Terminating resistors needed on Cbus network?

Hi All,

I've been forced (again) to ask a stupidly simple question by circumstances my installer (who obviously doesn't know what he is doing) has gotten us into and am prepared to take the flames as long as I can get an answer today.

As per my last thread (cbus network wiring), the installer has now connected three legs of the cbus network in parallel with each other and connected to the cbus system. He is trying to scan the network and detect all the units but its not working unless he does a scan of each separate leg and even then hes not getting all the units. What he hasn't done is put a burden / terminating resistor (5500BUR) on the end of each leg, is it definitely necessary on the cbus network to terminate each branch of a network? I am thinking it is the problem but would like to hear other's opinions or 100% confirmation that it is the problem before taking a course of action as we have limited time to finish the installation (I am waiting on this network scan so that I can do the programming!).

Cheers!

Craig

PS...sorry to those before in the other thread that were only trying to help me, I am doubly frustrated having to run around finding this basic fundamental sh$t out at the last moment when it should have been covered by the PM and electricians before the job even started!..I would greatly appreciate your help again

 

No, it doesn't need to be terminated at the end of each leg.

The whole network should probably only have 1 "burden" going by the diagram you posted previously, this can be either a hardware one (5500BUR)or enabling the software seletable one on one of your modules. If you are using the physical one then check and make sure that the software burden is turned off on all modules through the c-bus toolkit. Personally i prefer not to use the physical one.

Someone else will be able to tell you the exact way to identify number of burdens required for a network/best practise for how they should be configured wth hardware/software so i'm just going from my own experience on this one.

Hope this helps.

Cheers

Al

 

Thanks Al,

Just called him about it, turns out he had neither the hardware burden in or the software one enabled...got him to enable the software one in the PC interface module and see how that goes.

He seems to be getting limited success doing one leg at a time but not all together (pre burden enabled), he has a theory (god help us, we really need someone that knows what they are doing at this point, not theories but its what we've got to work with ) that if he can't get it to work with all the legs in parallel then he will wire it so that the network loops back through the same cat5 cable using 2 unused wires within the cable...don't know if that makes sense or is possible but he's basically experimenting until he gets it all to work :S

Cheers!

Craig

PS...so I think something like this...(network 1 and 2 are the legs, not separate cbus networks )

 

Sounds more like a power issue then a burden problem.

Too much cable, or too many devices on each leg dragging the network down.

Check your voltages.

 

Yeah they are physically far apart, there are 32 devices all up...originally there were 6 and another 26 have been added, he is currently able now to successfully scan 27 of them but as soon as he adds the other "leg" on with the final 5 devices it crashes the network...so I'm assuming a bridge is required?

I have gotten him to enable the software burden in the pc interface module through which he has been test scanning each leg, the hardware burden isn't being used.

Cheers!

Craig

 

There's a relay with its own power supply at the start of each leg, there are no standalone power supplies as such just one PC module, 2 input modules, 2 output modules and a HMI, the new 26 units are 25 x 4 pole change over relay units (5504RVFC) and 1 x 4 button plate switch (B5034NL). All 25 relay units are connected to 240v as such to provide power for the changeover and the first on each leg is supposedly one that provides a boost to the network. That's the way he explained it to me anyway.

I am waiting for them to test the bus voltage which I thought would have been the first thing they would do when suspecting a bus voltage drop issue.

Cheers!

Craig

 

According to the PM, there are 22 x L5504RVFCP and 3 x L5504RVFC. (going on what he has said to me, I assume he believes the 3 RVFCs are the ones that boost the signal/power...to me going by the model numbers I think its the wrong way round if that's even what they are supposed to do? I am thinking a bridge (5500NB) is in order?)

In regards to the cbus clock, currently only the pc module has it enabled...I just restored a backup of the project with 21 of the 25 relay modules scanned and all of them have the clock disabled.

He's got some other ideas on how to get it to work tomorrow, if your able to give me a solution before he "tries" them that would be awesome

Cheers!

Craig

 

C-Bus installation

CBM Craig,

Do yourself a favour and contact one of the Appproved Installers or pointOne members straight away!!!!

You can find them listed on the CIS website

It appears you are here in Melbourne. There are a number of very professional, competent companies who can help.

It is very obvious your sparky has no idea.

This will undoubtedly lead to a poor installation, poor functionality, poor reliability, and ultimately a poor experience for you and your family.

Unfortunately, many electricians who attend a three day training course profess to be EXPERTS. I have spent many years helping contractors out of the sh*t with C-Bus.
Having said that, there are a number of very good sparkies who are very competent.

You will have to live with the technology for many years, give yourself a chance to enjoy the experience.

 

Thanks Darren and Ashleigh,

Its not actually for my house or any house, and I can't divulge details on the actual project...plus I'm not in Melbourne, I am in Victoria but the project is in Melbourne

There is a PM (project manager) running the whole show and doing a lot of the work himself along with the electricians...but he obviously doesn't really know what he's doing I've tried to hint at him to call Tech Support and then maybe they will say to get an approved installer out there but Im not in a position to outright tell him what to do Because I had some experience working with the cbus system that runs the lighting in my office I was contacted by this PM from our other office to do the programming work and now for some reason he contacts me on every problem he comes across including the wiring which I have ZERO experience with but am slowly learning the fundamentals through this whole situation

Current status is he has now been able to detect the 4 button plate switch after doing something funky with the wiring (im pretty sure he hasn't tried to loop back through the same cable yet though) so all that remains are 4 of the 4 pole changeover relay modules to detect.

Im kinda at my wits end with the whole thing, being the 3rd link in the problem solving chain when he should just bloody call tech support or get someone qualified out there.

Cheers for everyone's help

Craig