Desigo Insight

[Infralapfs04]

Greetings everyone!!

I'm new over here, so, sorry to be bothering you for a first time! :o

Has anyone ever faced this problem with Desigo:

- Cannot acknowledge alarms in the screens nor in the alarm viewer.

- Cannot change no setpoints.

- Cannot change no schedules.

- In the other and, even with all this buggers, we are receiving operating states and other analog values...


Apparentely it's not a communication problem, as the router is working properly.

Anyone who faced something similar, please give us a hand! :)

Thanks!!!

[picnik]

OK, couple of questions,

What subsystem do you have: PX, NCRE, Nitel, Visonik?
Do you get time and date stamps in the alarm viewer?
What access level do you have in Desigo Insight (check in configuration utility if you have it)?
Can you change setpoints in object viewer?
If you have PX, have you tried a PXM20 (or the PC based emulator)?

I'll assume PX. It seems to me your access level in Desigo Insight is not high enough.
What is likely is either you are logging in as a basic user, or the person who programmed the PX forgot to set the access levels correctly on the objects.

Are you the customer or the tech working on installing the system?

[Infralapfs04]

OK, couple of questions,

What subsystem do you have: PX, NCRE, Nitel, Visonik?
Do you get time and date stamps in the alarm viewer?
What access level do you have in Desigo Insight (check in configuration utility if you have it)?
Can you change setpoints in object viewer?
If you have PX, have you tried a PXM20 (or the PC based emulator)?

I'll assume PX. It seems to me your access level in Desigo Insight is not high enough.
What is likely is either you are logging in as a basic user, or the person who programmed the PX forgot to set the access levels correctly on the objects.

Are you the customer or the tech working on installing the system?


The system is a PX.
I'm working with Engineering level access, as we have programmed the system. The access levels are correctly assigned, the system has been functioning correctly for about 9 months 'til now, and this has only began to occur last week.
Last week, just after I posted in the forum, I made a project check, recompile and restart, and the system was running great. Today it just went back to how it was before.
We've checked all stations, bus, etc.. everything seems to be ok.
We're having this many doubts and questions, because it's something that never happened to us before, and resolutions from SBT are being a little vague.


Oh! And by the way, we have an integration of S7-200 in the system. With this integration we have a lot of software (Citect) generated data points, hour counters, etc.. can this points fill any buffer, and crash Citect??

Thanks!
Cumps!

[picnik]

What is your IOserver configuration? I'll assume that you have configured this differently from "normal" in order to integrate the S7-200 directly into Desigo. I'm no expert on the IOServer as Siemens tend to try and keep this bit secret (that or they don't really know themselves :p) but this is where my gut instinct says the error might lie. Try a pack of the citect project that holds the IOServer/s

If this doesn't work look to see if there is an error log created. Mine is stored in:

C:\Documents and Settings\All Users\Application Data\Siemens\DESIGO\INSIGHT 3.0\Temporary Files

There's actually 2 files there called englog.trc and errlog.trc so do a search if they're not in the directory above.

Opened it using the trcui.exe program in the bin directory of insight. This should point you towards where the problem is. They can get quite large (mines 45Mb) but if you want clean it out, let a few errors appear and email it over (emails in my profile) I'll see if I can help identify the problem.

Let me/us know if you find a solution :)

[ec26500]

I am new in Building Automation by siemens desigo Insight and i want that all our Package A/C units will be OFF and ON on a given schedule. I opened the Time Scheduler application but i cannot find the device that i want to make. Could anyone help me to add the device to the time scheduler application. the I/O module is 2Q250

[picnik]

You probably need the original XWorks software. There might be a way to add the point as a named reference in the scheduler but the XWorks is the proper route if you want to change software.

[ec26500]

i cannot find any Xworks in my automation station. is there any other way to make the command in a time scheduled switching. Thanks u very much for the help i appreciate it very much.

[picnik]

Can you describe your setup in more detail?

