TCP communication fails

I have a VI that communicates to six devices simultaneously over Ethernet. Three of these devices are on a serial port server so the PC recognizes them as serial ports and I use Visa Serial for this communication. The other connection is to a PLC. The problem is with the two watlow controllers connected via ethernet. After a couple hours of continuous run, the information from the Watlows gets garbled or fails completely while my other devices communicate just fine. If I stop and restart Labview the communications come back properly.
The program opens three TCP connections each to a different IP Address. then goes into two while loops. One while loop is faster and talks with the PLC. The other while loop is slower and talking to the Watlows. I use the same remote ports for all three and asked the customer to change them to be 502, 503, 504 but this caused an immediate loss of communications.
Anybody have any ideas? These are Watlow EZ-Zone controllers.
Attachments:
SIP Main Interface Beta IV.vi ‏535 KB

Hi Technics,
Did you try to use the Process Monitor from Microsoft to see why the communication hangs up ? There are many more programs that can be helpful, if you search for "procman" or "procmon. with those programs you can monitor the system and see waht goes wrong. also if your program uses NI-VISA. you can use NI spy to monitor the system.
Thanks and have a great day.

Similar Messages

How to combine TCP communication VI to other Labview VI

Hi,
I am doing a project that is a sport timing system. In my timing system, I am trying to communicate with another computer by using TCP/IP while the timing system is running.
I am trying to combine it into a VI, I have tried to solve it by convert one of the VI to sub VI, but it doesn't work or 1 computer cannot run TCP VI and my Timing System at the same time.
Can any one know how to solve this problem ?
Attachments:
3switch 3-2-2012.vi ‏14 KB
timing system A 24-2-2012.vi ‏48 KB
timing system b 1-3-2012.vi ‏29 KB

Hi,
timing system b is a sport timing system that like a stopwatch with 24 three-input switch( 0s,2s or 50s will added to the total time if turn on 1 of them).
TCP communicator active and passive are the other 2 VI. I want to combine TCP communicator actives VI and timing system b' VI into a VI (that run in computer A).
And the TCP communicator passive is run in another computer( computer B).
about the stop button in timing system b's VI, the Vi can't function when I add a stop button in it, but it run normally once I removed the stop button. The timing system b is based on the NI tutorial or examples. I based on the example to design the stop watch function.
Please help me how to solve it.
Thanks
Attachments:
timing system b 1-3-2012.vi ‏29 KB
a TCP Communicator - Passive.vi ‏33 KB
a TCP communicator Active 1-3-2012.vi ‏31 KB

Error 63 in executable TCP communication VI

Hi guys,
I'm having some trouble with 'simple' TCP communication between two LabVIEW executables.
It works fine if both VIs are on the same machine (localhost or 127.0.0.1, the computer with the development system), but if I compile and then run them I get error 63 ('Network connection was refused...') for the VI that contains 'TCP open connection'.
I have read the forums and a number of NI KB articles, but I'm still not sure what properties and options I have to set. There doesn't seem to be a good how to guide.
To keep things simple, I have built two example VIs that ship with LabVIEW 8.6 into executables: 'TCP Communicator - Active.vi' and 'TCP Communicator - Passive.vi' (C:\Program Files\National Instruments\LabVIEW 8.6\examples\comm\TCP.llb). Only modification: I have increased the timeout for 'TCP listen' from 10 to 25 seconds, to make the executable easier to use on slower machines.
The example programs should work like an instant messaging system:
- Start the 'passive' VI, this VI starts a TCP listener service on the specified port and network address.
- Start the 'active' VI next, this VI tries to connect to the 'passive' VI over TCP.
- When the connection is established, you can send and receive text messages
That's how it should work and, as long as both VIs run in the development system, it does.
In executable form however, it does not.
I have a suspicion I need to add a number of entries to the ini file to allow access from everyone, not just 127.0.0.1
Other troubleshooting suggestions I have read:
- setting the 'Svr.TCPAccess' property at run-time
- modifying 'Tools > Options > VI Server: Configuration'
Can anybody give me some pointers on where to start debugging? For your convenience I have attached the executables and their ini files.
Thanks in advance for your help.
Paul
Attachments:
NI-TCP-comms.zip ‏593 KB

