Together with the pH value, the redox voltage is one of the most frequent process variables in industrial and municipal effluent plants, as well as in installations for monitoring drinking water and bathing (swimming pool) water.
Matthias Kremer, Ulrich Braun, Dr. Jürgen Schleicher, JUMO
The methods of determination of hydrogen peroxide and PAA are not continuous measurements methods, but methods whereby the concentration is measured for samples taken at certain times.
These analytical methods are laboratory procedures requiring a considerable outlay in personnel and time.
In order to regulate the concentration of a disinfectant, it is advantageous if a electrical signal is available that is continuous and proportional to the concentration of disinfectant. This signal can then be used as the input signal for controlling a disinfectant metering system, i.e. the concentration can be completely automatically regulated.
A membrane-covered amperometric measuring cell can be used for monitoring the peracetic acid concentration and the concentration of hydrogen peroxide.
Measurement of the concentration of ammonia in aqueous solutions is a requirement in many application areas, such as for coolant monitoring and laboratory measurement. A fast and simple way of measuring ammonia can be achieved by using a membranecovered, gas-sensitive sensor that operates on a potentiometric principle.
But for successful measurement, several factors must be observed when handling and using of ammonia sensors. This brochure is intended to provide practical help for the users in these matters. A special emphasis is placed on the two application situations mentioned above.
Furthermore, the construction and mode of operation of the sensor is also briefly described.
"It's about time." Those are the words of the production manager for a Texas power generation facility when asked for his thoughts on wireless applications moving into the production side of the plant. He certainly is not alone, judging by the amount of wireless activity going on in those process manufacturing facilities today.
Does your plant suffer from high software maintenance costs, inflexible batch production, safety and environmental regulatory pressures?
The Ineos Acrylics Plant at Darwen in the UK was experiencing these problems which are experienced with many legacy batch control systems in the modern chemicals market. The problems can be overcome with an S88 compliant system and approach but the right structure is essential.
Reviewing the problems and plans to replace the system it was clear that a simple migration of the existing system would achieve little and that a complete re-structuring based on S88 was required. It was anticipated that this would give economic benefits of reduced software maintenance costs, increased production flexibility, reduced environmental/safety risks, all of which were achieved and more besides.
This paper describes the process, problems and achievements of the project.
Chris Morse, Engineering Group Leader, Honeywell IASD
The modelling of a Batch Process and breaking down into S88 modular components is key to an easy and cost effective control software solution.
This paper looks at the issues involved with engineering a batch control system, in relation to modelling, unit acquisition and transfers of material, including the use of generic coding techniques and multiplexing or unit relative design.
There are many ways to engineer a batch application even using S88 concepts. Real case studies will be used, where two batch applications have been engineered on the same site over the last 5 years. The first placed a high emphasis on control station coding and complexity within the phase and sequences. The later case was designed to fully use the capability of the Batch Supervisor to optimise engineering and maintenance and provide the functionality required.
A comparison of these two methodologies provides a good insight into the benefits and disadvantages of each, in relation to engineering, testing and on-going maintenance.
Paul Wilson, Batch Consultant, Invensys Software Systems (Foxboro)
The successful application of general recipes requires a significant break from the equipment centric S88 model of Master Recipes. The proven Modular Batch Automation concept, centered on the unit and equipment model, does not apply when equipment independent general recipes are developed. Even though a general recipe may define equipment constraints, it is not equipment centric, but instead uses materials as the primary organizational element. A general recipe defines the materials to be used, their order of addition or extraction, and the actions to be taken on the materials. This leads to a different set of rules to organize the general recipe procedural model. This paper defines the rules we have found useful for determining process stage and process operation boundaries. These rules include material and equipment constraints, but also include business level constraints associated with the identification and tracking of intermediate materials. These rules result in general recipes that can be readily transformed into process cell-specific equipment recipes for a variety of equipment layouts.
Dennis Brandl, Senior Director- Strategic Initiatives, Sequencia Corporation
21CFR11 took effect in August 1997 with little observed regulatory activity. However, that has changed and increasing numbers of FDA warning letters are being generated for software used for GMP, GCP, or GLP (GxP) purposes. This presentation addresses the impact of 21CFR11 on automated manufacturing systems and processes. Included is an overview of 21CFR11, a discussion of the processes needed to reach compliance including 21CFR11 interpretation, assessment and remediation activities, and some issues for legacy automated manufacturing systems. It will speak to the compliance issues for hybrid systems where there is a multiplicity of options between totally paper based and totally electronic systems.
Kathleen Waters, Manager - Automation IT, Genentech Inc.
Real-time thermal imaging provides rapid, intuitive understanding of dynamic thermal conditions and clues to their underlying causes. This paper discusses the latest infrared linescanner technological advancements and the newest developments simplifying implementation of these systems, while providing a higher level of performance in harsh industrial processing environments.
Voltage, current, temperature, pressure, strain and flow measurements are an integral part of industrial and process control applications. Often these applications involve environments with hazardous voltages, transient signals, common-mode voltages and fluctuating ground potentials capable of damaging measurement systems and ruining measurement accuracy. To overcome these challenges, measurement systems designed for industrial applications make use of electrical isolation. This white paper focuses on isolation for analog measurements, provides answers to common isolation questions and includes information on different isolation implementation technologies.
There are many issues to consider when measuring high-voltage. When specifying a data acquisition system, the first question you should ask is whether or not the system will be safe. Making high-voltage measurements can be hazardous to the equipment, to the unit under test, and to you and your colleagues. To ensure that the system is safe, you should provide an insulation barrier, using isolated measurement devices, between the user and hazardous voltages. Download this white paper to learn more about high-voltage measurements and isolation.
The COTS (commercial, off the shelf) revolution has changed commercial computing, created personal computing, impacted telecommunications, and made huge changes in the industrial environment. Most of these changes have been incredibly beneficial, while some have been problematic and some have caused FUD (Fear, Uncertainty and Doubt). This white paper discusses the COTS revolution and all the FUD that can come with it.
This application note discusses considerations when selecting lighting equipment and demonstrates how to utilize the Direct Drive lighting controller feature on the NI 17xx Smart Camera with LabVIEW or Vision Builder for Automated Inspection.
This paper presents the results of tests conducted on ways of reducing the four types of noise encountered in electronic instrument circuits.
The use of computers and other sensitive electronic equipment in process instrumentation systems has demanded that more attention be give to electrical noise pickup in instrument circuits.
The superior performance of aluminum-Mylar tape shields in comparison with copper braid and copper served wire shields for static noise rejection is described.
The effect of twisting wires to cancel magnetic noise is compared to various shielding materials. Twisting the wires is shown to be the most effective practical way of reducing magnetic noise.
The control of common mode noise by the proper grounding of shields in thermocouple circuits is shown. The use of single grounding points in shield circuits grounded at the couple is recommended. Multipair cables with individual isolated pair shields are recommended.
Comparative results on cross talk elimination in multipair cables are presented. Individually shielded pairs are recommended as the most practical means of cross talk rejection in instrument circuits.
Dekoron Division, Samuel Moore & Company. Bruce E. Klipec