The problem of monitoring today is not to get data, but to quickly evaluate it and take appropriate action in technology. Where is the interface between what is better left to the system and what the operator should do?
Control system levels
Control system with superstructures can be divided into several levels:
FIG. Four levels of control system
Normal system operation occurs at the three highest levels. At the PLC level (automation stations and peripherals), basic operations are performed using local control via the display, touch screen or panel on the control cabinet. It is an acknowledgment of alarms, because it is good to see the technology and control it also physically, as well as emergency or service manual interventions, etc. The operator responds to immediate operating states.
Visualization (SCADA) already provides a more comprehensive view, especially important are historical values over time, system event logs, and alarm history. This is data that is either not available at all in the automation stations or is inconvenient to work with. In historical data, for example, a technician can detect the oscillating control loop, trace the causes of technology failures, or find the potential to change control parameters and thereby save energy. However, the SCADA system still serves primarily for the operation – keeping the technology in operation.
Above visualization is a system for energy management. It no longer primarily works with current data. It is used for long-term evaluation, comparison of buildings among themselves and possibly for other tasks, for example, it can contain service modules including a ticketing system or be connected to other business management systems. It is usually used by the power engineer, a worker who is not in charge of the operation (normal operation), but the long-term concept of operation, purchase of energy and their economical use.
Let’s look at a few examples to show how some typical customers have coped with these three levels of service.
Large data center, Prague
Data center that manages hundreds of servers, provides their power, air conditioning and security. The entire control system was created gradually, initially only communicative meters and input cards were installed to monitor the presence of voltage on the supply circuits. The operator had a web interface with current values, which was sufficient for operational supervision. With the climate control system, the need for visualization with historical values has become increasingly a task typical for the SCADA system. However, the customer requested web access directly to the process stations. In parallel, an energy management system connected with customer management (CRM) was created. It has several basic functions:
- it provides a list of customers that could be affected by a breakdown or planned shutdown of one of the equipment or power circuits
- it gathers historical data for energy cost allocation
- this allows manual or automatic creation of alarm tickets, forwarding to service organizations (subcontractors) and checking their status
- automatically generated tickets are also used for planning revisions and regular inspections.
The system also provides helpdesk data so that technicians in the service can see the current technology situation and status at any time. However, this would be a task for visualization (SCADA); but the actual values were brought to the system as embedded web pages from web servers in individual PLCs. The transition to a full-featured web-based SCADA system was not realized until several years later.
The customer initially insisted on the fact he does not need the SCADA system: for the actual values (fault monitoring) he only needs web interfaces and the CRM system has little to do with it. This approach had its logic: management had experience from previous periods, when the assignment for the complete system had been filed until the implementation had dropped. The client therefore wanted immediate functionality in order to operate the data center. Thanks to the modularity of the control system, the visualization could have been added later without much of the work from the previous stages being wasted. Data from CRM are also used for long-term evaluation of energy parameters, the EMS system itself is not installed.
Large data center, Moravia
Programmable process stations collect data from electricity meters, sensors, auxiliary contacts of circuit breakers and other peripherals. At the moment, the values are only available for the operator from the PLC web pages, the SCADA system installation was offered. The customer is considering implementing his own system into which he integrated online data from monitoring stations. The CRM system itself would also deal with storing history and other SCADA functions and probably EMS (Energy Management System).
This solution would mean that the system can be maximally customized: the customer develops it himself. He can set development priorities, expand the system only if he has free development capacity, decides on implemented functions. On the other hand, if a professional solution is to be developed, it has to deal with the source code, versioning, backup, documentation, etc. It is always necessary to consider whether the development of his own system pays off and whether it is not better to stick to his core business. The actual development is certainly to be discussed if a single entity manages multiple installations, such as PV plants or large data service providers. But it will always be a software extension; it is not realistic that the development of hardware components (PLCs, I/O modules, sensors, meters, etc.) is worthwhile.