Hi Akiel,
Thank you for your reply. I did some more experimenting, here's what I did:
I started the 'active' VI and immediately got error 63, whether or not the 'passive' VI was running (on the local machine).
I pressed 'continue' in the error dialog and execution of the program stopped.
I copied the 'passive' VI to another computer, turned of the Windows (7) Firewall and then ran it.
I then changed the machine field of the 'active' program from 'localhost' to 192.168.1.17 (the address of the remote computer).
I restarted the 'passive' program (because of error 56, time out)
I restarted the 'active' program
This time both programs behave as expected.
Repeated the above experiment with the firewall turned back on, with both programs on the same machine.
This time it does work without modifications
Looks like Windows Firewall is probably to blame here, it's behaviour is unpredictable when it comes to whether or not it blocks connections.
Now for the big challenge: getting the Windows 2008 R2 firewall to cooperate with LabVIEW.
I'll update this post when I have more information.
Paul

TCP Communication - How can I remove the priority of which VI will run first?

Hi. I would appreciate for any advise.
I want to communicate (send data) to another PC using wireless radio. I am presently testing the shipped examples;
TCP Communicator Active.vi and TCP Communicator Passive.vi. I will run first the Passive.vi in the other pc (as
indicated in the instruction) and then Active.vi on this pc.
I want to remove or neglect the priority of which VI will run at first (either of the VI can run first).
If in the case either one of the PC is not transmitting data, it will just trigger a LED or any kind of indicator.
Can anyone helped me to do this? or is there any other example vi that will do it?
Thanks a lot.

Hi Mr Christian,
i decided to use TCP/IP for peer to peer communication. I made an example VI of what i am doing but i cant make it right especially on the "Time out error". I would appreciate for any advise.
Kindly see the attached VI's. The Crane 1 will be the Master or Server and Crane 2 and 3 are Slaves or Clients. Slaves VI will pass their data to Master while Master will distribute the data to each VI.
As a rule, i have to run the Master or Server first and Slaves will follow.
But as soon as i do this i am getting this Time Out error hence data are not being passed. I tried changing the values of time out constant but not lucky so far. I know that if i can fix this time out error, all the VI can communicate properly. I should see three moving cranes on each VI.
Additional question; If all of the VI are running, and I intentionally Stop for instance Crane 3 (Slave), then it will show an error (LED) that Crane 3 data is not available. So far i can do this.
But for instance I will run again Crane 3 (Slave), is there a way to RESET the connection programatically so that Master VI will once again accept the Crane 3 VI?
Any advise I would greatly appreciate.
Thanks a lot.
Attachments:
Crane 1 (Master).vi ‏40 KB
Crane 2(Slave).vi ‏35 KB
Crane 3 (Slave).vi ‏35 KB

TCP communication

Hi everyone
I would like to use TCP communication to send temperature sensor data and data from my USB camera to another client pc. I have tried using remote panels with limited success because of the bandwidth requirements for the camera. Using the VI attached can someone help me on how I can use TCP communication in this application. An illustration (or reference) would be greatly appreciated .
Solved!
Go to Solution.
Attachments:
nstflux01-1.vi ‏113 KB

sent wrote:
Ok, so here is my shot at what you guys are talking about. The sever and client see each other just fine but I cannot read any of the data. I think that my problem is that I don't know how to read the scan correctly. Can someone show how to do that ?
Do you know that format of your messages? Are they terminated with a specific character or pattern? A common way for messages to be sent via TCP is to have some type of message header which identifies the message type and generally provides the message length. If you data follows such a protocol you will need to get the specifics of the header. You would then read the header which will let you know how much more data you will need to read. The most basic header is simply the number of data bytes that follow. So the message would consist of a number (generally 4 bytes) followed by the number of bytes for the value of number.
If you don't have a message header of any type another way that you can read variable length data (but it is not fool proof) is to read a single character. This is where you would have your overall timeout for receiving a message. If you don't receive a message in the designated amount of time you can perform what ever error handling you need. Once you a read a single character you then begin reading chunks of data (perhaps 1024 bytes at a time) and use a very short timeout. When a timeout occurs on this read that would be an indication that there is no more data. This type of approach only works when you have some time between your messages.
The last alternative is if you have some type of message termination character or pattern. In this case you would read data until you see the termination character or pattern.
Mark Yedinak
"Does anyone know where the love of God goes when the waves turn the minutes to hours?"
Wreck of the Edmund Fitzgerald - Gordon Lightfoot

Monitor TCP communication.

