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CTI 2572 Installation and Operation Guide
83
CHAPTER 8. TROUBLESHOOTING
8.1. General Troubleshooting Techniques
If you experience a problem in communicating with the module, consider the following
troubleshooting guidelines:
1. Make sure that the module is operational (see Section 5.2 below). Common problems include not
logging in the module to the PLC and not loading the PLC parameters properly. If you notice a
problem in this area, you must correct it before proceeding further.
2. Check the network cabling (see Section 5.3 below). If you are using 10baseT, the LB indicator
must be lit. If you are using 10base2, make sure that the cable is connected and terminated
properly. If you are using a transceiver attached to the AUI port, make sure that the transceiver is
receiving power. If you are experiencing intermittent problems, ensure that the 802.3 limitations
for segment length and number of segments have not been exceeded. You may also need to check
the cable quality with the applicable tester.
3. Check the network address settings. The Network ID portion of the address must match for all
nodes on the local network and the Host ID portion must be unique. Use the Ping utility to
determine whether TCP/IP at the lowest level can send and receive data from the module.
Observe the module LED’s to determine if signals are being sent and received.
4. If your local network is connected to other networks via a router, check to ensure that the router
network addresses are set properly and that all hosts on the local network are using the same
subnet mask, if subnetting is used. See Appendix D.
5. If you are using a computer application to access the PLC via the 2572, check the application for
errors in sending the commands. You should also check to determine if the 2572 PLC Server
Error Word (available if you started the 2572 PLC network server via PLC logic) contains any
“information only” error values related to the application commands. See PLC Server Error
Codes on page 102. A common problem is requesting data outside the configured PLC address
range.
6. If you are using the 2572 Client function, check the applicable error word for an error value.
7. If you are unable to determine the problem using the above techniques, you may need to capture
network traffic using a network analysis tools. In the past, this usually required an expensive
network “sniffer”. Today you can acquire an inexpensive analyzer program from CTI that can
assist you in capturing and interpreting the captured data.