Academic Company Events NI Developer Zone Support Solutions Products & Services Contact NI MyNI
5 ratings:
 3.20 out of 5     Rate this Document

How Do I Connect to a LabVIEW Real-Time (RT) Target with a Crossover Cable?

Primary Software: LabVIEW Modules>>Real-Time Module
Primary Software Version: N/A
Primary Software Fixed Version: N/A
Secondary Software: N/A
Hardware: PXI/CompactPCI>>Controllers, Compact FieldPoint, CompactRIO, FieldPoint, Compact FieldPoint

Problem:
I am connecting over a crossover cable to a LabVIEW Real-Time (RT) target from a Windows machine. I am unable to communicate properly with the controller. Am I configuring the system properly?

Solution:
Crossover Cables:
A direct connection between the computer and a Real-Time controller requires a crossover cable. Most Ethernet cables are straight (patch) cables, not crossover cables. To determine the type of cable you have, look at the 8 colored wires that are visible through the clear-plastic connectors on both ends of the cable. If the green and orange wire position is swapped between one end and the other as seen in, then the cable is a crossover cable; however, if the green and orange wires are in the same relative positions on both ends of the cable, then it is a patch cable. The 1000baseTX/T4 (Gigabit) standard specifies that crossover cables have all wires swapped in position.


10baseT / 100baseTX Crossover Cable


10baseT / 100baseTX / 1000baseTX/T4 Crossover Cable

Troubleshooting the Connection:
A common indicator that you are using the incorrect cable is the LINK LED, which will not light on the Real-Time controller if you have the wrong cable connection. This is not foolproof; however, since the LINK LED may not light for other reasons.  Additionally, if the computer in use has multiple network adapters, be sure that the only adapter that is enabled is the one which the device is plugged into.  See the related links section below for additional information.

Computer Network Settings
When making a direct connection to a LabVIEW Real-Time controller using a CAT-5 crossover cable, you must first disable DHCP on your Host PC. Without disabling DHCP, you may find that some communication with the controller is not working properly. For example, the system may fail to appear in Measurement & Automation Explorer (MAX), or the system may fail to install software on the system. Below are instructions for various operating systems.

Windows 95/98/Me
  1. Go to Start » Settings » Control Panel » Network.
  2. On the Configuration tab, highlight the entry for your network card (the one with the icon of a green board next to it) and click the Properties button.
  3. Select the Bindings tab and confirm that your network card has bindings to TCP/IP. Click the OK button.
  4. Select the TCP/IP entry and click the Properties button.
  5. On the IP Address tab, select Specify an IP Address.
  6. At this point, you may select your own IP Address and Subnet Mask. A typical set of settings for a standalone computer are an IP Address of 192.168.0.1 and subnet mask 255.255.255.0. Press the OK button and exit the Network control panel.
  7. Reboot the computer.
Windows NT/2000
  1. Go to Start » Settings » Control Panel » Network.
  2. Select the Protocols tab and highlight TCP/IP. Click the Properties button.
  3. On the IP Address tab, select Specify an IP Address.
  4. At this point, you can select your own IP Address and Subnet Mask. A typical set of settings for a standalone computer are an IP Address of 192.168.0.1 and subnet mask 255.255.255.0. Press the OK button and exit the Network control panel.
  5. Reboot the computer.
Windows XP
  1. Go to Start » Control Panel.
  2. Switch to Classic View if necessary.
  3. Select Network Connections.
  4. Right-click on Local Area Connection, and select Properties.
  5. Select the General tab and highlight Internet Protocol (TCP/IP). Click the Properties button.
  6. On the General tab, select Use the following IP Address.
  7. At this point, you can enter your own IP Address and Subnet Mask. A typical set of settings for a standalone computer are an IP Address of 192.168.0.1 and subnet mask 255.255.255.0. Press the OK button and exit the Network control panel.
  8. Reboot may not be necessary in Windows XP.
Windows Vista
  1. Go to Start » Control Panel.
  2. On the left hand side, switch to Classic View.
  3. Select Network and Sharing center.
  4. On the left hand side, select Manage network connections.
  5. Right-click on Local Area Connection, and select Properties.
  6. Under the Networking tab, highlight Internet Protocol Version 4 (TCP/IPv4). Click the Properties button.
  7. On the General tab, select Use the following IP Address.
  8. At this point, you can enter your own IP Address and Subnet Mask. A typical set of settings for a standalone computer are an IP Address of 192.168.0.1 and subnet mask 255.255.255.0. Press the OK button and exit the Network control panel.
  9. Reboot may not be necessary in Windows Vista.
If the RT controller has already been configured with a static IP address, make sure that the controller's settings are consistent with the IP settings on your host computer. The host and RT controller will need unique IP addresses that are on the same subnet.

 

For the example above, an IP address of 192.168.0.2 and a subnet mask of 255.255.255.0 would be on the same subnet.  If the controller has not been configured, you could also use the Suggest Values button in MAX to select a valid IP address and subnet mask now that the host computer has a static IP address.

Related Links:
KnowledgeBase 2IHG7FZ8: Poor Network Performance in LabVIEW RT When Connected to Another Computer via a Crossover Cable
KnowledgeBase 1XGF6R4U: I Cannot Connect to My LabVIEW Real-Time Target on the Network
KnowledgeBase 2WTAMTPK: Measurement and Automation Explorer Does Not Auto-Discover my Real-Time System under Windows XP?
KnowledgeBase 4D5CCQJQ: Why Does My cRIO Controller Not Show Up in MAX?

Attachments:





Report Date: 03/21/2001
Last Updated: 10/29/2008
Document ID: 27K9UNKN

Your Feedback! poor Poor  |  Excellent excellent   Yes No
 Document Quality? 
 Answered Your Question? 
  1 2 3 4 5
Please Contact NI for all product and support inquiries.submit