Mitsubishi Electric MELSEC iQ-R Series User Manual page 136

When communications with the devices cannot be performed by GX Configurator-PN
The following lists the actions to be taken if communications with the external device (RJ71PN92 or IO device) cannot be
performed from GX Configurator-PN.
Check item
Is the cable connected correctly?
Has an error occurred in the RJ71PN92?
Is the hub used correct?
Is the IP address of the RJ71PN92 correctly set?
Are the IP address segments different between the personal computer and
external devices (RJ71PN92 and IO devices)?
Do the IP addresses of the personal computer and external devices
(RJ71PN92 and IO devices) overlap with each other?
Is the device (such as Ethernet-equipped module, external device, hub, and
router) on the line replaced by the one having the same IP address before an
error occurs?
Has an IP address outside the range been specified?
Is the network overloaded?
*1 A device on Ethernet has a table of IP addresses and their corresponding MAC address, called ARP cache. When a device on the line
is replaced by the one having the same IP address, the MAC address in the ARP cache is different from that of the replaced device;
therefore, communications may not be normally performed. The ARP cache is updated by resetting the device or after a while. The time
varies depending on the device.
5 TROUBLESHOOTING
134
5.5 Troubleshooting by Symptom
Action
Connect the cable again.
Perform troubleshooting using the LEDs. ( Page 122 Checking with LED)
• Check if the hub used satisfies the standard. ( MELSEC iQ-R
PROFINET IO Controller Module User's Manual (Startup))
• Power off and on the hub.
When an operation is performed on the "Devices on the Network" window or
the network diagnostics is performed in GX Configurator-PN, an execution
request is issued from GX Configurator-PN to the IP address set in the
module parameter of GX Works3. For this reason, write the settings of GX
Works3 (IP address of the RJ71PN92 and other settings) before such
operations.
When an operation is performed on the "Devices on the Network" window or
the network diagnostics is performed in GX Configurator-PN, communications
are performed between the personal computer and the RJ71PN92. Thus, set
the IP addresses of the personal computer and external devices (RJ71PN92
and IO devices) to the same segment.
Contact the LAN network administrator to eliminate the overlap of the IP
addresses of the personal computer and external devices (RJ71PN92 and IO
devices).
Take any of the following actions when the device (such as Ethernet-equipped
module, external device, hub, and router) on the line is replaced by the one
having the same IP address.
• Wait until the ARP cache is updated. (The wait time varies depending on
the device).
• Restart all the devices on the line.
Consider the following and specify a correct IP address.
• The IP address should start with a number from 1 to 233, excluding 127.
• No space should be included in the IP address.
Connect the IO device with unstable communications to the RJ71PN92 one-
on-one and check if the communication status is improved.
When the communication status is improved, the network may be overloaded.
Take the following actions.
• Check and correct the settings of the RJ71PN92, for example, set the
communication cycle longer, to reduce the communication load.
• Check if a large amount of unrelated data is received in broadcast. If it is
received, isolate the network or take other actions.
*1