Digital TechnologyFieldbus allows more accurate transmission of the signal than the traditional 4-20mA setup, by virtue of being digital. Here we can see a comparison between the two systems. Both accept a digital signal,but the 4-20 has to convert the signal to analogue to transmit it, which causes a loss in accuracy because of the conversion algorithm from digital to analogue, and a further loss of accuracy upon conversion back to a digital signal at the other end..Fieldbus does not have to do this conversion, it just carries the digital signal right through without any need to convert it.In addition, the 4-20’s transmission can suffer from current leakage, further reducing the accuracy of the reading. Fieldbus does not have that problem, and in addition the Fieldbus system is self monitoring, performing checks on the signal when it is transmitted and received to verify there is no degradation during transmission.Utilising digital transfer means that the Fieldbus can deliver the signal with 100% accuracy.
Foundation FieldbusWe think that Foundation Fieldbus is the best solution for your requirements for five key reasons. First, it’s built on mature technology that is already proven in the marketplace, which means less risk. It’s also more efficient to set up, reducing your implementation costs and effort. Once it’s in place, its self-monitoring capabilities will save you a huge amount of time and effort that you’d normally spend on routine maintenance tasks, and we can also show you how it compares in terms of performance with the traditional setup, giving you much greater confidence in the quality of the readings. Finally, Fieldbus is a much more reliable solution than the traditional system, so there’s less risk of plant downtime which can be extremely costly.First let’s look at how the technology is already working in various types of applications all over the world
Foundation FieldbusWe think that Foundation Fieldbus is the best solution for your requirements for five key reasons. First, it’s built on mature technology that is already proven in the marketplace, which means less risk. It’s also more efficient to set up, reducing your implementation costs and effort. Once it’s in place, its self-monitoring capabilities will save you a huge amount of time and effort that you’d normally spend on routine maintenance tasks, and we can also show you how it compares in terms of performance with the traditional setup, giving you much greater confidence in the quality of the readings. Finally, Fieldbus is a much more reliable solution than the traditional system, so there’s less risk of plant downtime which can be extremely costly.First let’s look at how the technology is already working in various types of applications all over the world
Registered DevicesI’m now going to show you how the 600 plus devices came to be registered over time – as you can see the uptake of new registrations has been steadily climbing year on year, and the number of renewed registrations is also trending sharply upwards, indicating that interest and demand for the system is growing consistently.
Registered DevicesOne factor contributing to this growth is the breadth of applications fieldbus supports – 600 devices spread across measurement, control, host and network – whatever you need from your system, fieldbus will be able to support the devices that you need to deploy.
Market MomentumBecause of this, Fieldbus is quickly gaining momentum in the marketplace. Over 1 million devices are in service worldwide with significant presence in all regions, and 68% of all new projects globally are choosing Foundation technology.
Reduced Wiring and InstallationSo Fieldbus technology has already attracted a huge following due to the breadth of its application. But when considering any new installation, you have to think about the time and resources involved in the setup.
Reduced Wiring and InstallationLet’s compare the setup between Fieldbus and the traditional analogue approach. In the 4-20 system, each device has an intrinsic safety barrier, additional wiring; additional control room space, and a ton of documentation, adding up to a complex and time-consuming commissioning process With the digital Fieldbus system, there is a single IS barrier, which means reduced wiring, less control room space, and simpler configuration, making it quicker to commission. Because it’s easy to setup, you incur less costs at the commissioning phase and get to full operation more quickly.
Proactive MaintenanceOnce any system is up and running, you have to consider the impact of maintaining it.
AnalogueA traditional analogue control system consists of hundreds of wires, each pair carrying data from single devices back to plant level controllers, and then on to the control room. The controller gets information on traditional process variables – for example temperatures and levels.
AnalogueA traditional analogue control system consists of hundreds of wires, each pair carrying data from single devices back to plant level controllers, and then on to the control room. The controller gets information on traditional process variables – for example temperatures and levels.
Foundation FieldbusFoundation Fieldbus requires much simpler wiring architecture and delivers a tremendous amount of additional information to the controller. Fieldbus’ 'predictive intelligence' provides information on, for example, wear and tear, installation issues, process variations, premature wearing, and so on, giving the controller a much more comprehensive view of plant performance.
MaintenanceThis is important because it helps you streamline your maintenance operations. 86% of maintenance is either reactive (it happens too late because something’s already failed) or preventive ( which may be unnecessary if everything is working correctly).Imagine this being the case with an airline – preventative maintenance could eat up a massive amount of time and resources checking every single component on every aircraft, but reactive maintenance would mean a disaster has occurred. What you need is a system that could just alert you whenever something needed to be seen to - early enough to catch the problem before it happens - and didn’t require regular checking when everything is running well.