I want to monitor TCP communication from my client to the server.
I am using google web service,and using my client i am sending the request and receiving the response.i want to monitor those communications.
Any one have any code.
Thanx

You can try using jpcap

TCP Communication Problem - not passing data???

Hello.
I am working on TCP communication. I need to pass data from one PC to another and vise versa. I started with the shipped example TCP Communicator Active and Passive VI. Using the shipped example only with the Wireless Unit connected to both PC i am able to communicate and pass data between each PC.
Now, placing the shipped example VI to my Main VI (separate while loop), I am NOT able to make it run properly. What happens is even if i move the control data on one PC it does not update to the other PC.
I am attaching the example VI and I would appreciate for any advise.
Thank you very much.
regards,
jtc
Attachments:
TCP Communicator Active.vi ‏51 KB
TCP Communicator Passive.vi ‏53 KB

Hi jtc,
"if you need to share data aquiired rapidly, a work-around is to accumulate the acquired data and send larger "bundles" less frequently" - do you have a simple example VI for this?
No! - though we could develop something - but a solution for the current example, might not be helpful to your final program. For instance, we would capture & accumulate a "batch" of data "produced" by individual user actions, then send the "batch" of data to the other machine and what? Perform all the updates to the GUI in rapid succession (what's the point?.) Show the last user action/setting?
It might be a good time to develop the architecture for the Master and Slave applications.
This sounds like an interesting application! Do you mind sharing some detail? For instance, are the slaves generating data? Are there a fixed number of slaves? Is it necessary to mirror the Master's data on all the connected slaves?
Like Johnny-5 said: "Input, I need Input!"
Cheers!
Message Edited by tbd on 10-17-2008 08:29 PM
"Inside every large program is a small program struggling to get out." (attributed to Tony Hoare)

NI VBAI TCP Communication With Staubli CS8 Controller

I have a Staubli CS8 controller running the VAL3 programming language. Their documentation is light but I managed to brute force the solution to controlling DIO (Digital Input/Output) commands. I am having trouble brute forcing the SIO (Serial Input/Output) commands. The Staubli appears to only be capable of being the TCP/IP communication Master. I have my laptop's IP address configured in the Staubli controller with the ethernet socket name of "test". With the NI VBAI TCP/IP communication manager set up as slave and the TCP server enabled, the Staubli controller claims it is actively communicating with the NI VBAI socket server, and status is OK. In the VAL3 programming language I believe I have correctly linked the sioLink(siotest,io:test) between the variable name and the actual hardware device port. I try to send serial text strings from the CS8 to the VBAI. But I cannot figure out where to observe the serial communication traffic in VBAI. I have it set up right now to run infinitely and check the TCP port for serial input, but don't see any results. Anyone integrate these two systems yet? I have been using both for quite some time so I'll catch on fast if someone can run me through some quick steps if they have done this before with NI and Staubli. Thanks.

