Emerson Process Experts

If your current work processes are causing delays in getting your manufactured products released for sale, you may want to catch Christie Deitz', Electronic Workflow for a Bioreactor presentation. She'll be co-presenting with an automation engineer from a leading pharmaceutical manufacturer at the 2010 World Batch Forum North American Conference, which will be held May 24-26 in Austin, Texas. You may recall Christie from earlier Life Sciences-related posts.

The presentation describes a large, complex project with a complete paperless manufacturing goal that supports release by exception. For those not familiar with regulated industries, regulatory bodies like the U.S. Food and Drug Administration (FDA) require that all exceptions in the manufacturing process be investigated and signed off before product can be released for sale.

Release-by-exception implies that the exceptions can be reviewed and addressed in real-time, not after the fact, which is typical for paper-based workflows. By moving to a paperless workflow, the number of exceptions can be reduced as the manufacturing rules are enforced in real-time. The business benefit is to reduce the time finished products are warehoused waiting for the exceptions to be addressed. From a financial perspective, this reduces inventory costs and increases inventory turnover.

The project included a DeltaV automation system, Syncade manufacturing execution system, SAP enterprise resource planning system, SmartLab laboratory information management system, and Maximo instrument asset management system. All were connected with the Syncade software to drive an electronic workflow process and final electronic batch record.

Christie and her co-presenter offer examples of manufacturing steps, role of electronic workflow, and how it ensures quality and/or expedites the review and release process. An example is the quality assurance (QA) review process. The electronic workflow enables presentation of the electronic batch record (EBR) in a checklist form for QA review. It ensures quality and/or expedites the review process by launching the notification for QA review in real time and providing a view that displays the relevant information in the familiar QA checklist format.

The presentation also shares the S88 (ISA-88) approach taken, specifically the bioreactor process control at the control system level and workflow connections at the MES (manufacturing execution system) level between the software applications mentioned above.

I won't steal the thunder from the best part, lessons learned, other than to share one example of the importance of finalizing the vision and requirements early and documenting them. It's critical for the success of large, complex projects to establish and connect this common vision with the project team and workflow stakeholders to move the project along and minimize rework.

If you're looking for ways to optimize your process manufacturing workflows, you'll want to attend this session on May 26 at 2:15pm.

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Bioprocess International magazine recently published an interesting article, The Time Has Come for Automation in Bioprocessing. Bioprocessing has moved down the spectrum from art to science where automation can efficiently and reliably handle routine tasks.

The authors described the advancement of automation:

Major companies have introduced automation in the form of communication between traditionally standalone devices such as blood gas analyzers and nutrient monitors. These are tied into automated sampling solutions, allowing such devices to run all day, every day without significant human intervention. The next step is tying that into bioreactors and chromatography skids to create an automated loop whereby a process is monitored continuously by a controller, which communicates its findings to technicians who can then make decisions and act upon them.

One of the experts cited in the article was industry consultant, Larry West of Aspen Brook Consulting. He has prior experience with the DeltaV system and its application in the Broadley-James Bionet bioreactor control system and the Finesse TruLogic solution.

In the article, Larry describes a biotech facility where they used a classic automation solution (the DeltaV system in this case) and apply it to biotherapeutics and running the fill-finish operations on the DeltaV system. He noted how GE Healthcare and the DeltaV team worked together:

...to create a chromatography skid that allows discrete (on/off) functions to be handled by the GE Unicorn platform while analog functionality is managed by Emerson's DeltaV system.

He went on to note other automation advancements:

...we saw a SciLog TFF skid controlled by the Emerson DeltaV platform, which manages associated discrete I/O. Such application progressions ensure the continued evolution of automation throughout a product's life-cycle, beginning in research and ending in fill-finish.

The article sums up Larry's thoughts on bioprocessing automation:

...automation is a valuable tool that "can be used to benefit all of us as an industry. It doesn't have to be perceived as a weapon with which to reduce headcount or eliminate people's roles. It really is a tool. And as long as we keep that in perspective and wield it accordingly, this industry will make some serious advances."

I highlighted some of the Emerson-specific solutions mentioned, but you can give the article a read to see other suppliers' solution and consultants' thoughts about automation advancements in this important industry.

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ModelingAndControl.com's Greg McMillan was giving his pH Control Solutions webcast a dry run yesterday and it was an opportunity I didn't want miss. I always learn something when I'm around Greg. Greg will be conducting this live ISA web seminar on pH Control tomorrow, March 10, 2010 at 2-3:30pm U.S. Eastern (GMT -5) time. It's not free, so visit the ISA webinar registration page to sign up.

It's a chance to listen to Greg and ask questions about challenges and solutions to your toughest pH Measurement and Control solutions. He derived some of his thoughts from his book Advanced pH Measurement and Control, 3rd Edition.