From what I understand you have a PXC64 (or 128) which has a rail of IO modules, one of which is a 2Q250. (note the 2Q250 is actually a 2 digital outputs module)

Has any software been written so far for this controller. Has the 2Q250 you want to switch on and off been created in the software already and if so what is its point name. Also what is supposed to be switching it at the moment?

If the output has not been created in the software already then you will need the XWorks software to create the output. If you don't have the XWorks software you will need a Siemens engineer or systems house to do this work for you.

If you would prefer to post pictures of what you have rather than describe it feel free to either post them here or my email is in my profile and you can send them direct

[ec26500]

hi mr piknik im once again needing your help, can you gave me sample on how to make statement in reaction processor because all my entry dont work maybe my program is not correct, i want that the control module (2q250) of our package units will follow the status of the control modules (2q250) of our lighting . Also since the time scheduling of this AC unit is not possible , can u also teach me how to make the reaction processor become a time scheduler.

thank u very much for your help. i have nothing here which will guide me

[picnik]

I'll give it a go, but without knowing your system its going to be a bit general.



Create a new reaction. Fill in the first tab as necessary.

On the second Tab "Condition", click the add button. Here select the point that you want to act as the trigger (your lighting point?) and the state that will activate the reaction (On).

On the third tab "Action", click the add button. Action type will be write then select the point/points you want to command (packaged unit output).

you will then need a new reaction to switch it off, so follow the procedure above but the condition will be when the point goes off, and the action will be to write an off to the packaged unit output.


Another way to do it would be to use the desigo connect. Far easier than reaction processor.

The other way to do it would be with a bit of cicode. There is a file called project.ci and when copied into the top graphics project runs. In there you could write a bit of code that looks at the state of the lighting point and if different from the packaged unit point, command the packaged unit point to be the same as the lighting point. add a sleep statements so its not running all the time and its a quick and easy way to command points from other points.


To do it as a time schedule, you could on the condition tab choose time trigger. Set the date range to a few years or more and select the time you want the condition to be true (7 a.m?) and select the days you want it to happen. Action tab would remain the same. again you would need a second reaction to switch it off at night.

Of course, all this would depend on the PC always being on but I recon you understand that. Have you not got anyone in Saudi who could do this by programming. Its a far better solution. If you need a name I could probably speak to someone about getting the name of someone good over there.

[ec26500]

thank you mr piknik , we did already talked to the one who made our building automation but unfortunately they dont reply or they have a problem so dont worry to contact another person.
I will try what u just said. thank you very much

[ec26500]

mr picnic i tried to make a reaction entry but not working, there is pop up saying that found no server . how can i activate a server? thank u

[picnik]

could be you have no licence for the reaction processor.

Check in licence utility (licutil.exe) and check that you have an entry for reaction processor in the licence file. It doesn't come as standard so may well not have been included. Its not that cheap either so not usually included unless asked for.

If its not not included try looking at Desigo Connect instead, its an extra bit to install when desigo is put on, but can be added later by running the install program again. This can be used to link points

[ec26500]

mr picnic could u see this one, this is info on our desigo . i want to know how much it cost to activate a reaction processor . thank you very much for your help

[picnik]

To check your license details, run the LicUtil.exe file in the insight\Bin directory somewhere under program files.

Should look like the attached picture on the right hand pane


As for prices, you'll have to see your Siemens rep about the cost, as firstly we can't give prices on this forum, and secondly I haven't a clue :angel: (particulary as your based in Saudi)

[ec26500]

mr picnic do u have a website on desigo insight so that i can learn more advance? my problem before in time scheduler was solve by installing a 24 hour timer in the equipment instead but someday i will try again on programming side.. thank u very much , i think i like to be inclined in Controls.

