Mitsubishi Electric CC-Link IE Basic Reference Manual page 48

When a station is repeatedly disconnected and reconnected
Check the following:
■Ethernet
Check item
Are the Ethernet cables inserted to each slot until they click?
Do the used cables conform to the Ethernet standard?
Is any Ethernet cable disconnected?
Is there any source of noise near the Ethernet cables?
Are there any external devices or hubs having an error? Or, is there any lost
*2
packet?
Is a correct hub, which is compatible with the communication speed of the
connected master station/slave stations, used?
Is the response of built-in Ethernet functions such as FTP, socket
communications, and SLMP communications slow, an error, or not
*4
returned?
*1 Check the communication status of Ethernet by referring to the areas for storing such as the CRC error count and the received packet
checksum error discard count. For details, refer to the manuals of each series.
*2 If the load is heavy, data communications may stop depending on the hub. In that case, consult the manufacturer of the device used.
*3 When a personal computer and CPU module have been reconnected to the switching hub, or the switching hub has been replaced, it
may take some time to read the MAC address. In this case, retry the transmission later or power on the hub again.
*4 Check the communication status of Ethernet by referring to the areas for storing such as the simultaneous transmission error detection
count and the number of times that data are not read due to receive buffer full. For details, refer to the manuals of each series.
■CC-Link IE Field Network Basic
Check item
Is the timeout time setting of the master station too short?
Are there any slave stations having an error?
Is CC-Link IE Field Network Basic being simultaneously executed at a
different network address on the same line?
Are data communications with other Ethernet devices being performed on the
same line?
Is any of the following function being executed?
• Access from GX Works3/GX Works2 (such as ladder monitor)
• Latch function
• Data logging function
Are slave stations divided into too many groups?
Is a slave station that the response is slow belonged to a group of shorter link
scan time? Or, is a slave station that the response is fast belonged to a group
of longer link scan time?
9 TROUBLESHOOTING
46
9.2 Troubleshooting by Symptom
Action
• Lock the Ethernet cables securely.
• Check that the Ethernet cables are correctly connected to the external
devices and hubs.
Check the specifications of the Ethernet cables used.
Replace the disconnected Ethernet cable.
*1
Keep the Ethernet cables away from the source of noise. Or, use the cables
resistant to noise.
• Reduce the number of cascade connections to three or less.
• Take actions, referring to the manual for the device having an error or
packet loss.
Replace the hub with a correct one.
• Stop the function. Or, modify settings. For example, extend the execution
interval and decrease the execution frequency of the function.
• Change UDP/IP communications to TCP/IP communications, or add resend
processing.
Action
Increase the timeout time of the master station.
Perform troubleshooting for the slave station having an error.
Separate the network and configure two CC-Link IE Field Network Basic lines.
Separate the network for other Ethernet devices from the CC-Link IE Field
Network Basic line and configure the CC-Link IE Field Network Basic line.
Stop the function. Or, modify settings. For example, extend the execution
interval, decrease the execution frequency, or reduce the range of the
function.
Reduce the number of groups as much as possible (for example, organizing
slave stations of 16 or less into one group).
Refer to manuals for slave stations used to check their reference response
times.
Check and correct the group number of the corresponding slave station in the
network configuration setting.
*3