Carrier RTU control via Bacnet

[brentstex]

We are looking at doing the controls at a facility under construction with 7 new Carrier 48A3E030 units that are supposed to come with BACnet communication capability. What level of integration is best? Read temperatures and data and then mimic thermostat connection or write setpoints and occupancy. The documentation seems to allow writing to many of the points as if controlling over the mstp network is expected. Has anyone had good success or experience with controlling these over BACnet mstp? What advice can you give. It seems that you need a Carrier tool to readdress the controllers. The application is mostly VAV zones.

[dracula]

If you are talking about the RTU-MP controls for I-VU Open, they are rock solid with
excellent documentation, "mapability" (BACnet), and very resonable training costs from your local distributer.

Depending who you distributer is, once you have had the training, you can buy the
"Field Assistant" tools, and then you can install, change out, configure them yourself,
if you are a qualified HVAC/Controls technician.

Tons of points and configureables available on the property pages, and you don't need to know programming to make adjustments, or troubleshoot.

Good documentation is available on line.

Anyway, hope this helps.

Drac

[brentstex]

I am sure they work well on a carrier network. This building will have carrier rooftops, boilers, VFD's, and VAV controllers on a BACnet network . So my question is, would you control these by network commands as you would a VFD from a third party BACnet system. Also what were the challenges encountered.

[drj_controls]

Make sure of the bacnet card installed, there are 2 flavors, the older 33CNTRAN485 and the new OPN-UPC, both will sit on a bacnet mstp network and take commands and setpoints, the tran485 is limited to 60 points where the UPC will have about 300 available along with some trending. The rooftop documentation should have the bacnet tables for the OPN-UPC.

[dracula]

I am sure they work well on a carrier network. This building will have carrier rooftops, boilers, VFD's, and VAV controllers on a BACnet network . So my question is, would you control these by network commands as you would a VFD from a third party BACnet system. Also what were the challenges encountered.

Yes you can use "network commands", but understand the design limitations, and practical issues with doing so, entire different conversation as to how far "network commanded" controls should go.

It sounds like you may have some experience, as you are asking the right questions.

My answers are biased towards the "end user" or "building owner" point of view, so some control contractors, and engineers, may not completely agree with my opinions.

First off, do not use or allow the earlier Carrier BACnet Translator boards to be used on your projects, it is not fully compliant with todays most recent BACnet standards, and BACnet points mapped thru them will have trouble binding.

Second, specify "Ivu Open" product line by Carrier, if Carrier is what you select. The new Ivu Open stuff is made by ALC's OEM division, and has very robust capabilities of playing well with other BACnet brands (VFD's, Boilers, AHU's, and lighting controls) all on the same system.

OEM Controls makes controls for most of the "best of class" equipment systems in the USA that have integration capabilities, from boilers, to chillers, thru AHU's. By the way, I do not work for ALC, Carrier, or OEM; I work for mostly owners, system end users, and a slected few very high quality controls contractors.

Biggest question you project needs to address is how much the "owner staff" is going to interact with the system. I have designed for building owners that "just want it to work, save money, and "no hvac complaints", to owners that have very well trained building engineers, that once the base system is installed, their in house staff expands, and amplifies the system, with the installing controls contractor only providing support as needed.

This makes a big difference in which controls brand, and more importantly which controls contractor you select, second to pricing.

Some BACnet brands, and their associated distribution partners (controls or mechanical contractors) focus on end user satisfaction via long term relationship building and support, and then you have 98% of the rest that want to sell low, put it in, get out, and never hear back from you.

There are BACnet brands that have amazing graphics, reports, and slick as heck sales brochures, none of those count much, as reports can be done better outside of the BAS system, without paying extra, fancy graphics are meaningless, if the systems doesn't work well, and the glossier the brochures the more caution as chances are they are spending more on marketing then customer satisfaction.

It also sounds like you are investigating the posibility of making use of BACnet to have a fully integrated system. With that in mind, I recommend that you bring in a professional and experienced "BACnet" system integrator early on in your project development. I also recommend that you select one that is not directly representing any particular automation system brand.

There are extremely few mechanical engineering firms that can handle multiple system integration, so let the ME's do the physical design work but definately bring in a SI for the controls side of the project.

As far as concerns with the new Carrier;

Front end is a small PC server, current version can not be installed onto your own server. (susposedly this will be resolved in a furute release)

You can't create the system database in advance, you must have all controllers powered up and on the buss, than you discover all of the devices, and then you customize your system. (Many BACnet manufacturers are going this way today, so it is not a real proble type of issue)

For old timers like me, it does take some getting used to as I usually like to have the system design done and tested before the controllers start up day.

Other than that, you should do fine with CArrier Ivu

Respectfully

Drac

[brentstex]

Thanks for the comments, great help.