[NohaWagdi]

Hello Everyone,
@ Infralapfs04:
as for the alarms aknowledgement Problem, i faced it once, and i tried to enter the bacnet reference number for the management station instead of entering the management station name in the fiel of--> global-->NotifClxx-->{0}-->Reciepent-->B= [enter the bacnet refernce of the MS here instead of the management station name that can be obtained from configuration utility} this problem occured because both site and management station names were typically the same while both have same bacnet TD so i used the bacnet refernce number instead of the name.
hope i made it clear.

i also wanna ask about how to generate automatic reports using the reaction processor. i need detailed steps. can anybody help? i have desigo insight V4.1

[ashareef24]

Mr. Picnik


I am facing problem in pxc64u using xworks software. i cannot configure the project since the service led of com1 is blinking continuously. I tried download the compatible firmware but all in vain. Can u please help me regarding this issue......

[picnik]

Its probably knackered!! ;)

Is this BACNet over LON or BACNet over UDP/IP??

I'll assume LON and that you've done a node setup and you have the correct end of line resistor on the comms terminals. These are the first things you need to check.

if its BACNet over UDP/IP, is the card in the correct slot and firmly seated (has to be pressed down very hard)

When you do a firmware download does it download correctly?

[ashareef24]

Thank you for your good response indeed.

It is BACNet over LON . I already made sure of the correct end of line resistor on the comms terminals. If there was a problem of correct end of line resistor, the reading of the controller would not appear in node setup being unconfigured rather it would'nt show any controller.
Yes the firmware has been downloaded correctly.

I am also facing some typical problem in using Desigo Insight Software v4. It was running fine with no problem. All of a sudden , one message started appearing since 2 days. I tried to solve but all in vain. Whenever i open the desigo insight software, the message appears " Exception from HRESULT: 0x80044002. Starting DI Server failed . Please check $ErrLog traces for details".
I tried to restore the system in previous date. It restores the system perfectly but same message appears upon starting the software.
I really appreciate ur good reply.

[picnik]

With regard the PXC64U, without a resistor (RXZ01.1 or RXZ02.1) it is possible for the node setup to read the device as unconfigured and then when trying to configure it fails on the setting of the BACNet part. Check the terminator is on CLA and CLB.

Is it just the node setup that fails? The fact you can download new firmware suggests the controller is OK. There is some commands that can be used in the firmware tool to do some resets but I don't think this would be required if the firmware download works OK.

What LON interface are you using. have you used it on any other controllers recently? Is it a PCMCIA card? make sure its set up as NSIPCC in the Lonworks plug and play applet in control panel.


As for the Desigo Insight, the error you are getting is the same sort I get if my database upgrade process hasn't work properly when upgrading from previous versions of project.

First thing I would try is to go to project utility, right click the project, select "Upgrade" and then "to DI V4 project".

Run through this procedure and see if it works then (including graphics upgrade).

If not then create a new project and see if that works OK. This will tell you if the problem lies with your project or your DI installation. If the new project is OK the you can always transfer over the graphics and database in just a few minutes (or maybe a little longer if a complicated project) to the new project.

[zlotvor]

Hi,

What firmware you use on PXC64? In the firmware description you will find different led blink patterns described - it's a good start for troubleshooting.
Are you sure the termination resistor is ok? Sometimes it's possible to make node setup with wrong LON termination, but impossible to download after that.

What version of xworks you have? There is a new version (v4.10.030) with various bug fixes and new features. And it's same for DI (4.1 BL10). Install all patches from install DVD, you should get it from your local Siemens rep.

[ashareef24]

HI everyone ,

Thankyou very much for your co-operation.

I am using PCMCIA card. I have used the terminator resitor RXZ02.1. Working in XWORK V4. I studied the data sheet of Pxc64-u , it clearly shows that if the service led of the controller COM1 blinks continuosly , that means LONWORKS chip is defective. The controller was working well since 2 months but all of a sudden i am facing this critical problem. Can anyone tell me the reason what could be the reason of LONWORKS chip being defective? What is the solution for that?