Actually the VBAI side of the communication was easy and straighforward. Plenty of help files and info on the NI support site. The Staubli side was more complex with minimal information supplied in the programming manual, and I was having trouble with that. After experimenting further I was able to transfer data between VBAI and the CS8 controller. If anyone else ever tries this here is what you need to on the Staubli side of the communication:
Set up the ethernet socket on the teach pendant:
Create a new socket and call it VBAI (or anything you really want)
Set the Staubli up as the TCP communication SERVER
Set the termination character for " ; " which is Staubli ASCII character 59 (default is ASCII character 13 which I could not generate in VBAI)
Create the Staubli program (VAL3 language ONLY):
Create a new program in your application
You need to create a serial input output variable (In the data sheet add a new SIO variable, call it sioASCII or whatever you want)
Also create a string variable (In data sheet add a new STRING variable, call it sTEXT or whatever)
Now you must link this variable to the actual hardware socket
Then read the socket and output the value to the teach pendant display screen like this:
UserPage ()
CLS ()
sioLink ( sioASCII , io:VBAI)
sTEXT = sioASCII
putLn ( sTEXT )
Run your VB Inspection on infinite loop first, then run the Staubli program and the inspection data will be displayed on the CS8 teachpendant. Yeah, it always looks to easy after you figure it out the hard way.

Technology blocks TCP communication?

My doubt is: How is the transmission of packets? For Socket?
Someone there knows answer me?
Ps: I am Brazilian I'm using google translator
Tanks

Hi Camilo,
Your question is How LAbVIEW Transfer TCP packets? Is by socket?
In the following link you can see what socket service LabVIEW uses to TCP Communications
http://digital.ni.com/public.nsf/allkb/07E11647E145A62A86256B19006DCD1D?OpenDocument
Regards,
Abel Souza
Engenheiro de Aplicações
National Instruments Brasil

TCP communication and Remote Panel programming

Hi all:
I am developing a LabVIEW program which is to used remotely. I am planning on using Remote Panel Access or TCP Communication for my application. I would like to know why is a better choice and what are the factors I should consider in choosing one of these. Jsut for information, I am also using serial communication in this program using RS232 cable.
Thanks in advance,

I am not sure what the legal aspects are for the Run Time Engine. You will have to dig deeper or contact NI if it will not let you load it. From what I read is:
Additionally, the Run-Time Engine allows your browser to display VIs that are embedded in Web pages. There are two downloads that are available. You only need to install one of them. LVRunTimeEng.exe is a smaller download intended when viewing Remote Front Panels in Web pages. It does not contain the full run-time engine, but will allow some executables to run..............
http://digital.ni.com/softlib.nsf/websearch/1F1EBEA6D03A67E6862570A400531F97?opendocument&node=13205...
Yes, you can have an executable and that would be the preferred method. Start small and work up to the final version. Start by using your developer version and have it generate the WEB page. Using the same computer you can view the page and take control using Microsoft Internet Express. From there build it into an application, try it again. When all looks good then put it on the server. You are limited by licenses on how many WEB pages you can have running.
Hope this helps,
Matt
Message Edited by mfitzsimons on 11-01-2005 10:17 AM
Matthew Fitzsimons
Certified LabVIEW Architect
LabVIEW 6.1 ... 2013, LVOOP, GOOP, TestStand, DAQ, and Vison

Communication Failing with Corrupted Chars . Sql Server 2000 and AS400

Hi Experts,
I am facing this below error after 9 yrs. sql server 2000 and As400 on prod server. while on dev and stage it's running properly. Here username is ABCD, while it's showing BCD
The OLE DB provider "MSDASQL" for linked server "" reported an error. Authentication failed. [SQLSTATE 42000] (Error 7399) Cannot initialize the data source object of OLE DB provider "MSDASQL" for linked server "xxxxx".
[SQLSTATE 42000] (Error 7303) OLE DB provider "MSDASQL" for linked server "" returned message "[Microsoft][ODBC Driver Manager] Driver's SQLSetConnectAttr failed".
[SQLSTATE 01000] (Error 7412) OLE DB provider "MSDASQL" for linked server returned message "[IBM][iSeries Access ODBC Driver]Communication link failure. comm rc=8001 - CWBSY0001 -
User BCD on server does not exist, Password length = 8, Prompt Mode = Never, System IP Address = "xxxxx". [SQLSTATE 01000] (Error 7412). The step failed.
Here ABCD user is also disabling/locking the profile on AS400 server.
When we tried on Dev server, linked server through DSN working properly. Last time when it appeared 2 yrs ago, it resolved automatically. but now more than 10 days passed and still Failing.
Please Guide Me.
Regards,
Manish