Supermarket chain, the Czech Republic
An important supermarket chain, operating more than 250 stores under its brand. During its operation on the Czech market, the company acquired one of the competing chains, thus increasing the number of branches. Over the last 10 years it has been gradually reconstructing its shops. In doing so, it unifies control systems so that it is possible to compare the energy parameters of the branches with one another and to evaluate outlets in which technology reconstruction or other energy saving measures would be worthwhile.
Thanks to its own intranet, which includes a separate technology network for building management system, commercial cooling and security systems, it was possible to build a central SCADA station. To work with it a full-time employee was employed, who continually checks alarms, sensor functions, differential pressures on air handling units, heating water pressures, etc. From historical graphs, due to operational experience, it is relatively accurate to determine the causes of failures or even preventively intervene even before a failure occurs (eg. a long-term drop in water pressure with periodic replenishment may indicate leakage of heating water from the system). The worker also solves the requirements from the helpdesk, such as setting the operating hours of the technology, switching times of lighting according to the operating hours, etc.
This staffing makes more sense than the training of store managers at each branch. They have many other concerns, do not have experience from multiple branches and when calling an external service company, they are not able to diagnose the fault as accurately as the headquarters operator.
Energy management, including data collection from meters, is currently provided by a separate system of a foreign supplier that has historical links to the chain.
Chain of discount stores, the Czech Republic
Similar situation as in the previous case, the chain manages about 180 stores throughout the Czech Republic. At the SCADA station, however, the operator does not sit permanently; the customer requests the transmission of alarm data to the energy management system. PLC and SCADA levels are thus basically used for data collection and alarm management. SCADA visualization is used only for setting of required values and time programs, branches are not regularly and systematically monitored.
Energy consumption data is evaluated – including benchmarking – so far manually using Excel spreadsheets, but the company is certified according to ISO 50001, Energy Management Systems (this only illustrates that energy management can be implemented with simple tools as long as the processes are thoroughly described and followed.). The plan is to introduce a ticketing system. Meanwhile, custom ticketing is used, with no connection to subcontractors. Several branches were implemented in the demo version of the EMS system and after evaluation of the trial operation the customer will decide whether he wants to connect other stores as well.
The operator of fast-food chains
An important foreign company operating four fast food chains with a total of more than 160 restaurants in the Czech Republic. For local control at the automation level in the plant, a lectern with an LCD display or a touch screen is used. The SCADA system is deployed at the headquarters in the form of a dashboard with an overview of the values of individual restaurants and active alarms. At the moment there is no employee dedicated to solving operational defects, but one technician is envisaged – he should – like the supermarkets in one of the previous examples – centrally address operational defects.
FIG. Map with active alarms in visualization
To measure consumption, foot meters of water, gas and electricity are installed, electricity is further measured by sub-meters for individual technologies – lighting, air conditioning, food cooling, kitchen appliances, etc. These measurements are stored in the database of the energy management system. The management of the company has a strong effort to reduce energy costs, for which value collection and detailed benchmarking are the first step. The EMS portal is operated by an energetic who was previously dependent on manual data collection and evaluation in a spreadsheet.
FIG. Dashboard with branch data
Manually or automatically?
Some activities performed by operators and power companies are routine. But is it good to leave them on the system, even if they could be algorithmized?
The typical task is tthe beginning and the end of the heating season. The heat supplier follows the algorithm according to the Ministry of Industry and the Regulation No. 194/2007 Coll. However, in individual buildings due to local loads, building orientation or operating conditions, the conditions can be programmatically adjusted in local weather-compensated control. In the transitional period it is possible to save several hours a day compared to the standard algorithm, during which the heating branches are completely shut down.
When monitoring, we most often meet the requirements for simple rules for monitoring whether temperatures or other quantities do not deviate from the permissible limits. In this case, it is necessary to correctly determine the time and tolerance window in which the error will be ignored to avoid false alarms. The mindful user will easily find other conditions and links whose combination he would like to watch. To a certain extent, this can facilitate the overview.
