Dixell xweb 500 no link problem

[ronaldo9]

Happy Christmas everyone,

I have an Xweb 500 controller monitoring a supermarket with the usual cold rooms, freezer rooms, display fridges and freezers, it has been behaving itself since it was put in over a year ago,of course it waited till Christmas to start acting up. It started with random "no link" alarms on some cabinets , the alarm would last for 5 mins or so and then everything would return to normal, this was happening every few hours or so, pretty much all cabinets have alarmed in this way so far, Now one of the serve over counters has gone crazy, showing exceptions for everything, high value pb1 same for probe 2 basically every alarm that it can throw up, I won't be able to get into the shop till Wednesday and the first thing I'll do is replace that serve over controller, wondering has anyone come across this intermittent no link alarm, it's strange , I actually set up the system so I know it pretty well but can't figure out why it would drop communication and then come back, thanks for any help

[padraic]

i could write a book about that problem... your network is going down to earth and going slow.. not the controller id say... have you door switches or emergcy stop buttons on your coldrooms

[ronaldo9]

Only one freezer room has a door switch,,why.?

[padraic]

the door switches have 2 contacts one for lights and the other for switching controller when door open probaly thats the set up im guessing..
but we had ice freezing the switches and causing a very small voltage down the network and earthing the network aswell and all our problems were down to the door switches and it was just in the freezer rooms and no a bother in the chill rooms...
the door switches contacts in the controller and the network are linked inside the coldroom controller so if theres and problem with door swithes your in trouble..

disconnect the switch at the controller and see how it goes

[goshen]

Hi
we had a smilar problem,as padraic described.
you should try his advice.
good luck

[al]

Also the screen can be connected to the digital input which may help "earth" it, have you spoken to Graham in frigotech yet?

al

[padraic]

i also had alot of dealings with graham over our few problems and he was very helpfull

[ronaldo9]

Thanks guys, padraic thanks for your advice, I'm a bit worried that you said you could write a book which suggests there is a world of problems , I'll check out the door switch and get back to you,, thanks al I think I remember graham saying something about the screen not actually been an earth as such, my memory isn't great on it but I'll give him a buzz I think I still have his num somewhere. He definitely knows his stuff on Dixell .

[al]

It's not an earth, just helped against these problems, use external door switches where you can as well, less trouble. Check no one has stabbed in an extra controller rather than looping it in.

al

[ronaldo9]

Hey guys,

No luck with the door contacts, still no link alarm coming up, was on to Graham , he seemed to think it was interference from power , I'm not sure, nothing has changed or being moved in the last year, being chasing cables all day, any other ideas.

[al]

i've had sites where this pops up after time, maybe someone has run high voltage cables on your tray, can you disconnect parts of the circuit each day to narrow it down? Or would it make a difference to complete the loop to the XWeb like a ring main?

Al

[goshen]

Hi
we found that connecting the screen on the shielded cable only on one side helps to elimenate many problems
you describe
best regards

[padraic]

feck it was hoping that would get you out of trouble..

as goshen said there about the screen.. we had one site where the screen was connected to the earth and it caused alot of trouble..! slowed the network down and got no link alarms.. your cable might be pinched somewhere and earthing the screen

[al]

Or another thought, if a controller is mis wired with the comms cable mistakenly put in with a live switch you would get intermittant problems as the switch makes/breaks, easy to do on the older controllers.

al

[ronaldo9]

Thanks guys and happy new year,

I sorted out the problem, I disconnected 3 other door contacts, they were for chill rooms . At the same time I replaced some cables on a couple of display cabinets. Not sure yet which sorted out the problem I'm going to reconnect the door contacts next week so I'll know then if they were causing the problem, I was getting caught up thinking that the network had been working fine for a year and nothing had changed electrically , I guess these problems just pop there little ****ing heads up just to test my patience, I don't have the patience to be a fridgee,,,,thanks all for the help

[stufus]

Try being a footballer so;)
Still with the same company??
Happy New Year by the way.
Cheers
Stu

[padraic]

was thinking it was the door switches allright... glad you got it going..

pity the door switches dont have there own circuit and have no link to the network

[WoodyP]

Hi
Looks like you sorted this out. Just as a general observation that might be useful, quite often when you get these network problems it can be electrical noise getting onto the network and it can be really difficult to pin down the cause (I once had a problem which turned out to be an industrial compactor three doors away !)
Something always worth trying is to use a spare core in the network cable if you have one (not the screen). Most Dixell controllers will have two digital inputs that share a common terminal. Use this core to connect up to all these common terminals then terminate it back at the XWEB by connecting it to the RS485 terminal marked Gnd (ground).
This is not earthing but what it does is prevent the noise from concentrating it's effect on any one controller by spreading it accross the entire network thus diluting it's effect. It doesn't always work but it's suprising how often it does cure the problem.

[naotaka hirano]

Hi.
I have installed xweb500D already 3times.
It's my exeperience. May be your issue is wrong wiring.Dixell controller Rs485 terminal are dipend on difference.
some products are left terminal +.some products are right terminal +. Please confirm it.
And if +and - wiring are touch also indicate no link.
I am looking forward to your sucsess.
from japan.