[ashareef24]

Friends,

Can Someone help me regarding Desigo Insight Problem. The situation at the site is that I am using PXC00U controllers , Thermostat QAX34.1 and RXL22.1 to monitor the status of individual room temperature in BMS Central Station. Room individual Cards are there to operate the lights and Thermostat of the rooms which we monitor in BMS Station.

The question is that whenever guest remove the card before leaving the room in order to turn off the light and airconditong, it gives us alarm in BMS station. Infact it should not give us alram rather it should give us room unoccupied. There might be some settings in Insight to set this issue.....?

[zlotvor]

Ashareef,
Sorry to hear that, is it covered with warranty? If not, you can try to solder new Lon transmitter from other faulty equipment (big black brick near LON connector).
I seen that fault only once, and I have couple hundred PX's behind me. Maybe I'm just lucky.

For DI - what alarms you get? Just occupancy or the complete controller? Describe little bit more how did you create KNX datapoints prom RXL?
Check EnAlm and RefVal values. If its not alarm point then EnAlm should be No, and for alarming use Disturbance pin (if needed)

br, Z

[ashareef24]

dear zlotvor and all friends,

Thank you very much for your prompt reply. The Pxc64u controller is out of warranty. Also i do not have spare PXC64u to replace the new Lon transmitter. Anyhow i will try to manage it. I thing Fluctuation of the electricity might be the cause of LONWORKS chip being defective.

Regarding the desigo insight, i found the solution of the problem since there was no DI points in the controller RXL were used, thats why it is obvious that it would not give me occupied\unoccupied status of the guest.
Actually i have manually configured the parameters of QAX34.2 to run the fcu and see the status in BMS station through PXCOOU controller.
Right now i am facing the problem that the thermostat QAX34.2 of all the guest rooms are turning off themselves after nearly half an hour without any reason. I thing there might be some parameter to fix this issue?

[zlotvor]

dear zlotvor and all friends,

Thank you very much for your prompt reply. The Pxc64u controller is out of warranty. Also i do not have spare PXC64u to replace the new Lon transmitter. Anyhow i will try to manage it. I thing Fluctuation of the electricity might be the cause of LONWORKS chip being defective.
It's not compulsory to dig it from the same controller, it can be any LON capable controller with FTT10 transceiver inside (the big black brick). We almost always use UPS power supply for the controller, it helps!


Regarding the desigo insight, i found the solution of the problem since there was no DI points in the controller RXL were used, thats why it is obvious that it would not give me occupied\unoccupied status of the guest.

Did you follow the procedure:
ETS > PX-KNX > XWP > DI ?



Actually i have manually configured the parameters of QAX34.2 to run the fcu and see the status in BMS station through PXCOOU controller.
Does it mean that you actually see the status changing?


Right now i am facing the problem that the thermostat QAX34.2 of all the guest rooms are turning off themselves after nearly half an hour without any reason. I thing there might be some parameter to fix this issue?
It's the room controller configuration! The QAX34.2 is just a simple HMI that takes input from user and displays information. Check the controller config.

[picnik]

Not sure what field device your using, but I had the same problem when using RXL's via PXC00-U. Turns out I set it up as a 3 speed fan instead of single speed. Also check the behaviour when the setpoint is satisfied. If set as a room control the fan may be set to switch off during the deadband.

[ashareef24]

Dear All friends especially Mr.Picnic. ( URGENT )

I am using PXC22.D Siemens Controller using XWORKs V4.1. Software. The problem which i faced was that when i make node setup. it is made but as soon as i try to download the program it shows PX Cannot be found on the network. While i am sure of my network cable and end resistance since with the same connection i downloaded the program in another DDC's.

I tried to download the firmware V4.1, The firmware loader loaded successfully while on downloading the basefirmware for pxc22.d it is giving me "zmodem error". it is written Base firmware information not found.
Also it is written Base Firmware: No alternation.
Firmware Loader: o.k.
Now the fault led of pxc22.d is blinking continuously . As per datasheet it says that if fault led blinks continuously, it means Missing \ Corrupt Firmware.
Now I want the solution please.

