Carrier Modbus CCN to KMC Bacnet integration.

[ControlTech123]

Hi All,
I have a bit of a integration problem. Here is a email I sent out the other day.

I could receive some information from the Carrier Chiller CCN and it didn't make sense. For example: There leaving chilled water temp register would always report a 38 regardless of what the chilled water temp was. This is the setpoint. I felt like I was doing everything correct. I ended up looking at the documentation that came with the Chiller. There was a factory check out certificate. It listed the CCN software version as CSA-SR-20C460400. The register list I received was for Software # CSA-SR-20C460104 & 46017 & 46019 dated 2/24/2006.

Now I'm being told from the local Carrier folks that the software version doesn't matter. Does anyone have any insight. Does anyone have A register list for this software version. The integration is definitely communicating. I can't start/stop the Chiller and most of information I get back does not make sense. Some of the registers won't bring back any data.

Thanks,
Jim M

[adrianfromoz]

Your'e problem may be that the address you are using is out by one. For example the client device may have its address map start at 1 but the master device assumes a base of 0. This is a problem that I have come across from time to time when doing a Modbus integration.

Regards
AdrianfromOz

[Ausccn]

It depends what points have been mapped from the chiller. Were you given a list of what CCN points are at what address e.g. AV's & BV's ??. The interface defaults to auto map which means that when connected to the chiller the interface will automatically read into its database the 1st 60 points that it can find.

This can also be overridden and points can be manually mapped. If you are reading the setpoint instead of the actual temperature then it sounds like the address mapping that you have been given is incorrect!!.

Aus..