Predictive IntelligenceThis is where the ‘predictive intelligence’ of Foundation Fieldbus comes into its own. Where classical automation equipment just carries information on process variables, Foundation fieldbus supplies data on wear, installation issues, process variations, machinery health, and asset optimisation.With classical automation, your equipment might have problems, but you wouldn't know until it’s picked up by a routine inspection or it fails in the field, and you’re probably spending a lot of time and resources doing routine checks in the meantime.
Proactive MaintenanceHere’s an example of how one company measured significant improvements to their maintenance workflows. This shows how their man hours were spent on maintenance tasks. The majority of time was spent on routine checks, or on checking components that were working with no problem. After switching to Foundation Fieldbus, they were able to eliminate over 60% of those unnecessary tasks due to Fieldbus’ predictive intelligence capability. Imagine what you could do if you could redeploy 60% of your man hours into other activities.
Tighter ControlSo we’ve seen how Foundation Fieldbus can save you a great deal of unnecessary maintenance time, let’s now turn to performance and see how it measures up against the traditional asynchronous systems.
Control in the Field StudyI’m going to show you a study that was commissioned by Foundation Fieldbus EMEA in cooperation with industrial systems and control and the university of Strathclyde. The study tested Foundation Fieldbus against traditional DCS asynchronous systems
Control in the FieldWe’ll see that Fieldbus’ ‘Control in Field’ capability has a big impact on the results. In the diagram, we can see two measurement devices and a valve connected to the DCS via the H1 card. In the traditional setup, a measurement device that needs to communicate with a control device sends its signal to the H1 card. The signal is then transferred to the DCS where it is processed, and then sent across to the control device. With Control in Field enabled, the devices can communicate independently of the H1 card – the signal goes directly from the measurement device to the valve.
Control in the FieldWe’ll see that Fieldbus’ ‘Control in Field’ capability has a big impact on the results. In the diagram, we can see two measurement devices and a valve connected to the DCS via the H1 card. In the traditional setup, a measurement device that needs to communicate with a control device sends its signal to the H1 card. The signal is then transferred to the DCS where it is processed, and then sent across to the control device. With Control in Field enabled, the devices can communicate independently of the H1 card – the signal goes directly from the measurement device to the valve.
ComparisonLet’s look at the processing speed for the CIF-enabled system and how this breaks down. First there’s a 20 ms time to execute the instruction in the flowmeter. Then 30 ms for the data to transfer to the control device, 30ms for the PID execution in the device, and 25 ms to execute the instruction, giving a total latency of 105ms.Now, with the same setup but having a Control in Process system in place instead of Control in Field, there’s the same 20ms for the AI execution in the meter, then a 30ms transfer time to the PID. The data then has to transfer to the PCS, and then 20ms for the PID execution in PCS. Then the data gets transferred from the PCS to the valve device, which takes 30 ms, and the instruction is executed in the device – 20ms. This gives a total latency of 125ms, which doesn’t look much more than the Control in Field setup, until you consider the asynchronous processing rate between the card and the PCS. Because of the sheer number of processes happening at any one time, the PCS has to run more slowly, which introduces an additional 500ms of ‘jitter’ and bumps up the total latency to at least 625ms - significantly slower than the Control in Field system.
ComparisonLet’s look at the processing speed for the CIF-enabled system and how this breaks down. First there’s a 20 ms time to execute the instruction in the flowmeter. Then 30 ms for the data to transfer to the control device, 30ms for the PID execution in the device, and 25 ms to execute the instruction, giving a total latency of 105ms.Now, with the same setup but having a Control in Process system in place instead of Control in Field, there’s the same 20ms for the AI execution in the meter, then a 30ms transfer time to the PID. The data then has to transfer to the PCS, and then 20ms for the PID execution in PCS. Then the data gets transferred from the PCS to the valve device, which takes 30 ms, and the instruction is executed in the device – 20ms. This gives a total latency of 125ms, which doesn’t look much more than the Control in Field setup, until you consider the asynchronous processing rate between the card and the PCS. Because of the sheer number of processes happening at any one time, the PCS has to run more slowly, which introduces an additional 500ms of ‘jitter’ and bumps up the total latency to at least 625ms - significantly slower than the Control in Field system.