So this setup has worked for nine years, and all of a sudden stopped working with this error message? Does not look trivial...
What does Here ABCD user is also disabling/locking the profile on AS400 server mean? Is ABCD able to log in directly on the AS400 box?
One possibility is that the user ABCD has been dropped or disabled, and then there is a bug in the ODBC driver where the first character of the username is distorted in the error message. I note that there are two spaces between "User" and "BCD".
The other possibility is that the AS400 is receiving a login attempt from BCD (or something that ends in BCD with an invisible leading character). This sounds very difficult to troubleshoot...
Erland Sommarskog, SQL Server MVP, [email protected]

Seed Demo Community Failes

Hi Im new To the BPM and SOA suite. I currently have it running however now Im required to configure my server for a tutorial. Im trying to seed a demo community and Understand very little what has to be done. here what ive managed to do:
go to :
Cd c:\Oracle\DemoCommunitySeedApp
c:\Oracle\DemoCommunitySeedApp> setAntEnv.bat
Failed: "C:\Oracle\Middleware\jdev_bpm11g\jdk160_18"\lib\tools.jar does not exist
PLease set your JAVA_HOME to a JDK home.
I then set JAVA_HOME from environment variables to
C:\Oracle\Middleware\jdk160_24
I run the code and the same Failed line of command appears how do I go about it??? how can I make it run??
I actually have no idea where to begin with were do I go into to configure the server? the console? or same place where I configured the domain?
thanks in advance!

Hi
1. Inside this folder c:\Oracle\DemoCommunitySeedApp, or search here for a file named "SOATestDemoApp.ear".
2. Start your SOA Domain. If you have Admin and Soa ManagedServer. Start both the servers. Incase if you have only one AdminServer with soa also deployed, just start admin server.
3. Login into Weblogic Admin Console using something like http://youradminhost:adminport/console. Login with domain username/password. On left side, click on Deployments and on right side, click on Install and follow the screens to install the above "SOATestDemoApp.ear" app to the SOA Managed Server. This is important, as it has to be deployed on SOA Server only. If you have only one admin with soa modules, then deploy to that admin server only. Make sure you hit Activate button or look for this file in deployments list on right side with status as Active.
4. Open a new browser, type this below url. Again host, port should be the one that has soa modules deployed.
http://soahost:soaport/integration/SOADemoCommunity/DemoCommunitySeedServlet
Select the xml file and hit the button, and you should be all set. Go back to console, and under Security -> myrealm -> Users and Groups, you should see all the Demo users and groups.
NOTE: There is no need to run ant script or recompile it, if you already have the EAR file. Read the readme.txt file that came with the zip file.
Thanks
Ravi Jegga

Asynchronous Communication fails

Hi,
I am using Visual Basic.NET 2003 and measurement studio together with National Instruments NI-VISA(TM) Software for Windows. Version 3.0.
Synchronous communication with GBIP instrument (ESG E4438C from Agilent) works fine but I have a problem with asynchronous I/O.
I always get an error like "Unable to queue the asynchronous operation (usually due to the I/O completion event not being enabled or insufficient space in the session's queue)."
What went wrong?
Here is my code:
Private Sub btGo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btGo.Click
AxCWVisa.RsrcName = "visa://149.204.55.39:3537/GPIB0::19::INSTR"
AxCWVisa.Open()
AxCWVisa.WriteAsync("*idn?")
End Sub
Private Sub AxCWVisa_IOC
ompletion(ByVal sender As Object, ByVal e As AxCWVisaLib._DCWVisaEvents_IOCompletionEvent) Handles AxCWVisa.IOCompletion
MsgBox("IO completed")
End Sub
I have tried to Enable Events
AxCWVisa.EnableEvent(CWVisaEventTypes.cwvisaEventIOCompletion)
but all without success.
Thank you for your help,
Markus

