South African automation specialist Abacus Automation was in July approached by a natural gas supplier, which requested that Abacus provide a solution that would allow the supplier to conduct remote monitoring of its customers’ sites.
Prior to the implementation of this solution, the customer telephonically relayed information to decide how to coordinate gas delivery. Issues that resulted from this telephonic system ranged from no feedback after working hours to incorrect feedback owing to human error.
To address the problems of the outdated telephonic system, Abacus’s solution needed to accommodate three critical requirements, namely traffic volume, client security and supply chain connectivity. In other words, the solution had to cater for multiple users, situated at different points in the country, simultaneously loading queries onto the system for information (volume), while maintaining strict end-user segregation that prevented other end-users from viewing data that did not concern them (security), all the while facilitating the reliable transfer of data from end-user sites to the supplier (supply chain connectivity).
Abacus, as an implementation partner of electronics giant Siemens, decided to make use of the Siemens Simatic automation components for the framework of the solution. “While certain Siemens programmable logic controllers can present process data using a built-in Web server, the development of multiple Web pages for a complex process can sometimes be cumbersome and is limited in certain aspects,” says Abacus project engineer Dhiren Naidoo.
He notes that the Siemens supervisory control and data acquisition (Scada) products are the more robust solution to this limitation as they provide a Web-based interface in parallel with a regular Scada interface.
“This aids in development, cutting down on the time required, as well as duplicate configuration. “The solution also leverages the tried and trusted Internet Information Services built into Windows to provide a reliable software framework for the Web interface,” says Naidoo.
As the solution is HTML5-based, the generated Web pages also scale well between smartphones and computers. Siemens Scada also provides easy segregation of information and security management by authenticating users when presenting the Web page equivalents. This met most of the data presentation requirements for the customer. Ultimately, this means that the end-user does not require specialised hardware or software, embracing the ‘Bring Your Own Device’ paradigm with minimum development effort on Abacus’s part as the system integrators.
The remaining challenge was to gather data at more than one end-user site and display this information on the Siemens Scada. Siemens communication protocols proved robust enough to work over routed networks and were, therefore, chosen to maintain regular data transmission from end-user sites to the customer’s main facility.
The initial proposal for the solution placed the responsibility for the physical data links on the customer’s information technology provider. While this was the ideal arrangement, complications later arose that allowed Abacus to provide a connectivity solution as well.
After the proper security precautions had been taken, data links were set up between the customer’s premises and the end-user sites using popular, lightweight routing hardware through ADSL with 3G failover. It also provided access to the Web server at the customer premises, for those with the appropriate credentials. For security reasons, in this implementation, no control is allowed through the Web interface, despite the solution being perfectly capable of providing this functionality.
“Although Abacus rose perfectly to the challenge of providing a connectivity solution for the customer, it is recommended that the data link be handled by a company that provides connectivity as a service, benefiting both the systems integrator and customer in that their data link is guaranteed to a measured metric, be it uptime or bandwidth,” concludes Naidoo.