For any of you who may have jobs coming up that call for integration of the FX60 to Lennox Prodigy Controllers via BACnet MS/TP, here is what we ran into on our first job (thank heavens in was a small job).
- Items to be aware of with Lennox Prodigy / BACnet:
- All points that are imported are either AI, AV or AO. This is a source of extra work as you have to make a table for the graphics to alert the user as to what the value reported actually means, example: fan status = 0 or 100% not on/ off.
- The controllers are not Peer-to-Peer.
- The BACnet ID (instance) is the same as the MAC address (1-127)
- Lennox is a two wire communications bus and must be brought to its own dedicated RS-485 port. Lennox calls for the installation of a 22/2 twisted shielded cable. They use the drain wire as earth ground via their "G" terminal on the communications plug of the controller. You will need to terminate the bus using a 120 ohm resistor at the last device. At the FX60 take the drain wire to ground.
- Set you baud rate at 38400 and on the network port assigned to this equipment set your poll rates to: fast poll = 15 sec, normal poll = 25 sec and slow pol equal 30 sec. You also need to set your "Max Frames" setting to "1" as the controller only support "Max Frames" as "1". The default setting of "20" in the FX60 will cause communications errors and false values to be reported such as upon adjustment of set point you will get "write denied - value out of range".
- You will also need to create the following tuning policies:
- TOD-Tuning-Policy - for writing time of day commands to the OccScheuler of the controller the value from the schedule must be as follows - min write time 4 minutes / ma write time 6 minutes.These values are per Lennox factory technical support.
- Set Point-Tuning-Policy - all occupied / unoccupied heating and cooling set points as follows - min write time 2 minutes /max write time 3 minutes. These values are per Lennox factory technical support.
If any one has any questions feel free to reach out to me. If you can get with your mechanical contractor and see if you can attend a local training session on Prodigy. It is well worth the time.