Mitsubishi Electric MELSEC iQ-R Series User Manual page 58

Check item
Does the setting value of the watchdog timeout match the
specifications of the slave node?
Does the I/O structure of the parameter and the actual structure of the
slave node match?
Is the production inhibit time too short?
Is the production inhibit time too long?
Is the parameter written?
Is not the circuit load high because of the multi-master configuration?
Is not the circuit load high because of I/O communications or message
communications?
Is any communication error code stored in 'Other slave communication
error information' (Un\G1154 to Un\G1217)?
Can master function error information be read by reading
communication error information with the master function (message
communication)?
If the above action does not solve the problem, perform the hardware test to check for hardware failure. ( Page 52
Checking the Module Status)
Unable to communicate with the master node (slave function)
When the communication cannot be performed with the master node, check the following items.
Check item
Is the communication cable connected to the connector of the
RJ71DN91 firmly?
Is the same communication speed set to every node?
Is the terminating resistor connected?
Does the number of I/O points of the slave function match the
parameter setting of the master node?
Is the parameter setting of the master node the polling and the UCMM
support (group 3)?
Is 'I/O communication request' (Y11) on?
Is not the circuit load high because of the multi-master configuration?
Is not the circuit load high because of I/O communications or message
communications?
Is any communication error code stored in 'Slave function
communication error information' (Un\G1153)?
*1 This item is for when the parameter setting method is "Program" and the auto communication setting is off.
If the above action does not solve the problem, perform the hardware test to check for hardware failure. ( Page 52
Checking the Module Status)
4 TROUBLESHOOTING
56
4.5 Troubleshooting by Symptom
Action
Check the following parameter and set the correct value.
Check the following parameter and set the correct value.
Check the following parameter and set the correct value.
Check the following parameter and set the correct value.
Create a correct parameter and write it.
Set or change a constant scan for all the master nodes and decrease the frequency
of communications for stable communications.
Decrease the frequency of I/O communications or message communications for
stable communications.
Take action according to the communication error code.
Take action according to the read communication error information (the
communication error code and the general DeviceNet error code).
Action
Connect the communication cable to the connector of the RJ71DN91 firmly.
Set the same communication speed to every node.
Connect the terminating resistor.
Match the number of I/O transmit/receive points with the master node.
Set the parameter setting of the master node to the polling and the UCMM support
(group 3).
*1
Turn on 'I/O communication request' (Y11).
Set or change a constant scan for all the master nodes and decrease the frequency
of communications for stable communications.
Decrease the frequency of I/O communications or message communications for
stable communications.
Take action according to the communication error code.
• When using the engineering tool: [Basic Setting]  [Master Function Parameters]
 [Slave Node Information]  [Watch Dog Time out]
• When not using the engineering tool: "Watch Dog Time out" of the slave node
information in buffer memory 'Master function parameters' (Un\G468)
• When using the engineering tool: [Basic Setting]  [Master Function Parameters]
 [Slave Node Information]  [Input Byte Size], [Output Byte Size], [Input Word
Size], [Output Word Size], [Input Dword Size], [Output Dword Size]
• When not using the engineering tool: "Number of byte modules", "Number of word
modules", "Number of double word module" of the slave node information in buffer
memory 'Master function parameters' (Un\G468)
• When using the engineering tool: [Basic Setting]  [Master Function Parameters]
 [Slave Node Information]  [Production Inhibit Time]
• When not using the engineering tool: "Production Inhibit Time" of the slave node
information in buffer memory 'Master function parameters' (Un\G468)
• When using the engineering tool: [Basic Setting]  [Master Function Parameters]
 [Slave Node Information]  [Production Inhibit Time]
• When not using the engineering tool: "Production Inhibit Time" of the slave node
information in buffer memory 'Master function parameters' (Un\G468)