[ashareef24]

Dear All
I am finding strange problem with pxc22.d. When i give it 24V ac the run status does not appear whileddc appears in node setup . When i configure it , it is configured but a pop-up appears which says that BACnet Device Configuration Failed.
The service led is blinking continuously . From datasheet it says that it means that no IP address configured.
Now i cannot download the program since it gives no node setup even the node setup is done (but with error bacnet configuration failed). Also i cannot download any firmware since it says that no base firmware availabe.
Can anyone help me ?

[picnik]

Seems an interesting problem.

The only thing I ever had close to this was when I needed to do some work on a PXC00-U doing RXL's. I tried downloading the firmware but it wouldn't take the download and said base firmware not available. Of course without the base firmware I couldn't download the software using XWorks.

I was pulling my hair out as this was a Saturday and of course the good people of Siemens dont usually work weekends. On the Sunday I had to do a Modbus integration and I had the same problem! Two PXC00-U's with the same problem?

This was the error message I got:

http://i395.photobucket.com/albums/pp31/Picnik_01/Work/errormessage.png

As it turned out, someone suggested I try a different USB-232 converter. Sure enough the dowload worked! seems the USB-232 converter could read info coming in so the it looked like the firmware download tool was sort of working but in actual fact it wasn't as it couldn't send data.

Oh how I wish I had a laptop with a built in 232 port :whistle:

Hope this helps

[ashareef24]

Dear Picnik

I am really glad to see you prompt reply . That depicts your co-operative nature and i really appreciate it.
Well i need to clarify that u mean you were using the USB-232 converter it did not work but when you try different USB-232 Converter (same type)it worked. Do you mean that?
If Yes, that means that i would purchase another USB-232 Converter to fix the bug.
For your knowledge, i already tried to download firmware through USB-232 Converter, Also through serial port of the laptop, Problem still persist. Please Reply soon.

Also Regarding my question BaCnet Configuration failed for PXC22.D i am still waiting for reply.....

Once Again thanks for your reply..

[picnik]

Looks like your controller might be faulty. There are some commands that can be used on the controller while using the firmware download tool if its in "Coma" mode but I don't have the documentation to hand to work out what this is. Press the ? key when you've connected via 232 and you should get some hyperterminal type messages up that you might be able to follow.

Have a word with your Siemens Rep and see if you can get your hands on the new firmware download tool thats due to be released (unless you have it ready!) It looks pretty good and a lot more professional...

If your firmware is faulty there's no way you can download the software from XWorks or do a node setup.

[ashareef24]

Dear Picnik and Zlotvor ( need your response as well)
Thanks for your response . I had two different problems with two pxc22.d controllers. One of which is solved i.e: the firmware connector which i was using was not tightened well since its screws are lost. That's why it was giving me error zmode etc.. Also the firmware tool was having some problem i used different one . This solved my problem

Now,
Regarding other controller, as i mentioned before When i give it 24V ac the run status does not appear while ddc appears in node setup . When i configure it , it is configured but a pop-up appears which says that BACnet Device Configuration Failed.


Also fault led does not blink when i try to download the firmware by pressing firmware key with reset button. I tried to make a jumper between some of the insulations inside ddc with a wire during this test i found that run led glowed for a time i was keeping the wire jumpered. Now i dont know which method should i use to fix this problem. since no firmware can be downloaded because fault led does not blink at all.
I hope i have clearly explained to you the situation.
Please find the answer for me.....?

[picnik]

Can you confirm that the correct buttons are being pressed

http://www.big-eu.org/catalog/siemens/023_PXC..D_CM1N9215en_08.pdf

Have a look on page 7.

Also check that the AA battery is healthy and that the bit of plastic is fully removed that stops the battery discharging while not powered.

