PLC BACnet, ARCnet

[euuil]

Hi all,

I have project to connect PLC (brand Mitsubishi/Nais/Siemens)to BAS (building automation system) controller over BAC-net or ARCnet. I understand some PLC has open protocol such as Modbus, profibus, or device-net. Is there anyone has any idea how to link PLC protocol to BAC or Arcnet.

Thank's in advance

 

[BobB]

I have used BACnet in a SCADA system but not a PLC. Good luck. It turned out to be a nightmare and at the end of the day we found the BACnet hardware was not compliant with the standard. I used a driver from Cimetrics. Here is a link to their website Cimetrics

The driver I used runs as an application layer on an Ethernet network. It is quite slow for PLC people. Uses change of state but takes ages to get going. I guess it is fast enough for BAS.

Here is a link to the BACnet website BACnet website

I guess if you were able to get the specs you could write a driver in an ASCII card but I believe it would be quite painful and time consuming. When the BACnet people cannot get it right it makes you wonder.

I do not know of a PLC that supports BACnet. Honeywell would perhaps be the best bet as they do (or did) belong to ASHRAE. They are the ones pushing BACnet. I think you would be better off attempting to communicate with the BAS with Modbus, if you can. At least it is fairly standard and we have just about all used it somewhere.

Good luck!!!!!!

beerchug

 

[Lancie1]

euuil,

Take a look at the ALERTON VLC models of PLC, at this site: http://www.alerton.com/Products/default.asp

They use a BACnet network protocol called BAC-talk, and are specifically designed for building Heating, Ventilation, and Air Conditioning (HVAC) control. Each of the "VLC's" comes ready to connect to the 2-wire BACnet cable, with no other equipment or interfaces needed.

 

[BobB]

Alerton are the hardware devices that we found did not comply with the BACnet standard. They now have tested devices listed and since the hardware on site was replaced with the tested units, there have been no communications issues at all.

I do not think that the BACnet hardwae is really a big issue for euuil at this stage but communicating with these devices from a PLC is going to be the problem. That is the reason I mentioned Honeywell as they are members of the association and may have a PLC (sorry, they call them controllers not PLCs) interface module available. Never thought I would be mentioning Honeywell as a possible source of PLCs. First time for everything.

I quite like this smiley Eric Nelson. Perhaps does not accurately describe old timer's disease but certainly good for my "Old Pfhaart" image and status.