Network Meltdown (Flashing Switches!!!)

Hi All,

Lately I've been having big issues with my Cbus Network.

The switches throughout the house will randomly flash, then sometimes they will not turn on and if they are on they won't turn off. If you play with the button or wait a while they will eventually co-operate.

This is the old cbus system (Big black box relays, cream power supplies, white switches)

We also have a PC connect module which according to it's instructions, if it's flashing there is lack of power. So we called out the sparky and they put in a new power supply but did not try find the supposedly broken one, as the new one will overcome it somewhere along the line.

Yet the switches are still playing up! What could be causing it now?

All I can think of is:

1) One of the three existing power supplies is busted and creating havoc, so find it and unplug the bugger (The new one will then take over)

2) I read something about system clocks - Since the PC connect was purchased after the original installation what used to/still does create this 'clock'? - Theres only powersupplies, relays and switches throughout the place.

3) Last resort, a switch has created havoc or a wire is shorting or something.

What I intend to do tomorrow is remove the link between the two halves of the house (each end as a power supply) - So if either end flashes I can eliminate half the house as the cause...correct?) - Or does it need this system clock to work? (I don't know whats generating it!!!)

OR Go unplugging power supplies one by one and see if that fixes it.

Thoughts? Suggestions would be appreciated!!!

 

The three holy grails of cbus troubleshooting (well, according to my experience anyway)

Burden
Clock
Power Supply

If one of those is gone, then you're in trouble.

From the description it sounds like the network is underpowered.
Do you know if you have a hardware burden attached (rj45 plug with red heat shrink)?
If not then you may have a software burden, which like the clock can turn themselves off on occasion.

Do you have the cbus v2 or toolkit? If so you can set the unit address of one of your dimmers or relays to 001.
Once you save that off you can then apply a clock and burden to the system (in the global tab). You may need to hit apply twice to get it to save (old bug).

If you are happy your clock and burden are set, and its still flashing I would say its power related.

Use the software to check what voltage you are getting back on the line, anything below about 26 volts and you will have trouble.


I wouldn't think separating the two halves of the house will help as you may lose the connection to the burden/clock. If this does fix it however it may indicate a network fault which could be anything from a damaged cable to a telephone accidentally plugged into the cbus network (seen it happen several times).

Michael

 

Hmm well if it's become underpowered it would be because of a power supply has gone because it's worked fine for 6 years....

Strange the new power supply hasn't compensated unless the new PSU needs to be down the other end of the house lol as the distance won't cut it. It's a very long house....

If a relay is already 001 should that have a clock already on it?

Can i find if a clock is set somewhere else? (As in will two clocks mess everything up?)

 

"Do you know if you have a hardware burden attached (rj45 plug with red heat shrink)?"

The only thing I can think of on the network with an Rj45 plug is the PC Connect...As it's old systems you have to manually wire it (Pain in the ass!!!)

 

If the network has been working fine for 6 years, and now is suddenly giving trouble, then something has changed. The challenge is to work out what exactly has changed.

Given the components you describe, the first candidate is those old cream power supplies. Occasionally when they fail, or prior to complete failure, they can start injecting garbage onto the C-Bus network, which wreaks havoc with communication. Since you have a new power supply (5500PS?) installed and connected, I would disconnect each cream power supply in turn from the C-Bus network (physically remove the wires) and re-test your network.

C-Bus power supplies all share the load of powering the C-Bus network, so just adding a new one won't necessarily solve a problem unless one of the others has turned itself into a brick.

Regarding clocks, lots of C-Bus units can have their clock generator feature turned on but only one unit will actually be generating the clock at any given time. If the original clock generator fails, one of the other units will take over. It's recommended to have 3 or so units on the network with the clock active.

Many C-Bus networks require what is called a network burden which, in very simple terms, gives the devices on the network a load, so that their communication circuitry has something to make it do a bit of work and generate nice clean signals. If your PC interface is in a cream box, the burden will be set by a jumper that is under the cover. If your PC interface is in a DIN rail enclosure and has either a teal or purple cover, the burden will be set by software.

Indicators on a PC Interface flash for a few reasons. The Unit-Comms indicator flashes whenever the unit is sending/receiving data from a PC. The C-Bus indicator will flash at about 4Hz if the network voltage is between 15V and 20V. It will go off if the network voltage is below 15V or if no clock signal is present on the network. If it's flashing erratically then that suggests that either the network power is unstable or the unit is having trouble getting a lock on the network clock signal, which could be due to a lack of network burden or noise being injected into the network.

It is also possible that one of your white switches has become faulty and is affecting the network, although this is rare in equipment manufactured anywhere in the last 10 years or so, but still a possibility.

 

"DIN rail enclosure and has either a teal or purple cover,"

The PC connect is one of them with the purple cover. I'm going to go disconnect one of the old PSU's from the network and wait 24 hours see if anything changes. If not, try the next one and so forth.

 

Using C-gate, How can I check what has clock/burden enabled other then manually going through them all?

I've found the clock to be enabled on the PC Interface but can't find the burden to be enabled anywhere...What does the burden do exactly and is it needed?

 

I assume you mean using cbus v2 or toolkit rather than cgate?

If its a dimmer or a relay, only the device with unit address 001 can have the burden turned on, if its in the pc interface it will be in the Global tab, it should be below the enable clock checkbox.

As stated above the burden allows the comms to balance out. Technically there are installs that theoretically do not require a burden (this is from Clipsal), however I have yet to come across one that did not benefit from having it turned on.

Software ones can run fine for years and then get switched off, I always use a hardware one. If this was the case however you would have a difficult time scanning the network or loading units.

So it still looks like a power issue.


