New Release of S4 BACnet-N2 Router This document will walk you through the user interface of 1.30, highlighting the new features and summarizing some of the existing features to assist in system installation and configuration.

Steve Jones, Founder and Managing Partner The S4 Group Inc

In recent discussions with Ken Sinclair he suggested that we have been way too quiet. That’s true. For the last year+ we have been focused on major Release 1.30 of the BACnet-N2 Router. That was an all-consuming effort that required a lot of focus and all of our available resources. I committed to Ken that I would provide an update on what we have been up to, so here it is.

Release 1.30 of the S4 Open: BACnet-N2 Router and S4 Open: OPC-N2 Router added many significant feature enhancements, performance improvements, and bug fixes to the core S4 Open appliances and S4 Open: Management Console. Many of the enhancements are BACnet specific; however, enhancements and bug fixes to the legacy Metasys® N2 integration and core services apply to both BACnet and OPC products. This version started shipping with all new product orders starting in January 2016. Existing customers with an active Software Assurance program subscription are eligible for an upgrade under that program.

This document will walk you through the user interface of 1.30, highlighting the new features and summarizing some of the existing features to assist in system installation and configuration.

System Level BACnet Settings

These features apply to the N2 Router itself. The Appliance acts as a BACnet router and needs to identify itself to the BACnet enterprise with the BACnet Network Number that it will reside in and its own unique Device ID. The BACnet-N2 Router can serve as a BBMD for the local IP subnet or register as a BACnet Foreign Device to the BBMD in another IP subnet.

Customizing the BACnet Environment

These enhancements allow you to configure the features, services, and options enabled for the publishing of virtual BACnet devices to BACnet/IP by the S4 Open: BACnet-N2 Router. By default, all features, services, and options are enabled.
BACnet COV support is new for this release. Enabling BACnet COV causes the S4 Open: BACnet-N2 Router to advertise support for both Unconfirmed COV and Confirmed COV services. Subscriptions to these services are initiated by one or more BACnet clients.

Transparent BACnet Caching is a new S4 Open Appliance service for 1.30. This is an S4 Open: BACnet-N2 Router feature (not a BACnet service) that disconnects the operation of the N2 field bus from the BACnet transaction stream submitted to the BACnet/IP interface. This feature dramatically improves BACnet client performance, and the user experience, by responding to transactions almost instantaneously. Behind the scenes, the S4 Open: BACnet-N2 Router schedules subscriptions to this service, manages the field devices, and maintains data values in the cache. With the introduction of Transparent Caching it is no longer necessary to add extra time to the BACnet client APDU Timeout and Segment Timeout to accommodate the round trip time to retrieve data from N2 field devices. This feature should be disabled only for diagnostic purposes at the direction of your distributor or support contractor.

Live Point Monitoring

Live Point Monitoring option is a global option for the Management Console. Previously, there were no properties on the S4 Open: Management Console node of the navigation structure so be careful not to miss this option.

This option applies the Live Point Monitoring display of all devices in the Building Control Network on all S4 Open Appliances displayed by this management console.

Live Point Monitoring uses BACnet COV, BACnet Polling, or native Windows DCOM communications to request data values from the field devices, with precedence being applied in this order. By default, BACnet COV is disabled and BACnet Polling is enabled for most efficient operation. On the BACnet Tab, you have the option of disabling the use of any of the BACnet access methods if you desire. If all BACnet methods are disabled, native Windows DCOM communications will be utilized.

These options only apply to the Live Point Monitoring feature of the S4 Open: Management Console. This feature is implemented as a BACnet client and is independent of the BACnet Operator Workstation or BACnet global controller selection of access method. i.e. The S4 Open Management Console could be gathering its data by BACnet Polling and your BACnet OWS can simultaneously request data by BACnet COV subscription (either confirmed or unconfirmed COV; both are supported).

If enumerations are defined for Boolean (On Text / Off Text) or Multistate points (State_Text) the points will be displayed with their evaluated states instead of using the numeric value for the point. The Present Value column in the point detail pane will be displayed only if Enable Live Point Monitoring is selected.

The BACnet OID column is new and always displays the BACnet Object Type and Instance Number for the point. With this release, BACnet instance numbers are coded in the associated Device Template and will not change unless explicitly edited by the installer on the BACnet tab of the point properties page, or in the associated Device Template.

The content of the point detail pane can be conveniently exported to a spreadsheet using the right click “Export List” option from the device folder in the navigation pane.

What’s In Your Configuration?

The new configuration tab provides a summary of the current configuration discovered or loaded into the N2 Router.

A new Optimize feature deletes device templates not assigned to any device from the catalog freeing up valuable memory for operational functions.

Smart Data Points

Smart Data Points are a generic capability that can be utilized to perform almost any data transformation during the BACnet (or OPC) read or write process. They are implemented using a combination of Virtual Data Points i.e. points that have a presence only in the S4 Open Appliance and a JC BASIC-like scripting language that enables you to apply algorithms to underlying native N2 points. These algorithms are triggered by the BACnet (or OPC) Read and Write requests to the Smart Data Point. These points are published to BACnet (or OPC) and are indistinguishable from the native N2 points in the client interface. With this capability you can give the published device a personality much different than that of the underlying native N2 device.

Customizing BACnet Virtual Device / Point Attributes

Engineering Units can now be specified for Analog data points. Selection of Units can be made by clicking on the Units link and navigating to the desired enumeration. This selection is independent of the configured Metasys® database and is published to BACnet using standard Engineering Units codes.

For Boolean or Multistate points, the On Text and Off Text and State_Text can be specified or edited by selecting Enumeration in the Units link and then specifying the desired states.

Multistate points are supported using Smart Data Points in the Device Template for N2 devices.

New Device Template Catalog

Default values for the BACnet Name, On Text, Off Text, and State_Text, and Smart Data Points are now included in the S4 Device Template definitions for 1.30.

Creating Unique Device IDs for Virtual BACnet Devices

The Configure Wizard discovers devices on the N2 bus, creates corresponding Virtual BACnet devices, sets up routing tables, assigns Device Templates, and initiates Publishing to BACnet/IP. By default, the N2 address of each discovered N2 device is used to generate the BACnet Device ID for the corresponding Virtual BACnet device.

Release 1.30 Wrap Up

This release prepares the S4 Open: BACnet-N2 Router and S4 Open: OPC-N2 Router for enterprise level, complex integrations with high point count and data rate requirements. It also prepares our S4 Open appliances for supporting several new integrations by implementing many of the concepts outlined in ANSI/ASHRAE Addendum al to ANSI/ASHRAE Standard 135-2012 Best Practices for Gateway Design.

Future Directions

Both major releases 1.50 and 2.0 are just around the corner. Release 1.50 is a migration of the 1.30 firmware and functionality to a new operating system, Windows Embedded Compact 2013, on our current hardware platform to improve system security, improve code portability, migrate DCOM interfaces to web services, and provide new system services required for major enhancements planned for release 2.0. We encourage Automatedbuildings.com readers to contact us with suggestions for future enhancements or additional legacy system integrations.