carrier ccn comm problems

[hvt]

Hello all, I have an ivu with 40 or so 33zcvavtrm, three carrier rooftops 48EKs, ccn controllers built in (not sure what model the controllers are) I currently have no comm whatsoever, all devices show offline on the i-vu. I connected my NST, run a bus scan and nothing shows up when I run bus monitor I get the same error over and over again (cant remember what it is right now)

It seems to me that the network wiring is not in a daisy chain, it comes in and out of the third floor control panel several times so I am able to look at the network in segments with my NST, I can see several of my third floor controllers (not all).
I ran out of time today to check the other floors, I was hoping somone here could help me out with this, why no communication at all?
one bad device maybe?

I should mention that there are two repeaters in the network one per floor. there are no lights on the repeaters.

thanks in advance!!

[okfrommyhouse]

hvt,

Could be a bunch of stuff, you need to start with service tool - if you can't see the bus with that sure won't with ivu. Two things, are the repeators black fid modules, B&B rs485 cards, or carrier modules that look like a 6400?

No lights is the place to start, got power? leds on the above show different things depending on the component. If it looks like a carrier 6400, probably a 38.4 bridge which creates a sub bus off the middle phoneix connector. If so, once you get lights on, have to play with bus # and baud rate in nst see. You can check by unhooking a controller off the bus, go to search utility and set the address to 0,0 and enable the check all bauds. Thats a place to start.

[hvt]

I was back at the building today, I checked the network segments I mentioned, found all but 8 controllers, of those, 4 were powered off I put the network wiring back the way I found it, still no comm.
the repeaters are carrier CAES420876-02 they have two power inputs at the top and two CCN connectors on the side. the lights occasionally flash but look weak, they are powered by two plug in 20vac transformers, I verified 20 vac at the repeaters.
I looked at all of the controllers that did not show up on network scan i can connect directly to them no problem, checked the wiring between devices didnt find any problems (yet)
Should I be able to see the repeaters as network devices?

I did not try checking all bauds as you mentioned OK, not quite sure what you mean

the installer has connected the bus wire at all devices together with a wire from the zone sensor? does this sound right?

I am kinda stumped here, this sytem has been online for a long time and sudddenly there is no comm at all, which is why I started looking for a wire that had been cut somewhere, even if it is cut somewhere I should be able to see something on the network

[okfrommyhouse]

HVT,
Think you meant a CEAS.. not a CAES.. thats the really old FID style of repeator. All the FID modules I've worked on have a battery to maintain the program if theres an extended power outage, supposed to change annually.

I've never used these repeators so not sure if that applies here, there's a lot of knowledgable ccn guys like Balibe on this forum, maybe they could shed more light on that. I would think if you plug directly into a controller with nst you should be able to see it.

[hvt]

Thanks OK, it sure would be nice if one of the ccn guys notice this post!!

I have not been back to site since last post, I am hoping to finish up this week

Thanks in advance!!!

[lowdrive]

I am not an experton CCN, but I have one job with the original web product. What I have seen is the comm failure on the network. You mentioned the dim or non-flashing lights. When I encountered that problem, it was traced to a controller that was taking the communication down.

I pulled apart sections of the network until I had removed the problem. At that point, the lights began blinking strong again. I found the controller that was causing the problem. The first couple of times, resetting power to that controller would clear the problem. Eventually, even that failed, but by that time, we had received a replacement controller.

[hvt]

Thanks lowdrive, I have isolated a problem area of my network, I have not found the problem yet though.
It is encouraging to hear that one device can bring down a network!!

[lowdrive]

The Carrier controllers I was working on, had the plug for the comm. termination, which I expect all Carrier controllers use. They were very easy to unplug for testing. It would be nice to have someone watching the lights/frontend as another person pulls terminal plugs from the suspect units.

If the problem is in the wiring itself, you would, of course, need to physically break the wiring apart. The first question I ask when comm wiring starts acting up all of a sudden, "Has anyone been working in the ceilings?"

One interesting item I encountered on one of my Carrier comm adventures, was the mechanical room controller resetting upon the intermittent comm signal. It was turning the CHW pump on and off every few minutes. Of course, the chiller would then trip out on loss of flow, and there was no more cooling. I had to hotwire the pump starter to keep it operating during the comm problems. Luckily, it was warm weather so the pump would be on fulltime anyway.

[Ausccn]

HVT,

Plug into 1 device only (disconnect it from the network) and see if U get comms.. what s/ware R U Using?? S/T or C/View?? if using S/Tool do a Bus scan....it is only RS485 comms and the CCN network uses voltages around the 3 volt +/- so (depending on what device) if U dont have these 4 starters then something is wrong.

The CEAS420876-02 is just another 232 to 485 converter so if U can prove that it works on 1 module then at least U know your comms is Ok.

If this is the case then you have something else pulling the network down which could be anything from just 1 controller that has a problem or maybe multiple address's on the 1 comms trunk/bus......a lot of CCN devices drop back to address Bus 0 Device 1 when S##t happens.

Try the above out and if that doesn't work email me in my profile..

Aus..

[hvt]

thanks ausccn ill be back shortly!!