The first areas that spring to mind when a process professional is challenged to reduce process control costs are usually purchase cost and installation. They are the obvious ones and they are the easiest to define and list, when viewed as part of a system however, purchase cost plays only a small part; managing the multiple signals from sensors and transducers differently can radically affect the total cost of ownership for that process system…
Careful analysis conducted by Volker Erbe, Sensors Product Manager at process control specialist Bürkert Fluid Control Systems investigating the whole life costs associated with field devices and the control platform they are connected to, has revealed there could be far larger savings to be had from making changes to product selection at the initial stage of a project.
Volker carried out the research to help define costs more accurately for Bürkert process field devices; he then identified where costs lie within a whole life process application and quantified the results of making better decisions early on in a project. (see Picture 2 )
Initial costs
Planning is a cost which almost always justifies the investment. Purchasing has an administrative cost associated with it and we found that the equipment itself only accounted for around 17% of the initial cost.
Other items we took into consideration included support from both internal and external sources, installation, plus commissioning and start-up costs.
Analysis of initial costs
It is not until you reach this level of analysis that you start to see a pattern forming in the peripheral activities, and then start to appreciate the hidden costs. Only then do you begin looking to specify a solution that reduces indirect costs, knowing that the saving can be significant when compared to the initial purchase cost of the devices themselves. (see Picture 3 )
Operational Costs
We defined operational costs as recurring activities, including on-going hardware and software management, production monitoring and control, maintenance, service and repair, any enhancement carried out during the life of the product, additional documentation and then finally decommissioning including recycling costs.
Analysis of operational costs
To be totally accurate you have to analyse your own plant to have a base line which gives you information about the share of operating costs using your plant figures, identifying which area is of interest for achieving the best results in cost reductions. You can however use our broad analysis to draw some obvious conclusions. (see Picture 4 )
Each product should ideally have a wide range of usage, this leads to device consolidation and a reduced number of different products in use, this can then generate a virtuous circle which requires reduced training effort, allows more flexible staffing and reduced effort in all production.
The handling of a product must be easy and repeatable, this means no specialist tools required, hence no hidden costs and no need to carry large amounts of kit in order to have a wide range of tools to hand.
Data management should be easy, we realised that simple things such as the upload and download of settings, cross referenced with data storage capacity and easy configurability of multiple items made a huge difference to the end user. A more intelligent field device needn’t mean a more complex one to handle, because that would likely negate any cost saving in process.
All this research was taken into account in the design of our multiCELL 8619 compact field based process controller; this meant investing in multiple interchangeable control boards, plenty of on-board intelligence, plus set programs for controlling a variety of analogue and digital process signals via a simple menu structure that could be easily interacted with in a process environment.
The result of all this application knowledge in one product means it is hugely less expensive than a system including a separate controller, separate I/O, comms gateways and an HMI.
Maintenance, monitoring interrogation and data upload and download are all possible via one operator interface. It also means that selective access via password can provide data security and minimize handling errors by selective allocation of activities to different user responsibilities. On-screen instructions also mean quick learning and no need for a bulky manual or laptop to be at hand.
Integrated menus also support calibration routines for sensor, analogue inputs and outputs, allowing configuration without having to use separate tools and wiring. The device also has a signal simulation function for sensors, input and output signals and so supports easy start-up procedures.
Not only is the device easy to use, but standardisation is easy and the cost of on-going support and maintenance is minimised.
The device will tell you what version of its software or firmware it is running and allow easy updates and upgrades without losing custom parameter sets. If a device ever needs to be exchanged it can simply be replaced and the SD card used to transfer the operating parameters, providing a totally plug-and-play replacement for a very advanced process control function.
So where do you apply a product like this?
A typical customer for this type of new field multi-transmitter/controller has a process application with multiple sensor types and arrangements in use, plus actuators and valves for performing functions in recurring applications; all providing a variety of different signals at different rates and in different formats requiring a lot of different knowhow just for daily operation.
The solution would be to use a multiCELL multi-channel / function / transmitter / controller as a central device, connect all the different sensors, perform all the necessary functional configuration in only one device, and for each application store the configuration on an SD card for reuse.
Conclusion
Bürkert believes that there are substantial process control cost savings to be made from the complete lifecycle of a process multi-transmitter/controller, that cost reduction starts with device selection and savings are made both directly and indirectly. Each individual plant needs to carry out some analysis based on its own individual instrument usage, the kind of processes taking place and the individual operating conditions.
Thinking about usability throughout the product life cycle and the real TCO has led Bürkert to create a very different type of product and one that the company believes indicates the future for intelligent process field devices.
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