Troubleshooting By Symptom; Communications Cannot Be Performed With The Connected Device - Mitsubishi Melsec-L Series User Manual

14.6

Troubleshooting by Symptom

The following describes how to troubleshoot for each phenomenon. When an error occurs in the E71, identify the
cause with the programming tool. (
14.6.1
Communications cannot be performed with the connected
device.
The following table lists how to troubleshoot the problem when the E71 cannot communicate with the connected
device.
Check item
Is the RUN LED of the E71 on?
Does the connected device conform to the Ethernet
standard?
Is the cable securely connected?
Is the network parameter mode set to "Online"?
Does the communication data code (ASCII or binary)
setting match with that of the connected device?
Has the initial process been completed normally? (Is Initial
normal completion signal (X19) on?)
Was a device on the line (such as an E71, connected
device, hub, and router) replaced by the one with the same
IP address?
*1 Devices on an Ethernet network contain the IP to Mac address mapping, called an "ARP cache". If a device on a line is
replaced by another device with the same IP address, the MAC address contained in the "ARP cache" and the MAC
address of the replaced device do not match; therefore, communications may not be performed normally. The "ARP
cache" is updated when the device is reset or after a certain period of time. The time varies depending on the devices.
*2 If the communication data code setting is different between the E71 and the connected device, error codes that are not
found in the error code list may be returned to the connected device. When receiving data with different data codes, the
E71 cannot decode commands normally. The E71 returns an error response according to the communication data code
setting. (
*3 If the LG and FG terminals of the power supply module on the E71-connected station are not connected, the
communication line may be closed (disconnected) due to noise; therefore, communications with the connected device
may not be performed.
If the action above does not solve the problem, check for an error in each communication process and take corrective
action. ( Page 196, Section 14.6.4 to Page 202, Section 14.6.10)
194
Page 189, Section 14.2)
Reset the CPU module. If resetting the CPU module does not turn on the
RUN LED on the E71, the hardware of the E71 may be faulty. Replace the
E71 and restart all the connected devices that were performing
communications with the own station.
Replace the device with one conforming to the Ethernet standard.
(
• Securely lock the cable.
• Check the wiring. (
Set the network parameter mode to "Online".
(
If the data code settings do not match, data cannot be sent or received
because the connected device cannot normally decode commands.
same data code as that of the connected device in "Communication Data
Code" of the Ethernet operation setting.
(
• If Initial normal completion signal (X19) is off, perform the initial process.
• If the initial setting of the programming tool is same as that of the initial
Restart all the devices on the line.
Page 104, Section 10.6.2 (1) (e), Remark)
Page 56, CHAPTER 5)
Page 60, Section 6.2)
Page 64, Section 7.1.2)
Page 65, Section 7.1.3)
( Page 246, Appendix 3)
process program, delete the initial process program.
Action
*1
*1
*2
Set the