Building Automation System Integration Challenge LinkMaster + TOP Server + INGEAR OPC = Problem Solved The Challenge: A Building Automation Supplier was installing a system for a large medical lab. The system managed lighting control, HVAC control, security systems and more. The project required there be a touchscreen interface on each of floor in the facility. From each touchscreen, the user needed to be able to access data for not only their floor, but other floors. Budget constraints meant the system had to be done as economically as possible. The Solution: Because the building was already wired for Ethernet, it was easy to obtain an extra network jack at each panel. The building automation system provided an OPC server interface as a means of moving data into and out of the system.  To move data between the remote panels and the building automation system, the integrator chose to use open Modbus TCP Ethernet protocol as a fast and efficient means to communicate from the panels back to the Building Automation System over the existing Ethernet connections. On each floor, a Siemens Windows CE Multipanel was installed running an application using Siemens ProTool HMI software and an INGEAR Modbus Ethernet OPC server. Back at the Building Automation System, the user installed a copy of the TOP Server Modbus Ethernet Slave driver and the LinkMaster OPC to OPC bridge. LinkMaster maps all necessary data from the Building Automation System to the Modbus Ethernet Slave. Each remote panel reads/writes data to/from the Modbus slave using the INGEAR Modbus Ethernet OPC server.   So how does it work. Lets look at some examples.  Remember all these steps are happening in sub-second time over switched Ethernet. Writing Data From the Touchscreen to the Building Automation System When the user wants to write a value to the building automation system, the HMI software writes the data to the INGEAR Modbus Ethernet OPC server, which in turn writes the data to the TOP Server Modbus Ethernet Slave. The Modbus Ethernet Slave automatically notifies LinkMaster of the new value, and LinkMaster in turn writes the data into the Building Automation system's OPC server. Reading Data from the Building Automation System and Displaying it on the Touchscreen When values change in the Building Automation System, the Building Automation System OPC server automatically notifies LinkMaster of the new value. LinkMaster notifies the TOP Server Modbus Ethernet Slave of the new value. The INGEAR Modbus OPC server on the Touchscreen is periodically polling the slave for new data – as soon as the new data is received, the INGEAR OPC Server notifies the HMI application which updates the users screen. Conclusion: For the user, the solution built with tools from Software Toolbox provided the results the client desired at an affordable price, with an open, standards-based solution providing the desired level of performance. No closed or proprietary hardware was used in this solution, which gives the user the investment protection and future flexibility he desired.