View Full Version : Lennox BACnet module
04-25-2009, 12:18 AM
Wondering if anyone has had any issues with Lennox's BACnet module for the M1-7 IMC? I have a couple of units that will communicate for months with no problems, and then all of a sudden..... I can read their points, and it is giving me an error code 93"the control has changed the system mode because of an error with controlling sensor or because of a loss of comm"
Just to be clear that I don't believe it is a wiring issue, as one unit is in the middle of the network, the other is on the end (of the actual network wire, not address). Using Reliable controls on the rest of the building, as well as the OWS, the lennox units are on a sub-net, not my main-net.
The M1-7 has firmware version 5.23, anybody have any issues? I see that Lennox has switched to an M1-8 IMC, and have a new BACnet module available, could it be because of issues? Units are just over a year into service :(
Any insight/help would be greatly appreciated.
04-25-2009, 04:40 PM
are you sure the service guys aren't playing around with the button in the imc board ? had similar issue with the lon version.
04-27-2009, 11:24 AM
Earlier versions of the M1-7 Bacnet Module were susceptible to "locking up". These issues were fixed in modules that are marked: BACnet MSTP V1.15j, LENNOX V1.03m.
If you have the latest version, I would look at the network for your problem. The 93 error is a symptom of the module not receiving the necessary messages within a certain period.
If the module is not the latest, get an updated module or replace the M1-7 with an M1-8 and the new M1-8 Bacnet module.
The M1-8 version of Bacnet is your best bet. It has improved reliability and has some added features such as it supports multiple baud rates. (I was involved with the initial field testing of the M1-8. It seemed to resolve of lot of integration issues involving network responsiveness.)
04-27-2009, 10:40 PM
Thanks for the input,
I think going to the M1-8 might be my best bet. I have switched the BACnet modules around (took the ones from the units that worked), and so far so good. I am going to hold off replacing anything for now, and see if the problem occurs again, and if it follows the BACnet module or stays with the RTU.
It's great to know that people are around to help you out, thanks again for the input.
04-29-2009, 08:54 AM
I think going to the M1-8 might be my best bet.
You're right on the money. The M1-8 has by FAR better reliability than the M1-7 - BACnet board combo.
I have switched the BACnet modules around (took the ones from the units that worked), and so far so good. I am going to hold off replacing anything for now, and see if the problem occurs again, and if it follows the BACnet module or stays with the RTU.
We've had a good bit of exposure to M1-7's and M1-8's. The BACnet board swap will work for a little while, but it will also go out. Also cycling power on the RTU to reset the BACnet board will work, but for maybe a few days to a week. Your best bet is definitely the M1-8's.
06-08-2009, 08:21 PM
You nailed it, the swap worked for a while, M1-8 is getting ordered now. I don't imagine that I will have communication issues between the M1-8 and the M1-7 boards, but if anyone has any experience with this, insight would be great. I think it might be hard for me to get all new M1-8 boards as this should still be under warranty.
06-09-2009, 10:48 AM
I don't imagine that I will have communication issues between the M1-8 and the M1-7 boards, but if anyone has any experience with this, insight would be great.
As long as you have a M1-7 on a loop, it has potential to take down com to the entire loop.
If they are not yet exhibiting bad behavor, and it is passed the one year warranty, you may have some issues getting them upgraded to M1-8 now. You may want to inquire if they will honor a swapout if/when they go bad.
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