Finally, the quality of the Cat5 cable used can make a significant difference in performance.  The outer jacketing should be pliable.  Some of the cheaper brands have a very brittle outer jacketing that can break in tight bends and get damaged as it is pulled through conduit leading to damage of the underlying twisted pairs.  Another feature that I find important is bonded pairs.  This means that the two wires in each of the four pairs are physical bonded to one another.  The benefit of this is that the twist construction of the cable is maintained better as the cable is bent.  Cable that does not feature pair bonding can actually have the pairs separate in bends which reduces cross talk cancelation.

I recently attended a good presentation on EBR systems [ok full disclosure, it was a system that we installed and a fellow colleague was presenting].  Naturally, a Q&A session followed the presentation; during the Q&A somebody asked a question about the payback. 

The interesting thing about the question was the frame of reference of the asker; paraphrasing the exchange…

Asker:  “How much reduction in cycle time did the EBR system provide to the operators”? 

Presenter:  “None really… it was a wash.” 

Asker: “Then why do it?”

I believe that the asker was from a CPG background and thusly so, was of the mindset that EBR/Work ticket systems should let to a direct labor time savings.  Of course the EBR system will lead to time savings, but where is the question.  [As the presenters, did answer] Some of the savings is in OPERATOR direct labor (transcription time, manual logging time, etc.) however, it is in QA REVIEW time that is dramatically reduced.  Naturally there are some other reasons supporting a system like this:

• •Better Data
  • •Improved accuracy and consistency of the batch record
  • •Increased speed of product introductions and process changes
• •Production
  • •Reduced cost of compliance
  • •(Some) Increased productivity – i.e. verified by

The major point here is there are a wide variety of reasons that systems are put in place, MESA has defined these as Strategic Initiatives, some of which are Lean Manufacturing, Quality and Regulatory Compliance, Product Lifecycle Management, Real Time Enterprise, Asset Performance and etc.  When considering implementing those, make sure to look up and down stream to fully recognize impacts and capture all benefits.

Industrial Ethernet works on the same principles and protocols as any other Ethernet network.  In a nutshell, devices place units of data on the wire called packets.  Packets generally have a source and a destination.  When one device sends a packet directly to a second device, the process is called unicasting.  When a device sends a packet to all other devices on the network, the process is called broadcasting.  Finally, when a device sends a packet to specific group of other devices on the network, the process is called multicasting.

You might be asking yourself:  “where would multicasting be used?” One example that is often used in the IT world is a live camera feed.  If twenty people want to view a live camera feed, the camera shouldn’t have to manage twenty individual conversations, so instead, the twenty devices that will be showing the feed subscribe to a multicast group associated with the camera.  The camera sends packets to a multicast group destination address and the devices subscribed to that group receive and process those packets.

So, where does this apply in an industrial controls network? The first example that comes to mind is the use of producer and consumer tags on Rockwell Automation’s Controllogix platform.  One processor is a producer while one or more are consumers.  The consumers subscribe to a multicast group served by the producer.

The potential problem with all of this is that many switches handle multicasts as broadcasts which creates a large volume of traffic on the network and can cause performance problems due to the packets being forwarded to every port on the network.  The simplest solution to this is to implement IGMP (Internet Group Messaging Protocol) snooping.  This is a feature that is available on some managed industrial Ethernet switches and on many standard duty managed switches.  Once IGMP snooping is enabled, the switch will remember which ports have devices that are members of a particular multicast group and will forward multicast packets only to the devices that should be receiving them.  This will greatly reduce network traffic especially if you have a large number of devices utilizing multicasting on your network.

I recently generated the content for a mailing piece targeted at our Life Sciences Clients here at Avid addressing Paper-On-Glass… This is something that I feel strongly about, and decided to re-host here – so without further rambling…

For many, the concept of Paper-on-Glass (simply replacing the existing paper batch ticket/ink with a computer screen, i.e. glass) seems like the logical, low-risk evolution of automation systems.

Of course, we all know that implementing even this seemingly low-risk evolution will require a large team, representing every facet of the business (operations, quality assurance, IT, engineering and validation), due to the impact of the change. But a Paper-on-Glass system is worth it, because it can generate an EBR (electronic batch record), right?

The real question should be: While that team is together, can something better be done?

Paper-on-glass systems (like typical paper-based) require review after the fact and not in real-time (or by exception). The next step up, from Paper-on-Glass, focuses the exception handling during the EBR execution. Reviewing the process during the manufacturing process allows the operator on the shop floor to address exceptions as the manufacturing rules are enforced in real-time. This reduces wasted time, money and materials and decreases the review time.

Any change to the batch ticket will require cultural transition and careful change management.  Again, why limit your focus to simple remove the paper? Some additional areas to consider with the implementation of any EBR system should be:

• •  Total Quality Control – Tracking material lots and manufacturing within the process
• •  Scheduling – Queuing and optimizing production based on best-fit algorithms
• •  Recipe Management – more than weigh and dispense, formulation, set-up parameters, tolerances and labels, and prepositioning of set points
• •  Inventory Management – tracking “work-in-process” and state of assets, i.e. clean, used, in-process
• •  Maintenance – Monitoring equipment performance, tracking usage for preventive maintenance and downtime

 

Welcome to Level3…a manufacturing information space blog.  Here we will discuss a variety of topics related to the space that sits between the PLCs/DCSs controlling your manufacturing process and the Enterprise Resource Planning (ERP).  We will tend to focus on integrating from the ‘Shop-Floor’ up as opposed to ERP down or “Big Bang” MES packages.  Posts will be generated by several of us here at Avid, some leading experts outside of Avid, and hopefully comments by users too.

Some of the topics we have planned are:  Historians, Reporting, OEE, KPIs, Networking, Virtualization and so forth…