Hi Dan!
Thank you for your answer.
I have tried again the EnableEvent method but this fails. Here is my code:
AxCWVisa.RsrcName = "visa://149.204.55.39:3537/GPIB0::19::INSTR"
AxCWVisa.Open()
AxCWVisa.EnableEvent(CWVisaEventTypes.cwvisaEventIOCompletion)
After calling the EnableEvent method I get an exception with the following message:
"Additional Information: Configuring Device
The specified mechanism is not supported for the given event type."
Since this is visaconnection across a network I have tried the asynchronous access at the local maschine - but with the same error message. So the network access should not be the problem.
Using NISpy I get the following Info:
1. viOpenDefaultRM (0x001AEC58)
Process ID: 0x00000A40 Thread ID: 0x000009D8
Start Time: 09:54:12.838 Call Duration: 00:00:00.421
Status: 0 (VI_SUCCESS)
2. viParseRsrc (0x001AEC58,"visa://149.204.55.39:3537/G...",1 (0x1),0 (0x0))
Process ID: 0x00000A40 Thread ID: 0x000009D8
Start Time: 09:54:13.259 Call Duration: 00:00:00.110
Status: 0 (VI_SUCCESS)
3. viClose (0x001AEC58)
Process ID: 0x00000A40 Thread ID: 0x000009D8
Start Time: 09:54:13.369 Call Duration: 00:00:00.000
Status: 0 (VI_SUCCESS)
4. viOpenDefaultRM (0x001AEC58)
Process ID: 0x00000A40 Thread ID: 0x000009D8
Start Time: 09:54:13.369 Call Duration: 00:00:00.000
Status: 0 (VI_SUCCESS)
5. viOpen (0x001AEC58,"visa://149.204.55.39:3537/G...",0 (0x0),0 (0x0),0x001DD1E0)
Process ID: 0x00000A40 Thread ID: 0x000009D8
Start Time: 09:54:13.369 Call Duration: 00:00:00.219
Status: 0 (VI_SUCCESS)
6. viSetAttribute (0x001DD1E0,0x3FFF001A,2000 (0x7D0))
Process ID: 0x00000A40 Thread ID: 0x000009D8
Start Time: 09:54:13.588 Call Duration: 00:00:00.000
Status: 0 (VI_SUCCESS)
7. viSetAttribute (0x001DD1E0,0x3FFF0005,5000 (0x1388))
Process ID: 0x00000A40 Thread ID: 0x000009D8
Start Time: 09:54:13.588 Call Duration: 00:00:00.000
Status: 0 (VI_SUCCESS)
8. viSetAttribute (0x001DD1E0,0x3FFF0007,0 (0x0))
Process ID: 0x00000A40 Thread ID: 0x000009D8
Start Time: 09:54:13.588 Call Duration: 00:00:00.000
Status: 0 (VI_SUCCESS)
9. viSetAttribute (0x001DD1E0,0x3FFF0177,-1 (0xFFFF))
Process ID: 0x00000A40 Thread ID: 0x000009D8
Start Time: 09:54:13.588 Call Duration: 00:00:00.000
Status: 0 (VI_SUCCESS)
> 10. viSetAttribute (0x001DD1E0,0x3FFF0021,9600 (0x2580))
> Process ID: 0x00000A40 Thread ID: 0x000009D8
> Start Time: 09:54:13.588 Call Duration: 00:00:00.000
> Status: 0xBFFF001D (VI_ERROR_NSUP_ATTR)
> 11. viSetAttribute (0x001DD1E0,0x3FFF00B3,2 (0x2))
> Process ID: 0x00000A40 Thread ID: 0x000009D8
> Start Time: 09:54:13.588 Call Duration: 00:00:00.015
> Status: 0xBFFF001D (VI_ERROR_NSUP_ATTR)
Any idea what went wrong?
Thank you for your help!
Markus

When trying to burn files to a DVD (DVD RDL from Memorex) an error message appears saying: Impossible to burn the disk because communication failed between disk player and computer (error code 0x80020022)

When trying to burn files (1,7 GB) to a Memorex DVD, an error messge says: Impossible to burn the disk because communication between disk player and computer failed (error code # 0x80020022).
Is the Memorex incompatible with my i-Mac or what could it be ?
My i-Mac is a 21", Core 2 Duo with 3.06 GHz. RAM is 8Go 1067MHz DDR3.
Thanks.

