Aerco BMSII comm problems

[Igotworms]

I have a building with a bunch of N2 controllers with an NAE. There is also the XPC gateway to communicate to the Aerco BMSII controller with 4 aerco boilers communicating with modbus. I want to be able to reset the aerco boiler setpoint based on outdoor air. I was able to get all the points to read back at the NAE a few months ago, so I know the communication reading for N2 to Modbus is good. What i want to be able to do is write to the setpoint on the modbus side thru LCT. Im writing to the BMS point "net header setpoint" since it is the only one I am able to write too. Once I cycle power to the BMSII, everything is fine for about 2 minutes until I get " Modbus comm fault" on the BMSII. I tried changing the COV Increment at the NAE for both, the outdoor air temp and the aerco point. The aerco book says that error is bacause is does not write to the BMSII fast enough. Has anyone ran into this before?

[Cagey57]

Call Aerco Tech Support and ask for Desmond. He Is "The Man". You need updated clipping files.

Search for a similar thread about august/sept., more info there.

[Igotworms]

I talked to him before back when i couldnt read any points. I think i have the latest clipping files from the last time i talked to their tech support. also the rep was with me and he wasnt sure how to solve the problem either. ill ask about the clipping files though.

[Igotworms]

I think i need to send the signal faster. Will changing the "COV Increment" under the point in the NAE send it faster?

[Cagey57]

Igotworms,
the one I worked on was a BMS. I don't think it was a BMSII. The problem I had was the XPC would work for 4 minutes (after power up) then default to the programmed fail safe setpoint.

What I got from Areco was a revised clipping file and some new "dohickey" for the apploaded that kept the "Setpoint" active ! If I remeber right Desmond sent me 2 or 3 files, 1 of which I had to download to the XPC (I think) so that the XPC would maintain the signal to the BMS.


The "ModStat" was a big part of it but that was last october. The local Areco tech was like a Genius on the BMS so that helped a ton. All I really remember was that the ModStat was a critical part .

To answer your question about the COV, no ! Won't make a difference on the XPC side.

All of the XPC stuff was dated 2007 and all the new files Desmond sent me were 2009.

That's all I can recall. I bet I spent about 6-7 hours fighting it until Desmond sent me the right stuff.

Are you writing to the XPC from a reset LCT or sending an analog signal. Mine was done by writing the output of a span block I think ?

[Igotworms]

Igotworms,
Are you writing to the XPC from a reset LCT or sending an analog signal. Mine was done by writing the output of a span block I think ?

Yes, all I am doing is using LCT with a span block to reset the BMSII setpoint with the outside air. I remember downloading a clipping file but that came with the BMSII, so im not sure how old it was. I will give that guy a call though. Thanks for the help

[justjohnson]

The XPC communicates to the BMSII using Modbus. The BMSII needs the Net Header Setpoint re-written to it within the timeout period regardless if it has changed, (I think it defaults to 2 minutes) or else it will revert back to the default header setpoint in the BMSII. The XPC should be doing this, like CCIKelly said if it's not you need an updated firmware file for the XPC. I've done two with direct modbus interfaces and I had to do it in programming. The last Aerco setup I got came with an XPC and it's been running fine now for 6 months.

[Cagey57]

FWIW,
According to Aerco, If the XPC comes as part of the factory package you (we) are supposed to have no problems. If it (the XPC) is field installed and setup the factory has basically done nothing to it. Which mean we get to fool around with it for WAY TOO MUCH time.

As justjohnson, said the BMS needs that signal re-sent before it times out. The new files I got for Desmond fixed everything. Once I had the new "Stuff" it only took 15 minutes and Bam ! Work good, Last long time !

[Igotworms]

I got it to work. The gateway came with the old clipping file in it. Once i got the updated ones i downloaded it and it worked fine. Thanks for all the help

[Cagey57]

Igotworms,
Congrats ! You are now offically an Aerco XPC expert !

[Igotworms]

Is it possible to override a boiler off individually through the Modbus gateway? I talked to tech support about it and they said that it couldn't be done. Im trying to avoid having to run new binary outputs to each boiler.

[Igotworms]

CCIKelly, did you have to override the boilers off when you were dealing with this gateway? If so, how did you do it?

[freddy-b]

Is it possible to override a boiler off individually through the Modbus gateway? I talked to tech support about it and they said that it couldn't be done. Im trying to avoid having to run new binary outputs to each boiler.

I think you are SOL.

These boiler manufactures really need to pick it up a level or two with their BMS interfaces.
I will say Aerco tech (as it deal with controls integration) is further along than hydrotherm.

Call them and let them know. Also, don't you think that manufactures should throw in a palette of relevant graphics with the sale.

[Igotworms]

Yeah I figured I was out of luck. But what really peeves me off is the engineering firm specd these boilers with the factory boiler controller, but the controller is not capable of meeting the sequence the engineer came up with. When I call their tech support and tell them what im trying to do, they tell me not to do it.