Hello Everyone!

I am new here, but I have looked through the forums and done some research before writing this and I think I have a handle on what is involved. I just wanted to pick your brains on a few items before getting started.


We are a test and balance company and we deal with numerous controls systems (upwards of 15) on a regular basis. We do the best we can to have our guys trained on connecting and operating each system, but we are constantly running into communication issues and it is becoming a costly problem. The solution that we are proposing is to build a controls board in our office with multiple manufacturers / topologies. This should allow our technicians to verify that their computer can connect to a particular system prior to sending them to the job site. This would also allow us to avoid bugging the controls folks with random issues.


At the moment, I have ebay'ed 5 controllers that we use often: TAC MNL-V1R3, Carrier CCN VAV controller with Terminal board and actuator, Trane Varitrane UCM 4.2, JCI Metasys VMA-1420 and a Honeywell W7751E1007. I would also like to get a Trane Comm 5 board as well, but we don't really have issues connecting to those (for the most part).

Each controller will be setup independently and we hope to have actuators on all of them (those that don't have one built in that is). I was also toying around with the idea of hooking up an air pump with a pressure regulator to supply a pressure to the airflow tubing on the transducers at each board. That way our guys can see the airflow and calibrate the sensors and play around some more. Also, since the controllers are used, I believe most will have a program setup in them already so that makes life easier on us non-programmer types.

So that covers us for LON, CCN, and RS-485 comms on several different platforms.

My Questions:

  1. I need to work out a power solution for the controllers. Please keep in mind that I'm not very familiar with this side of things. Is it possible to use 1 class 2 transformer to power multiple controllers (not all of them, but 2 or 3) and are there any problems that may be associated with doing this? From what I understand, if the controllers have a load of around 20VA each, then a 40 VA transformer could supply 2 controllers. Am I thinking about that correctly? If so, how do I determine what the minimum VA load is for each controller? Would this come from product data / installation manuals?
  2. Does anyone have any tips or suggestions for what works best when building a board such as this?
  3. Does anyone have any photos of a board in their shop that I could reference (just to get ideas)?

Thanks in advance for any help!