Tools for Troubleshooting Ethernet-Connected Smart Cameras
Posted by Steve Maves on Tue, Dec 21, 2010 @ 02:34 PM
Smart Cameras have universally adopted the low-cost, high-speed Ethernet networking standard and TCP/IP communications for both up-front programming and for in-process data collection. These standard methods lower cost for everyone and allow easier troubleshooting and root-cause analysis. Here are some of the tools and information that have helped me understand Ethernet, TCP/IP, and troubleshoot problems.
First, a foundation of knowledge is an excellent place to start. Many of us have picked up Ethernet and TCP/IP knowledge “on the fly” during our busy work lives; I know I have. It is a good idea to occasionally step back and do some reading to fill in the gaps. I would strongly recommend Neal Allen’s book Network Maintenance and Troubleshooting Guide, Second Edition. The aim of the book is to lay a foundation for understanding the principles of network operation, and then get to actual problem solving scenarios based on that knowledge. This book was an eye-opener for me, filling in a lot of gaps in my knowledge of TCP/IP networks. I find myself going back to this book again and again.
When troubleshooting communications problems with Smart Cameras that have already been deployed and working for some time, the problems are usually physical, such as cables or connectors that have been damaged. A simple visual inspection along the entire path of networking cable from the Smart Camera to the data collection PC or programming computer will sometimes reveal problems. If not, a cable tester is a very handy tool to have around. Devices like the Fluke DTX series of cable testers can give you confidence that Ethernet cabling has been installed correctly, and should be used wherever Ethernet is installed on the factory floor.
Moving up to more complex problem solving at the TCP/IP level, Packet Capture programs can be useful for capturing unexpected behavior for offline analysis and troubleshooting. One such program is Wireshark, a freeware program which can be downloaded from the web and installed on any PC. Capturing all the data of interest can be a challenge because of the way modern switches operate. The best tool to capture data either at a Smart Camera, or at a data collection computer, is a “Network Tap.” This tool can be inserted anywhere into an Ethernet network and allows the capture PC to see all the data going across the wire at a specific point. Many vendors sell tools like this, including Fluke and Network Critical.
With the right combination of knowledge and the appropriate tools, engineers responsible for network installation and uptime can understand normal network behavior and any deviation from that behavior. This allows them to quickly solve problems, and in some cases, even anticipate them.
View all the ways you can export machine vision data and images over Ethernet in the IMPACT software suite. Download the free emulator software.