Network Status; Conditions For Starting And Stopping Remote I/O Communications; Communications Errors - Omron CJ Series Operation Manual

5-2

Network Status

5-2-1 Conditions for Starting and Stopping Remote I/O
Communications
• If the communications power supply to the Slave Units is turned ON, remote I/O communications will
start when the power supply is turned ON to the Controller or when the Controller is reset. In Regis-
tered Slave Unit Participation Standby Mode, communications will not start until all registered Slave
Units are participating in the network. (Refer to Registered Slave Unit Participation Standby Mode on
page 5-18 for information on the Registered Slave Unit Participation Standby Mode.)
• I/O Communications Manual Startup Mode can be set from the CX-Integrator so that remote I/O com-
munications do not start when the power supply is turned ON. Remote I/O communications will not
start until *_IOCycleStartCmd (Remote I/O Communications Start Switch) changes to TRUE.
• In Communications Error Communications Stop Mode, all remote I/O communications will stop if a
communications error occurs in any Slave Unit. At this time, *_CommStopSta (Communications Error
Communications Stop Flag) in *_UnitSta (Status) will change to TRUE. To use Communications
Error Communications Stop Mode, turn ON the ESTP (Communications Error Communications Stop
Mode setting) pin on the DIP switch on the front of the CompoNet Master Unit.
Note All communications will stop if a Verification Error occurs when the Registration Table is enabled or if a Slave
Unit Duplicated Address Error occurs.
5-2-2

Communications Errors

A communications error occurs when a Slave Unit cannot return a normal response to a communica-
tions request from the Master Unit.
The following are the main causes of communications errors:
• There is a malfunction at the Slave Unit itself.
• The communications cable to the Slave Unit is disconnected.
• The communications power supply is OFF.
• The Slave Unit cannot receive correct data because of noise.
When a communication error occurs at a Slave Unit, the NS indicator on the front of the Master Unit will
light and the seven-segment display will show d9. At the same time, the representative communications
flag *_SlavComErr (Communication Error Flag) in *_UnitSta (Status) will change to TRUE.
Remote I/O Communications Operation When a Communications
Error Occurs
If a communications error occurs for a Slave Unit when the ESTP (Communications Error Communica-
tions Stop Mode setting) pin on the DIP switch on the front of the Master Unit is set to ON, all remote
I/O and message communications will stop. At this time, (*_CommStopSta (Communications Error
Communications Stop Flag) in *_UnitSta (Status) will change to TRUE.) If the pin is set to OFF, remote
I/O communications will continue. When the cause of the communications error is removed, the Slave
Unit is automatically restored to the network. It is not necessary to restart the Master Unit or cycle the
power supply.
CJ-series CompoNet Master Unit Operation Manual for NJ-series CPU Unit (Cat. No. W493)
5 Remote I/O Communications
5
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