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Erratic TCP/IP connection using crossover cable (cRIO-9025))

Hello,

 

We have an application running on a cRIO-9025 and sending data to a client application running on a laptop. LabVIEW 2011 is used on both side.

 

When the laptop and cRIO are communicating via our router, everything runs smoothly. Problems occur if the laptop and cRIO are connected using a crossover cable, the TCP/IP connection is getting very erratic.

 

The problem we are facing seems to be the same as describe here: http://digital.ni.com/public.nsf/websearch/FD24D98FF428F21686256B64007FB6C1

 

The suggested solution did not work on our side. We tried to put the cRIO in half-duplex mode and also to put the both (cRIO and laptop) in half-duplex mode without improvement. We also tried with different laptops (1 using winXP and the other using win7) without improvement as well.

 

Anyone have faced this issue before?

 

Thanks!

 

Vincent

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What erratic behavior are you seeing? Are you having trouble connecting to your cRIO? Or are you having data transfer issues? 

 

Have you gone through this KnowledgeBase, and verified the IP addresses of your computer are set to what you expect? 

Applications Engineer
National Instruments
CLD Certified
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Hi,

 

         One of my project, i used the same controller with cRIO 9118 chassis and 7 modules, even i used the windows7 OS and LabVIEW 2011. Actually it is very good controller. i think u get the problem with configuring network address.Pls try the following steps, it may help u,

 

1. use the branded ethernet cross cable(don't use the manually crimped cable. it may avoid the connection issue).

2. After using the branded cable. first u detect the controller in MAEx(Measurement & automation expo).

3. Suppose u not able to detect the controller, just format it and try again. u wil get the ip address as 0.0.0.0 . For example configure the controller network addr as,

               ip addr : 192.168.1.100,

              subet mask : 255.255.255.0,

              gateway : 192.168.1.1

 

primary and sec DNS addr not required.

 

pls do the same in the PC also,  except ip addr (for ex: 192.168.1.101 remaining are same). do it in ipv4. don't choose ipv6.

 

4. rebuild the code and deploy it again.

 

i think attached example code will help u.

 

i gave the idea for only network config.

if u have any other issue, kindly reply me again.

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use the eth0, eth1 is secondary

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Hello,

 

Thanks for taking time to have a look at my problem...

 

Our Application is acting as a server on the cRIO side and is sending data using TCP/IP VIs to a client (laptop). When connected to the router, the data flow goes pretty fast and we do not have any overflow. If we connect the cRIO to the laptop with a crossover cable, we still are able to send data to the laptop but at a VERY much slower rate. We then run in overflow very quickly as the data is acquire much faster than can be send on the crossover cable.

 

We have made several researches before posting so we indeed have looked at the mentioned KnowledgeBase. We are pretty confident about our cable and network settings.

 

We tried to connect the server and client using a switch and I didn't help (IP are 192.168.1.105 and .106). The interesting part is that as soon as we plug the switch into our router, things work perfectly, full speed.

 

Thanks again!

 

Vincent

 

 

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Fine ok. i think u might know this There are many types of cross cables available with different speed ratings. it catagory name is cat6,7. it may help to speedup.

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Hey Vincent, 

 

The Router adds two main things to the mix. It can negotiate the issue you posted initially between the network cards not communicating properly, and it will also act as a DHCP server for both the Laptop and the cRIO. 

 

My guess is that since you specified the IP's as .105 & .106 that you've set them statically, both on your laptop (through the network and sharing center for a windows machine), and on the cRIO (through MAX). Is that correct?

If not, the router may be assigning the correct IP addresses to either the laptop or the controller, allowing them to communicate properly.

 

If they are both static, I would assume that the router is then negotiating right connection between the two network cards for you. Since, it seems that the system is having trouble using the crossover cable, have you tried connecting the controller to the laptop with a normal cat 5 cable?  I wonder if that will allow the network cards to negotiate the connection correctly. 

Applications Engineer
National Instruments
CLD Certified
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Hello Zach,

 

When we first notice the problem, the laptop and cRIO were connected with a normal cat 5 cable. Our first guess was to try with a crossover cable to resolve the issue...

 

We will work on that again this week to try to find a solution.

 

 

Thanks again!

 

Vincent

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One other thing to look at are the protocols that are enabled on your laptop Ethernet interface.

 

The only protocol you should need to communicate with the cRIO is Internet Protocol (TCP/IP).

 

Other protocols can be very chatty on a network, performing broadcasts to detect peer systems. You could disable Client for Microsoft Networks, File and Printer Sharing for Microsoft Networks and any sort of Apple protocols. If you turn these off and then plug the laptop back into a regular LAN, you may lose services that you are used need for that scenario. The solution would be to add a dedicated Ethernet interface in the laptop for the cRIO connection.


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