Modbus to BACnet mapping with predefined maps

by Svetlana Lyons March 25, 2013

Cimetrics' B6030 requires no mapping from the user (think of countless hours one can save without doing manual mapping). It comes with already preloaded maps. In this blog post we will describe how the maps are configured.

Our maps take every useful Modbus variable, and compositions thereof, in a device and associate it to a BACnet object. The map is nothing more than taking the manufacturer’s register map and transferring to the internalized template. Cimetrics has done all that work upfront for you in the B6030. Plus we have used our knowledge of the best names and units and conversions for the domain.

Keep in mind that our map does not allow you to select which of the variables the B6030 will poll. Many Modbus devices have hundreds of variables. Modbus power meters, for example, can have hundreds of registers, and some of them are composites or scaled by other registers or based on setup bits on yet other registers. You only want to poll for a limited number of variables - namely the variables of key importance to data consumers in the BACnet domain. Knowledge of the domain is the key. How many users really want to know the Nth harmonic of each voltage and current phase? The number of such users is exceedingly small and these values are oft better interpreted by other devoted systems. Limiting the scope of the polled variables and making the set consistent throughout every deployment (as well as names, units, etc.) is accomplished by DEFAULT in a B6030.

The maps are inside B6030 – you do not have to download them from a site or pay extra. If you do not see the template you need in our template list please email to support@cimetrics.com inquire about the development of a map for your and other’s use. Also, please free to send your questions or comments about this blog post. We value your opinion.

Although manual mapping can seem easy, it can lead to issues like

massive mapping inconsistencies between different installers.
questions about what to do when devices are added to your network.
questions about how to deal with device moving to a new IT subnet.

We say you should not have to do any of the things. You should have to do nothing complex at all beyond:

setting up an IP address
accepting some best practice defaults
enjoying intrinsic domain knowledge and best practices
enjoying consistency of deploys no matter who installed the BACnet to Modbus “map”
meeting your goals
imagining the possibilities