That message is usually caused by poor media. i.e. poor coating quality.
Mermorex is generally regarded by most users here as poor quality media. So is TDK. Most of us prefer Verbatim, Fuji, Maxell or Taiyu Yuden DVD-R.
Also burn at only 2x or 4x burn speed.

MODBUS-RTU connection with aleatory VISA communication fails

Hi everyone,
I have a big problem that I'm trying to repair since a pair of months. I have a MODBUS gateway connected to my pc via RS-485 in RTU mode. The physical implementation is based on Ethernet cable, so I have two connection converters in both endings of the Ethernet cable that wire each line to its corresponding terminal in a RS-485 connector. On the side of the PC i also have an electronic card to convert RS-485 to USB for connect using a USB port for pc's connection. That card is the model USB-COM485-PLUS1 from the company FTDI chip. I have installed on my PC the drivers of the card that configure a virtual COM serial port for my RS-485 communication. On labview I have programmed my interface for communication using a MODBUS library that was installed previously on my PC (I am using my company PC, because i have this problem on my workplace).
The problem is that, usually, my system works correctly, and the communication is perfect. I read always the holding registers of my gateway, and i can write the control registers without problems, but, some times, the connection spend more time without communication that reading, and after some hours in that conditions, it fall in continuous fail and doesn't work any more since the next day. That problems persists even if i restart the PC or shut it down for a while. By the other side, I realized that when the communication falls it only fall on the reading wire, because even if the reading communication is with continuous fail, i can write on the corresponding registers of my gateway.
I'm sure at 80% that the gateway runs correctly, and I have other installation similar with the same gateway, cable, connections and card working correctly. I tried changing the Ethernet cable, changing the RS-485 to USB conversion card and only when i changed my PC, the problem disappears. So I thought it was a problem of the PC. But some time after I changed the PC, the problem returned. After this, I continue making probes and actually I have the theory that it may be a problem because i have other communications running at the same time in my labVIEW app. I think it may be a problem of incompatibility of drivers or a bridge over different communications that make it fail. Because the pc's where this error disappear has not installed NI RIO drivers.
My LabVIEW program also have a communication via Ethernet with a NI cRIO 9076 chassis. That chassis has a module for PROFIBUS communication, also has a module for thermocouple inputs, a module for voltage inputs and other for voltage outputs. All this modules work correctly always. My theory is that some of this other modules in NI cRIO 9076 chassis may cause a conflict that make my system works wrong. Other things that seems me annoying is that i bought recently a new conversion card for RS-485 to USB connection and it doesn't works on my system, I have other two identical cards and they work correctly, and i know that the new card works also in other systems i have.
The issue I don't understand is that this problem doesn't happend many times and it seems to be aleatory... The fail that the labVIEW return when it can not read the holding registers is a timeout error because of a frame error. It would be illuminating for me if that error where periodic or systematic, but occurs only a day every two or three weeks and the rest of time works properly. But on my company, when this installation will work continuously, it can't have any day of non-work.
So, please, I need help with this Issue, I'm lost int he way of resolving it. Thanks only for read this large post.
Regards,
Joaquín
PD: Please, don't damn my English, it is not my mother tongue, I'm spanish.

First of all, thanks for your quick reply.
I had the USB port save power mode enabled. I have disabled it. Actually my system works correctly so I can't know if the problem has been solved, but i have a new converter card for RS-485 to USB and it doesn't works, i have other two that work properly but the new only writes, just like when i have the problem commented. So, I think that if i solve the problem with the new card, i can be sure that I will have solved my connection problem. The new card is configured with the same options that the others, except by the port number, i configured COM 3, COM 4 and COM 5 respectively.
By the other side, when I said that I think cRIO interferes in MODBUS communication I mean that the only things that changes in PC's that correct the problem are that they have not installed the FPGA module or the RIO drivers. And once i changed my PC, the problem was solved since I installed this module and drivers, moment when the problem reappeared.
Thanks again

TCP communication fails

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