cause of communication error

Hello,

C-Bus network of my customer became unstable condition suddenly.

History
Install of C-Bus network at February 2012.
8ch Dimmer x 3, 12ch Relay x 2 and switches sensors x 24

August 2012 first failure
Customer informed me that lights suddenly go out. Saturn switch LED was flashing.
The fault disappeared in a few hours.

December 2012 second failure
Symptom of failure is the same of first failure.
But Saturn switches is not flashing.
Network error was displayed only once in Toolkit.
Some of units were not finished synchronization in Toolkit in network scan phase.
The units of synchronization error are not always the same.
C-Bus Communication Error screen is displayed in the Spectrum touch panel sometimes.

Without error in the 5100NA Network Analyzer.
All units of voltage over 29V.
All C-Bus units appear in ToolKit window and all units can be configurable.
Network changes from the initial installation, add the unit has not been carried out.

Communication Error will not disappear even if i disconnect some of the switches and sensors.
Communication Error does not appear when i made small network which has only PC I / F and Dimmers and Relays.

Please give me advice how to determine faulty unit(s).
Please tell me about how to identify the cause.

Thank you very much.

 

Have you tried adding or removing burdens?

 

Hi Darren,
Thank you very much for your comment.
I added a software burden.
When i connected 5100NA Network Analyzer and pressed Network Burden button, Remove Burden LED was trended ON.

I have two C-Bus installations work now.
I don't want to spend a lot of time to fix this trouble.
Any suggestion is helpful for me.
If you can give me steps of clearing C-Bus Network Error, It is very helpful for me.

Thank you very much.

 

Hi Yoshi
I would try installing a physical network burden. (the red heat-shrinked item on a RJ45 plug)
Your attached screen shots are too small to read so can't see what you've done there, but you have to have the unit that the burden is enabled in as Unit Address 000 and then save the enable burden twice to make it work (from memory).
Personally I have found the "network analyser" quite useless.

 

Unit Address 001 I think

 

Matthew and Dave,

Thank you very much for your comment.

This is update for my customer's trouble.

At first, I checked software burden and clock in address zero unit.
Last week, I cleared check software burden in address zero unit.
And i added hardware burden in network.
A few days after customer informed me that trouble occurred again.
This is a situation of trouble.

Suddenly all lights were off.
After that customer tried to lights on in Spectrum, It was succeeded.
Spectrum showed Network Error message some time in error condition.
NEO switch LED blinked in error condition.
Display of Spectrum was blinking slowly in error condition.
Error condition started about 5PM.
Error condition was cleared about 7PM.
I requested customer to turn OFF and ON for AC power of C-Bus units.
But trouble did not clear.

I guess this trouble is depending on low voltage of C-Bus network.
I arranged four With Power DIN units in network.
Total C-Bus power source is 800mA.
The C-Bus network needs 503mA in my calculation.
It is enough for making stable C-Bus network.

I added 350mA C-Bus Power Unit for tentative solution.

If AC line voltage for C-Bus units is reduced by some reason, Also C-Bus power will be reduced.

I have a plan to arrange Voltage Data Logger for AC line and C-Bus line.
EL-USB-3 is DC 0-30V range Voltage USB Data Logger.
Maximum range 30V is not enough for C-Bus line voltage.
But it is Cheap.

Please give me comment.
How do you think my guess?
Can i connect DC Voltage Logger in C-Bus line?

My customer is president of big Construction company in Japan.
I need to fix this trouble as soon as possible.
Any suggestion and comment is helpful for me.

Thank you very much.

 

If it is possible to split the network into two or more independent parts - each with sufficient power supply, hardware burden (or enabled software burden) and with enabled clock, you might be able to isolate the cause.
If you can split the network in half, the customer may not even notice for day-to-day functionality, but you then have a chance to narrow down the area where the fault may reside.
I have found in the past that an intermittent connection or an intermittent fault within a unit can produce symptoms similar to what you are finding. You may have burden and voltage correct, but if there is an intermittent connection (or intermittent unit), you can have this problem. If any units are mounted in areas where water damage or physical movement is possible, I would try and isolate them first if possible.

