L5508RVF freezing up and disabling entire network

Wanted to check if anyone else has had this issue and what may be causing it.

I have a commercial install that consists of 2 networks connected with a network bridge. One of the networks consists of 5 relays (3 x 12ch, 1 x 8ch, 1 x 4 ch) which are installed in 5 seperate DB's. There are 2 legs of cbus cable connecting these relays, one leg connects 2 of DB's/Relays and the other leg connects 3 of the DB's/Relays. Both Legs come back to the B side of the network bridge.

The network on the A side of the network bridge contains the 5500NAC that runs the schedules,scenes and trigger groups that control all the relays on the B network. There is also a touch screen user interface avaliable for manual control.

This install has been working fine for a few months until in the last 2 weeks on two occasions the L5508RVF on the B network has been "freezing up". All 8 channels will suddenly turn ON and stay on (i am only using 4 channels of the relay the other 4 don't even have group adresses programmed) and the whole netwok will freeze up aswell. The cbus light will go off on all relays and the b side of the network bridge and I cannot scan the network in toolkit. The A network is unaffected and continues to operately normally. I can only get the L5508RVF responding again and the network "unfrozen" by power cycling the L5508RVF.

Obviously since the network is frozen up it does not respond to commands from the the 5500NAC so i get phone calls from the client reporting that all the outside lights are on in the middle of the day (should be turned off by the PE-cell at sunrise) and all inside lights are staying on all night (should be getting turned of when security system is armed at closing time).

A couple of side notes:
- None of the relays on network B are directly switching loads, they are just switching 240v contactors that are handing the loads. So definatle not exceeding the 10A rating of the channels.
- the L5508RVF in question is only recieving 6 on/off commands per day (unless someone is sending manual commands through the touch screen) so its not exactly being overloaded with excess commands on the network.
- the L5508RVF is sitting in a DB that is outside of the building on the north side with almost no shade, so it it would be exposed to direct sunlight for most of the day so I am wondering if it is an overheating issue. There are 2 other switch boards on the north side of the building but they would get a bit more shade and the relays contained in those DB's do not have power supplies.

Anyway long story short i have removed the L5508RVF and have set it up at home to see if i can replicate the fault but so far its working fine. But i am thinking since it could be a heat issue i am not going being able to replicate the fault unless i can replicate the same environment.

Has anyone elses experienced the same or similar issues with a relay? I did find the following thread which has similar symptoms: https://www.cbusforums.com/threads/l5512rvf-all-channels-turn-on.7351/

 

Have u checked the reported cbus voltage of this unit?

Do u have a network bridge u can chuck it behind to allow u to monitor it while protecting the other units from its misbehaving?

 

Reported cbus voltage was in the low 30V range, can't remember the exact number but i do remember checking it and it was in the low 30's for all the relays on that network.

unfortnately i don't have a spare network bridge, would be a good idea though if i did have one.

I have asked the client to monitor the lighting activity and to contact me if the issue happens again. Will leave it for a week or so and fingers crossed it dosn't happen again which will reinforce that the L5508RVF is possibly faulty.

 

This sounds like a classic cable fault. All channels of the relay turning on could be caused by a faulty "remote on" connection. Cbus lights going off means that the clock signal is missing. Check for bad connections, water/dirt ingress etc. It is rare (but not unknown) for a single unit failure to take out the whole network, but a cable fault certainly will.

 

Something that came to me overnight was client plugging in an RJ45 network cable into a cbus port.

I got lucky when my wife did it once and no damage (but all lights went off).

 

I've had a fault on a new relay with a built in power supply so that when this particular relay was plugged into the C-Bus network I could only see the Serial interface when scanning the C-Bus network, immediately it was unplugged I could scan the whole network again. On talking to other point0ne installers they brought up that this is a major concern that they have come across. It is at a point where we wont put in a output module with built in power supply. The original power supplies interfered with the C-Bus network so they got changed out to DIN Mount power supplies and then we had a batch of those that would go faulty in a very short time. I believe it's the power supply that's the problem in your relay.

 

So is this a new and current problem or a historical issue

 

Hey Lliam, what did you find?
I think it sounds like a hardware intermittent fault, not a programming issue.
& I agree with Ashley, sounds most likey a cable fault, maybe something moving when it gets hot / heat related?.
I had a relay doing the same but only when someone was working in the DB, turned out to be the swarf from drilling the top plate had amassed in a L5512RVF, so sometimes when it was bumped it must have shorted something (the all on contacts?) all the channels pulsed on & then off again.

 

Just an update on this for anyone interested (late i know)

After removing the 8ch relay and leaving it for around 2 weeks with no relay installed in that particular DB (rest of cbus network remained unchanged though) there were no further issues reported by the client.

I then managed to get hold of a used 4 chan relay (with psu) so i returned to site and installed and programmed it as a temp replacement. I also reterminated all the rj45 crimps on that leg of the network back to the network bridge, i had already tested each section of cbus cable with a network cable tester and all sections passed but i decided no harm in redoing the crimps.

So far no reports of faults or issues from the client and its been a few weeks since i installed the temp 4 chan.