Issue
Capability to import a BACnet device objects via an EDE file?
Product Line
EcoStruxure Building Operation
Environment
StruxureWare Building Operation site with BACnet
Cause
Questioning if StruxureWare Building Operation has the capacity to import a BACnet device objects via an EDE file?
Resolution
We do not support importing from EDE files.
We would like to have a good solution for pre-engineering 3rd-party BACnet devices. This is a problem that R&D has looked at on several occasions. The Engineering Data Exchange (EDE) concept is one way to address this issue. Although the BACnet community is in favor of solving this problem, they are not aligned on using EDE files as the solution. The EDE file concept was introduced through the BACnet Interest Group Europe (BIG-EU) by Siemens as an attempt to mimic LonWorks functionality. For worldwide adoption it must become an official extension to the BACnet standard as an approved addendum via the ASHRAE BACnet committee SSPC 135. The BACnet committee has reviewed the EDE file concept and feels that the solution does not fit in with the BACnet roadmap and is not technically ideal. The EDE file is a CSV format and the BACnet committee favors a more modern standard that has extensive self-describing features such as with XML or JSON. For example, BACnet Electronic PICS (EPICS) and BACnet Web Services is XML based and their is an active XML Working Group within the BACnet committee. We understand the BIG-EU is looking to ASHRAE for guidance on this issue and would like to be aligned with the standard going forward.
There is a deeper issue beyond adoption by ASHRAE and the technology choice. The reliability of the EDE file cannot be guaranteed. The BACnet Device and Network IDs and objects contained within must be set exactly in the EDE file or configured offline to match the actual device in the field. If these BACnet addresses and objects don't match you will most likely end up with major problems when the database is brought online. Packet captures will reveal duplicate messages and excessive network traffic and references will fail to work. EDE Files for application specific (ASC) devices are likely to have a longer shelf life then EDE files for free-programmable building controllers. However, if an ASC has it's firmware updated, even an ASC EDE file will become outdated and useless. It is rumored that EDE files have been used successfully in the field but want to point out that this is not a fail-safe method nor is it tested and supported.
As we continue to participate in the ASHRAE BACnet working groups, we will activity engage ourselves in the pre-engineering solution discussions. Our hope is that a universally accepted solution that can address most of the concerns can become an approved addendum to the ASHRAE BACnet standard.
It turns out that the ASHRAE BACnet committee is further along than reported above. ASHRAE 135-2008 Addendum which added the XML file formats to the standard addresses this application: http://www.bacnet.org/Addenda/Add-135-2008t.pdf
Looking at the rational section of this addendum you will see a list of the intended applications:
This syntax is intended to be the core data representation for the following use cases:
- An electronic version of a PICS document, consumable by workstations and other tools, to describe the capabilities of a device.
- An XML version of an EPICS, defining not only the capabilities of the device, but also including the complete test database and other test-oriented data.
- An "as built" description of a deployed device, distributed either as a separate file or as a File Object resident in the device itself.
- Descriptions of proprietary objects and properties and datatypes (in any of the above three uses). These descriptions may be minimalistic, providing basic data sharing capabilities, or extremely rich, providing complete descriptions of the meaning and usage of the data to enable a comprehensive user interface, including the capability of providing such descriptions in multiple human languages.
- An export format for tools and workstations to export or publish their knowledge of the arrangement and configuration of a device or a complete system of devices and networks.
- Web services that exchange complex or constructed data
With an official ASHRAE BACnet solution it is just a matter of determining which method to go with.
Despite the format, it is possible to have a utility application that can automatically generate an export file. It would even be possible to convert an EDE file to XML. Albeit, I believe the EDE file would be less descriptive then an XML file generated from the actual device. It may be better to natively import via XML. We would then either get a BACnet XML file from the vendor or have a small external utility gather from the live device or convert an EDE file.