Settling Times: Fastest ProcessLet’s look at settling times for the Control in Field system versus the Control in DCS. This shows the fastest process, where our system is 60% faster to settle than the other.For ‘fast’ process speeds, CIF settles 55% quickerFor fast speed processes, CIF settles 66% quickerAnd for medium-speed processes, CIF settles 39% faster.
Settling Times: Fastest ProcessLet’s look at settling times for the Control in Field system versus the Control in DCS. This shows the fastest process, where our system is 60% faster to settle than the other.For ‘fast’ process speeds, CIF settles 55% quickerFor fast speed processes, CIF settles 66% quickerAnd for medium-speed processes, CIF settles 39% faster.
Settling Times: Fastest ProcessLet’s look at settling times for the Control in Field system versus the Control in DCS. This shows the fastest process, where our system is 60% faster to settle than the other.For ‘fast’ process speeds, CIF settles 55% quickerFor fast speed processes, CIF settles 66% quickerAnd for medium-speed processes, CIF settles 39% faster.
Settling Times: Fastest ProcessLet’s look at settling times for the Control in Field system versus the Control in DCS. This shows the fastest process, where our system is 60% faster to settle than the other.For ‘fast’ process speeds, CIF settles 55% quickerFor fast speed processes, CIF settles 66% quickerAnd for medium-speed processes, CIF settles 39% faster.
Presence of Disturbance: Fastest ProcessTurning to the Presence of Disturbance test, which measures the variation of the signal when exposed to an outside disturbance. We can clearly see that the Control In Field system generates significantly less variation and ends up closer to the set point than the Control in DCS system.
Presence of Disturbance: Different ProcessesWhen we look at this in terms of deviation from the setpoint at different process speeds, we can see a significant improvement at the fastest speeds, 50% improvement at Very Fast, 55% better at Fast, and 35% improvement at medium speed. So the control in field system provides 35-65% better rejection of disturbances than the asynchronous control in DCS.
Impact of Tighter Control LoopIf The control is not tight, you’d need to leave large margin for error in case any disturbances pushed values beyond the control limit. Manual control would leave a large margin of error, pneumatic control considerably less, analogue control systems even better, but digital systems leave the least room for error.Because Control in Field is a digital system, it's possible to set the setpoint much nearer to the control limit,which allows more efficient use of energy, more accurate readings and better raw material utilisation.
Recommended for Fast Loop ResponseA spokesperson from Shell Global Solutions International had this to say – recommending our technology and pointing out some of the major benefits that they found the system delivered.
Greater ReliabilitySo, we’ve seen how Foundation Fieldbus performs at the sharp end, but what about long term performance and reliability?
The Need for ReliabilityHere’s a terrifying statistic from ARC insight last year. 20 billion dollars lost due to device failure. And even worse…. It could be prevented.
ReliabilityFoundation Fieldbus commissioned a study by Edward Marszal, a safety consultant who works with data supplied by EXIDA on instrument reliability. Essentially, Marszal took well-defined safety system methodology and used it to test reliability. The first thing to note about the Control in Field system versus the asynchronous system is that it uses less parts, which means less to go wrong, but also remember the additional diagnostic coverage we mentioned earlier. Predicative intelligence in the devices makes them much less likely to fail because you’d be alerted that something needed attention.
ReliabilityFrom analysis of the components used in each system, the study generated ‘fault trees’ showing all of the possible issues arising with both systems – as you can see, there is far more scope for failure in the analogue system, which also accounts for the huge difference in mean time to failure statistics: just under 16 years for the analogue system, versus, 48.2 years for the Foundation Fieldbus with Control in Field. All of which demonstrates that Foundation Fieldbus with Control in Field is a much more reliable solution that can help reduce costly downtime.
Customer ExperienceHere’s an example of how Control In Field helped the Shin-Etsu plant in the Ntherlands. In this plant, the card in the DCS failed, which meant communication between the devices was no longer happening. But instead of shutting down the plant, operators were able to use Control in the Field for direct communication between measurement devices and valves. This meant they could continue operating while the DCS issue was being resolved, with no need for a costly shutdown of the plant.
Customer ExperienceA spokesperson for ShinEtsu had this to say… this inherent backup capability of Control in Field saved them from not one but two plent shutdowns and meant they could continue operating normally.
Foundation FieldbusIn summary, Foundation Fieldbus is built on technology that’s already proved its worth in the industry hundreds of times over, making it a low-risk choice. Because of the lower effort and space required to install it, you can commission it faster. The predictive intelligence it delivers can help you reduce your maintenance overheads, and its performance gives you better control over the signal than asynchronous systems. You’re also getting a much more reliable system, and one with built in backup capability to minimise costly downtime issues. So, can we have your business?