 

Hello Don,

Thank you very much for your comment.

Yes, I have some parts (C-Bus Power, C-Bus Bridge and Dimmers) then I can make split network.
If i make split network, customer may not feel a failure as you say.
And I can not get notification from the customer regarding C-Bus error.
I will visit customer in this week and try to add voltage logger and making split network.

Any suggestion for next action for resolving the problem, It is very helpful for me.

Thank you very much.

 

Hi!

This cbus behaviour is familiar to me.
I got sudden lights off, Saturn flashes, etc as you have. You can search through the forum for "Saturn flash" made by me.
I checked everything from scratch and the last thing I found that fluctuations in AC main made "reset" of relay with power supply and burden on board. I discovered that when the main's current slightly "drops" the relay's C-bus LED turns off for several seconds and then recovers to normal. This in turn summons low voltage drops and burden unsync - that's why Saturn flashes.
So I decided to connect all mains of all power supplies to online UPS.
From that time - works stable - no flashes, no lights off.
Also hardware burden is a good idea.
Good luck

 

This is an update for customer's C-Bus trouble.

I got a call from customer at 26th Dec regarding C-Bus trouble.
I visited customer's house. But trouble was already gone.

I arranged additional 350mA C-Bus power and C-Bus Diagnostic Utility PC at edge of C-Bus network.
Attached a physical connection of C-Bus units at customer's house.
DIN units are connected to AC1 which is connected to Emergency Battery System.
The Emergency Battery System is not a UPS. It will be a power source at Earthquake emergency condition.
I guess it gives wrong AC power at C-Bus trouble condition.
So, I arranged additional 350mA C-Bus power and C-Bus Diagnostic Utility.

I got a call again at 31th Dec regarding C-Bus trouble.
I visited customer's house. But also trouble was already gone.

I got a logging data from Diagnostic Utility.
And i found wrong data in trouble condition.

2012/12/31 11:02:38 0:00:12 Source Unit 245 Time Clocks: Request Refresh
2012/12/31 11:06:35 0:00:08 Source Unit 245 Time Clocks: Request Refresh
2012/12/31 11:16:57 0:00:28 Source Unit 121 Time LENGTH ERROR
2012/12/31 11:18:31 0:00:01 Source Unit 245 Time Clocks: Request Refresh
2012/12/31 11:32:54 0:00:03 Source Unit 245 Time Clocks: Request Refresh
2012/12/31 11:32:54 0:00:00 Source Unit 245 Time Clocks: Request Refresh
2012/12/31 11:36:11 0:00:05 Source Unit 121 Time Clocks: Unknown LENGTH ERROR

Spectrum sent "Time Clocks Request Refresh" and
WISER sent "LENGTH ERROR" of Time Clock command.
Spectrum sent wrong data command which has non registered group number in ToolKit.

I think "Time Clock Request Refresh" was sent at starting Spectrum unit.
Time Clock command is long data so it was not distributed in Network Condition.

Please give me comment for my information.

Thank you very much.

 

My advice is that you should try to log the measurement of AC main power that drives all C-Bus Power Supplies when the error occurs and be sure that Cbus PS's have proper AC voltage all the time.
The best condition is if all the Cbus units are connected to the same AC phase.
I believe that most of uncovered in cbus manual problems come from main current.
Also you can try to recreate the problem manually - with turning off the AC power of CBus PS's one-by-one and inspecting of cbus behavior every time.
Good luck

 

Hello

I got a lot of advice.
I say thank you here.

My trouble was resolved.

Solar power unit is connected to AC line at customer's house.
It has inverter unit for making AC.
It is pseudo sine wave.

I think it gave noise on C-Bus network.

I arranged UPS which has function as AC wave correction.

Network trouble was gone.

I appreciate all of your advice.

 

Happy to help!