## 4 Results
### Clearing of SICS Services  
If you want to offer PLC functions as smart services or control as a service (CaaS) in the context of a business model, you have to create interfaces and make them transparent and open, in order to give third-parties the opportunity to connect their business models to these interfaces  
In the IC Industry, this has already been standard for some years and is being used with a strong upward trend. In the classical automation industry, these service models are so far largely unknown or, for various reasons, difficult to implement or even unwanted.  
What does this look like for PLCs as smart services, according to the SICS concept?  
1. The PLC functionality as a service with disclosed and well-defined interfaces is available with the SICS controllers.  
A third party may integrate and offer the SISC services in his cloud system or IoT system (e.g., FlexIOT).
* For implementation as a business model, however, the SICS services must now also be able to be settled appropriately.  
The implementation of topic 3 requires special consideration, since previous SaaS systems (including various IoT platforms) charge IC services very differently.  
For automation services (control systems, HMI, SCADA, alarm monitoring, etc.), business models make sense from the point of view of future globalized, convertible and digitized production, which can bill individual services on a runtime basis. Since machines and stations normally are not permanently operated with all available functionalities, a billing after runtime significantly improves the cost-efficiency of the user, and also ensures a cost transparency of the services used.  
So far, the authors, however, do not know a system in which automation services can be billed on runtime basis. Most billing is done with a flat rate and/or according to the number of integrated devices and/or transmitted data volume. One reason for this is certainly that on one hand, in the usual server-centered systems a customer and service-specific runtime determination within the server is very expensive and on the other hand, the runtime of services in the field of IC plays rather a subordinate role.  
For the settlement of the SICS services, a clearing system has therefore, been developed for the FlexIOT platform (FlexIOT Service Portal) with which the service's runtime can be determined and settled, at least for a SICS SMM controller.  
The clearing system runs independently of the FlexIOT portal and uses its own database for the billing data. Figure 13 illustrates the basic structure of the interaction between the FlexIOT portal and the clearing system.  
In RUN mode of the FlexIOT portal, i.e., if a user uses a configured FlexIOT functional system (for example, a SICS control function or an HMI panel), the runtime measurement of the FlexIOT services in the clearing system takes place via a ping-pong mechanism. The services can be analyzed in detail in the clearing portal and settled via PayPal. Detailed information about the clearing of described smart services, you can find in [17]. The clearing portal can be tested online on [[http://www.flexiot.de:3000](http://www.flexiot.de:3000)]([http://www.flexiot.de:3000](http://www.flexiot.de:3000)) and uses the same user accounts as the FlexIOT portal.  
Figure 14 shows a part of the billing/analysis webpage in the clearing system for a sample project of a user in which 5 SICS-SMM controller instances were used for several minutes. A total of 106 process datums from an automated station were connected to the SISC controllers.  
Figure 13: Basic structure of the interaction between the FlexIOT portal and the clearing system.