But the more the overall “health” of technologies is evaluated automatically, the more the operator relies on algorithms and stops thinking analytically. In the upcoming years, with the commencement ofzadání so-called artificial intelligence, we expect this trend to strengthen. Unfortunately, each program is just as good as it was programmed, and especially what instructions the programmer had. Therefore, a critical view of a technician familiar with the building will be a necessary condition for effective facility management for a long time.
Customer experience shows that it is very appropriate to divide the service into:
- the operational unit (to keep the equipment running while maintaining the required parameters such as temperature, humidity, lighting levels, etc.), and
- long-term (cost) management, which ensures energy efficient operation, but also optimizes the purchase of energy or other – such as service, revision etc.
At the same time, however, it turns out that the visualization or energy system should be built with regard to the staffing of the company so that it serves people and not vice versa. Therefore, the supplier should always first find out current and planned processes and their staffing and on the basis of this information only plan to deploy web visualization, local SCADA system, EMS, or possibly interfaces to existing or future customer systems. It is clear that each vendor offers some more or less configurable solution and, if possible, wants to modify it as little as possible. Seemingly banal adjustments can cost hundreds of thousands of crowns or be unrealizable within the system. These are mainly collecting and routing alarms, conditional reporting of non-standard states, data exports for foreign systems, etc. The ideal procedure is as follows:
- listen to the customer who will describe the current status and future requirements
- to contact him with customers who have already implemented the system and to exchange his experience with the operator who has been working with the system (or even its older version) for some time
- to offer the most advantageous solution based on standard elements of the assortment, possibly with adaptations, where time and financial demands can be well estimated
- to use experience from similar projects in the next round of negotiations and to inform the customer about critical points and risks
- after mutual agreement write down the specification in detail and have it approved by the customer.
It often happens, that the customer announces a tender and decides to prepare the assignment himself. There is a risk that none of the contractors will be able to fulfill everything 100% and the tender will be canceled or that the contractors will formally agree to the required functionality, but in reality the system will be somewhat different from the original ideas of the contracting authority. The solution proved to be to select one of the potential suppliers, who would then not participate in the tender, and to involve him as a paid consultant. The consultant can fully exploit his experience in creating a “feasible” assignment and, as an opponent on the part of the customer, he will be a strong opponent to his usual competitors.
Let’s expect that it will take at least six months to create the final version of the assignment, possibly longer if higher management levels are involved in the decision-making process (“board approval”, etc.). It often happens that the relationship with the supplier is longer than the functional period of the responsible persons of the customer. Then there may be a change in the requirements during the creation of the assignment or even a change in the assignment during the implementation of the project, which is already a justifiable reason for more work – if they are technically possible at all.
A deplorable situation arises when a developer or an implementation department of a company is building a building and, upon completion, submits it to (other) management company or operations department. In the familiar matrix, “my money, foreign money; I build for myself, I build for others” it is a combination where the client tries to reduce the investment costs despite the gross impact on the technical solution. At the beginning of 2019, for example, we were faced with a project in which around a hundred communicative fan coil controllers were designed, but which were no longer interconnected by a communication bus – In the half-billion budget there was no CZK 200,000 for cabling. This cost reduction dramatically reduces the utility value of the building and greatly complicates operation and maintenance, for example weekly programs would have to be set manually from each office, any defect would have to be checked on site without remote diagnostics, historical data would not be available, etc. While it is possible to measure energy consumption and evaluate key KPIs, it is difficult to find specific causes of bad conditions, such as erroneously set time programs, open hand valves (= unnecessary overheating) ) etc. Fortunately, the bus installation was successfully enforced and its advantages were already apparent during the commissioning of the building – gradually occupied offices, which were later complicated to access at a later stage, could have been controlled remotely.
The design and selection of the control room should therefore always be based on how and by whom the entire control system will be operated. Additional adaptation to user requirements is expensive and slow. It is therefore ideal if the end user is involved in the specification and selection process. But the question remains if the user is already known at the time the system is created.