Try holding down the firmware button, powering off and on the controller and wait 15 seconds before releasing the firmware button. (The reset button just does a short power off. Maybe this is faulty)

I must admit I'm a bit concerned your shorting things out in the controller with a bit of wire. There's 24V floating round in there as well as lower voltages that power chips and stuff. Easily blow stuff up if your not very careful.

[ashareef24]

Dear Picnik,
Once Again really thankful for your valuable suggestions. Actually i did what you suggested me.But even then i cannot download the firmware since the status led (fault) fails to glow after pressing firmware button 15 minutes with power off and on and hence no firmware can be downloaded.
I doubt if the ddc was defective, it wouldn't show the service led blinking meaning that no ip is configured only. Any how,
How can i get the details of chip board inside pxc22.d controller to evaluate further?
Also , can you tell me how to become the member for this site, since my status always appears Regular Guest instead of member .
Hope to get reply from you soon.

[picnik]

What firmware did you download to it? is it V4 or downgraded to V2.37?

did you use PXC_CMP12-22 V2.20.424.dwz or PXC_CMP12-22 V2.20.420.dwz if downgraded?

[ashareef24]

Dear Picnik<
I tried to download both firmwares which i have for V2.37 PXC_CMP_PPC12-22 V2.20.420.dwz AND V4.1 FIRMWARE PXC_CMP_PPC12-22 V2.20.420.dwz.
But still problem is not solved. I dont have any other firmwares which you mentioned.

I thing the problem might be the hardware defect . Still the controller does not respond the status led (fault) after pressing the firmware button? If the problem still persist do you advice me to order new ddc or still their is some hope?

[ashareef24]

Dear picnik,

Sorry, the firmware version 4.1 which i have PXC_CMP_PPC12-22 V4.00.080.dwz.

i have mistakenly wrote same firmware versions in my previous email.

Please Reply....

[picnik]

The reason I asked what firmware version for 2.37 was I heard that new PXC's were coming out with new chips in them that were not compatible with the 420 firmware.

I received a bulletin last February "recommending" I use the 424 firmware but I recently heard that using the 420 with controllers with the new processors could damage them and brick them.

You should speak to whoever sold you the controller to find out the full story as I only got it word of mouth, nothing official. I'm not even sure what the symptoms are and whether it can be fixed.

[ashareef24]

Dear Picnik,

I am facing problem in two siemens Vfd's (SED2-15/32X) which i configured year before.They seems to be hanged i.e: whenever i press the hand or auto button to start, it gives me message on the display (P----).
I made it facotry reset and again configured the parameters i.e: voltage, current,power facotor,rpm of the motor, kw of the motor (15 kw that is same as that of vfd), power factor,ramp-up time, ramp- down time. Still the problem persists i.e: the message (P----) appear.
I removed the wires coming from the motor, the problem still persists. Please guide me how to solve this issue. Thanks.

[picnik]

Sed2's are not my specialty. I'd recommend you start a new thread on the forum and ask the other guys on here

[ashareef24]

Dear Friends,

I am facing problem in two siemens Vfd's (SED2-15/32X) which i configured year before.They seems to be hanged i.e: whenever i press the hand or auto button to start, it gives me message on the display (P----).
I made it facotry reset and again configured the parameters i.e: voltage, current,power facotor,rpm of the motor, kw of the motor (15 kw that is same as that of vfd), power factor,ramp-up time, ramp- down time. Still the problem persists i.e: the message (P----) appear.
I removed the wires coming from the motor, the problem still persists. Please guide me how to solve this issue. Thanks.

[ashareef24]

Dear Picnik,

I am using XWORKS V4.1. Whenever i connect to the project through Node Setup into the xowrks network configurator, it connects without any problem.
But whenever i try to download the project, it runs during downloading it stops and gives me error as follows
Compile Chart as block type (244:4064)
The online CPU does not respond . Please check the connection (Set PG\PC Interface, Rack, Slot,...)
I have tried another LON CARD with another cable, even then the same error is coming.
I tried to download in another project still the same problem persists.
Sometimes it says error as follows;
The automation station could not be connected online.
Please give me the solution for this query.
Thanks in advance .