Those that know Greg know he loves his Top Ten, David Letterman-style lists. In this presentation, he'll share his top ten signs of a rough pH startup. I'll share one of them. You know you've got a rough pH startup when the plant manager leaves the country.

pH poses measurement challenges in sensitivity and rangeability like no other. Normally, an instrument engineer considers a turndown ratio or rangeability of 100 to 1 as quite large. Try 100,000,000,000,000 to 1 for a pH sensor measuring a pH 0 (1.0 hydrogen ion/0.00000000000001 Hydroxyl ion concentration) to pH 14 (0.00000000000001 hydrogen ion/1.0 Hydroxyl ion concentration). It was enough zeros that I was losing count, so I cut and pasted from Greg's presentation!

Another big challenge is the non-linear, s-shaped titration curves (pH versus reagent/influent ratio). If you follow the link for titration curves to the Wikipedia link, you'll see a picture of this non-linear curve. Greg noted that the steep vertical part is deceiving. As you zoom in it's actually another titration curve. As such, it's critical to get numerical values and a sufficient number of data points around the setpoint. Greg describes various titration curve scenarios including weak acid/strong base, weak acid/weak base, multiple weak acids/weak bases, and strong acids/weak bases.

Greg describes how large savings in reagent is possible for the flat parts of the titration curves. pH sensor drift can have a large impact on the reagent calculations and Greg discusses the advantages of doing Feedforward flow control on the ratio of reagent to influent flow. The Feedforward control requires pH feedback correction unless the setpoint is in the flat part of the titration curve. He recommends using Coriolis mass flow meters and having constant influent and reagent concentrations.

He covers much more from the construction and operation of double-junction combination pH electrodes to the need for three pH probes and a mid-select algorithm to handle the natural drift in pH measurements. He offers many pH control strategy examples such as cascade, full throttle batch, linear reagent demand batch to name a few.

If you are fighting pH measurement and control issues at your plant, it may be worth the fee and time to hear Greg and have the opportunity to ask your questions of him directly.

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John Rezabek closes his ControlGlobal.com Surprise! Field-Based Control Beats DCS article with the thought:

The SP50 committee set out years ago to define and specify a robust, vendor-independent controls suite exploiting the intelligence of microprocessor-based field devices that would equal or exceed the "bulletproof" DCSs of the 90s. They succeeded.

The source of this conclusion is two recent studies, one conducted by Emerson fieldbus consultants Dan Daugherty, Mark Coughran, and Ferrill Ford. The other is by Kenexis Consulting's Ed Marszal, who applied a similar reliability model used with safety instrumented functions to Foundation fieldbus (FF) control loops running PID in the FF device. The common vernacular for this type of control is control-in-the-field (CIF). I described and embedded Dan, Mark, and Ferrill's Emerson Exchange presentation in a post, Dispelling a Rules of Thumb in Foundation Fieldbus Segment Sampling Rate. In John's article, he summarizes this study:

One of the things revealed was that control in DCS did not benefit substantially from over-sampling, which involves running the macrocycle two or more times faster than the DCS PID block. The other notable result was that control-in-DCS could not approach CIF in performance, especially when macrocycles (the deterministic cycle time of all the function blocks on a fieldbus segment) were cranked down to as little as 150 milliseconds. CIF was distinctly better and had no problem matching the performance of fast, pure analog (4-20 mA) control.

Control in the field has the advantage of single loop integrity, diagnostics, and signal status across the fieldbus segment. For the reliability study comparing control in a DCS controller versus CIF for a simple PID loop, John quotes Ed's findings:

Fieldbus is significantly better--mean time to fail (MTTF) of 48.2 [years] versus MTTF of 15.9 [years].

The numbers were rerun using field devices with the same reliability numbers and the CIF case again had greater MTTF. I sent Dan a link to the article and asked what thoughts he might have to share. He wrote:

It is good to see confirmation of our conclusions from independent researchers using different methods of analysis. In the tests ran in the Marshalltown flow lab, Mark Coughran, Ferrill Ford and I not only demonstrated the superior performance of FOUNDATION fieldbus deployed as Control-in-Field (CIF), but were able to show the relative contributions of the control algorithm update rate and the I/O sampling rate of the macrocycle. This is useful information for economical control system design to the necessary performance requirements. We were able to dispel the myths that inhibited the choice of FOUNDATION fieldbus due to unnecessary overdesign, which in turn leads to low density and higher cost segment design.

I fully concur with the conclusions that use of FOUNDATION fieldbus can lead to higher availability than one can get with point-to-point I/O. Without going into all the complicated algebra, the common sense view is that one H1 card for 16 loops (8 loops per segment x 2 segments per card) will have a lower failure rate than 4 I/O cards for the same number of loops. Then once one chooses to use redundant H1 cards and fieldbus power supplies, the availability is much, much higher. Clearly, FOUNDATION fieldbus is by far the most reliable way to deploy control. (I assume that by now, everyone understands individual devices and short circuits are isolated from the segment through the field connection hardware.)

Given these performance and reliability results, the case favoring this highly distributed control-in-the-field approach continues to build.

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