Text</ASC>
            </LST>
        </LST>
    </SECSData>
</SECSMessage> 

The SMN format is ideally suited for:

  • Capturing the HSMS header information in a clear way
  • Logging messages in an exact, binary format
  • Reading the logs using software
  • Creating a host or equipment emulator, since it is easy to read the logging from a software application and play it back.
  • Extracting data from the SMN logs

The logs can be captured by the Equipment, Host, or even a "network sniffer" like Cimetrix's CIMSniffer utility.

Cimetrix’s Logviewer utility supports SMN logs as well:

message logging blog image

With these standards and tools available, there's no reason to be like the scientist in Close Encounters, hoping that the messages were being logged.  Turn on logging!

Cimetrix's CIMConnect, HostConnect and SECSConnect all provide message logging in the SMN format.

Click here to read the other articles in our SECS/GEM Features and Benefits series. 

To download a white paper with an introduction to SECS/GEM, Click below:

SECS/GEM White Paper

Topics: SECS/GEM, Smart Manufacturing/Industry 4.0, SECS/GEM Features & Benefits Series