[picnik]

The error looks familiar but can't think what it definatly is. Was the project upgraded from a 2.37 project. I sometimes find the upgrade process is not always perfect and old version blocks are left in.

[ashareef24]

Dear Picnik,

I need the answer for this plz.
Actually the scenario is that i have 3 ddc's connected with each other in star connection i.e: from the two ddc @ roof of Hotel the cat 5 cable is coming directly to the router PXG-80N with terminal resistor RXZ02.1L.F (105 ohms), while one connection coming from the basement ddc to the router.The distance between the roof and basement ddc's (PXC100.D) is no longer 300 meters, while the router is fixed in the basement ddc. I cannot see the 3 ddc in xworks rather when i connect the above two ddc's direct to the router, i can see both of them , but whenever i add the wires network connection from the basment ddc to the router, basement ddc does not appear but sometimes the above 2 ddc's @ roof disappears as well.
Can u tell me the reason why?

[picnik]

You really need an RXZ01.1 if using a star topology. Try this first. If you want to use RXZ02.1's you need one at each end of the network. I'm sure you can make a bus topology network the way you describe the layout of your network.

The distances don't seem too excessive so also check if there's any interference from inverters or similar devices that cause a lot of electronic noise.

[ashareef24]

Dear Picnik,

Thanks for your reply. I put RXZ01.1 resitance in the router side , it worked. Now i can see all the 3 ddc's. But now problem arises that for sometime i can see all the 3 networks, gradually one of the ddc's disappears fr sometimes then re-appears itself. This will disturb the readings in desigo insight. As per your previous reply
"The distances don't seem too excessive so also check if there's any interference from inverters or similar devices that cause a lot of electronic noise"
I need to know how to check the interference from inverters or similar devices keeping in view that i only have 3 ddc's in the network?
Also, i checked the bus topology using RXZ02.1 on both ends of the network but all in vain.

Waiting for your reply....

[picnik]

To check for interference you will need something like an oscilloscope or a protocol analyzer. I must admit I'm no expert on this so maybe read some of the other threads on this site. (Do a search for LON interference as it is LON cabling being used)

I still think that your best bet is to wire it as a bus topology and use an RXZ02.1 at each end as this gives a far more robust network, but if this didn't work for you then I'm a bit stumped. Make sure all your termaninations on your network are properly made as a bad one could cause problems.

[zlotvor]

Dear Picnik,

I need the answer for this plz.
Actually the scenario is that i have 3 ddc's connected with each other in star connection i.e: from the two ddc @ roof of Hotel the cat 5 cable is coming directly to the router PXG-80N with terminal resistor RXZ02.1L.F (105 ohms), while one connection coming from the basement ddc to the router.The distance between the roof and basement ddc's (PXC100.D) is no longer 300 meters, while the router is fixed in the basement ddc. I cannot see the 3 ddc in xworks rather when i connect the above two ddc's direct to the router, i can see both of them , but whenever i add the wires network connection from the basment ddc to the router, basement ddc does not appear but sometimes the above 2 ddc's @ roof disappears as well.
Can u tell me the reason why?

Hi, and sorry I didn't responded earlier.

Generally, we NEVER allow star configuration in our networks because many times it showed that star is much worse solution than a line. Even if line is longer than allowed if there is not to much interference, the network will work ok, but in star configuration 300m is always the max. length you can use.
The behavior you described is exactly the symptom of broken communication caused by star configuration. Reconfigure it to line and put two RXZ2.1 on two most distant ends of the cable. That should be ok then.
Many times i've seen improper connection of cat.5 cable. Actually, they connect one twisted pair as one wire and another twisted pair as second wire. This is improper way of connection, you should use only one twisted pair for LON.