Michael

 

ah yes toolkit. whoops.

Well nothing is addressed as 001 at the moment. Starts at 002.

Hmm well I'll keep trial and error with the power supplies and go from there.

 

If the 5500PC PC Interface has a purple cover it can act as the network burden at any unit address. You can check if this is active in any unit by loading the Toolkit UI for that unit and checking the Status tab.

 

Yep it's unchecked. Should I tick it?

 

Update:

CBUS Got stuck at 7:45pm tonight.

No more flashing LED's though which is rare except none of the switches worked for about 10 mins then it fixed its self.

What would have caused that?

Also I don't think the network has a burden because address 001 is a switch and I'm almost sure there is not a physical one...Does CBUS work without a burden?

EDIT: the B/W touch screen was also showing - Connection to cbus network lost.

 

The answer to this question is... maybe.

It depends on a few factors, such as the number of units, the length of cable, the number of power supplies, etc. The easiest thing to do is scan the network using the Toolkit software, transfer the programming to the database, select the network node and look at the information in the window. You'll need to add the power supplies to the database manually, as Toolkit can't see these units on the network. If the network requires a burden Toolkit will say something like '1 burden required'. Most sites usually have 1 network burden enabled.

If you understand what it does. It's quite likely that the network will continue to work with this turned on, even if there is already a hardware burden located elsewhere in the network.

Without knowing the specifics of the site, working through all the changes you have made and the things you have tried, possibly visiting the site itself, no-one could make an accurate assessment as to what actually happened.

Still keen to hear how you go with the power supplies. With those old cream box units, if the unit is faulty sometimes they'll come good after a power cycle, but eventually they will start misbehaving again, so keep an eye on it.

 

had flashing switches but I had a network burden a clock, thing was someone didn't seal the roof and water got in, and this caused it to flash then work normal then flash again at random intervals. Just a suggestion besides the normal diagnostics. Maybe someone went through the roof and crushed the cable?

 

We dont think the cables been cut or anything. It just seems to be one of the units.

But now that we have taken off one of the power supplies we haven't had flashing lights since!

 

simo122,
having had this problem on about 6 sites now, all around the 10 year old mark, the problem was down to faulty switches. All of the 16 switches i had to repace so far on these sites were 8 x 2 gang and 3 x 4 gang 2000 series switches & 5 x 4 gang (key input modules - slightly different size special order) out of stainless steel plate setups. To find the problem i sugest you start looking at switches that have been previously flashing and at switches either side electrically on the bus of those switches. It is time consuming excercise as these faults appear at different random times and rarely whilst i was on site. Powering down the c-bus network normally quick fixes the problems sometimes for a couple of days or for only about 10 mins on a couple of sites. I actually showed the custormers which breakers to turn on and off to reset the system when problems struck and i wasn't near to help them out.
I was told a "you didn't hear it from me" un-official explanation of of why these switches went faulty by a now defunct ex rep, but everybody else plays the "I havent heard of that before" company line/excuse. I sent some of these fauly switches to one of the now ex managers who didn't want to know and promply sent them straight back to me with a note saying they were out of warranty, nothing further would gained looking into this matter.
I have also turned off the "restore to previous levels" in all old key input switches on all old installations to help fix this problem.

 

<Start Southern USA drawl> Being an old timer around these parts <End Southern USA drawl> I can shed a little light on the subject.

There are two very different situations being experienced as written in this thread and I have experienced them first hand several times.
First when old cream power supplies (5100PS) start to turn up their toes they can still be providing DC power to the bus however their filtering circuits can fail resulting with filling the bus with noise. The tricky thing in both situations is these faults can be very intermittent. Now in the middle of all this back around the same time key input units had a firmware that would see the LED's flash if C-Bus comms was down for them. In the case of old faulty PS they would usually bring the whole bus down. If you are presented with this sort of scenario introduce new power supplie(s) so you can isolate original units until the fault clears.

The second situation is where an individual or several key input units stop communicating. Importantly if there are other units nearby including output units still working properly then you can assume the fault is in the key input units. In many cases for these old old units there is a capacitor that fails (somewhere in the capacitor count around number 7) Based on the resultant fault I believe this capacitor decouples the C-Bus communications off the bus (this has not been confirmed by NASA or any other reputible scientific body - merely my own guess). This fault can also be very intermittent up until the time when the cap fails all together.

Now before anyone starts going off about faulty equipment, replacement costs yada yada, we are talking about gear that is now over a decade old. In the case of the key input units I believe vibration from units / buttons being pressed (in my house bashed) over the years must contribute. Dig up a ten year old mobile phone or TV and wonder whether you expect to get another 10 years of faithful service.
In the second case and probably the first it is capacitor failure, and capacitors just fail over time. My air conditioning system has big arse electrolytic capacitors for start and run, I replace these every few years, I even have a spare for my fan coil unit ready for it to go next.

PS. I would not be recommending to any client to drop circuit breakers to clear faults. It might get things going, but will only delay the obvious. Probably better to diagnose the faulty devices and change them out...
So if the whole network fails you are probably looking for power supplies. If one two or more key inputs only fail then change the key input units. Key input faults will not normally cause problems for other units where old power supply faults certainly will.
Leaky roofs, crushed cables etc just add to the fun and mental exercise of which path to run down first... ;-)
Hope this helps.

 

Just to let you know, CBUS has failed yet again.

Nothing is turning on, flashing again.

Time to try taking out another PSU and putting the other one back in.

 

I had one problem like this and it was a bad RJ45 socket ( with a lead plugged in )on a L5508RVFP unit that coursed the C-Bus intimately stop working.
Touching the cable was effecting the system.
Hope this helps.