POINT
Precautions for monitoring the QCPU redundant system
(1) A system alarm may be detected when the system is switched in a redundant system.
When Q redundant setting is made | : "450 Path has changed or timeout occurred in redundant system." |
When Q redundant setting is not made : "402 Communication timeout. Confirm communication pathway or modules."
However, even if the error occurs, the GOT automatically resumes monitoring and there are no problems in the monitoring operation.
(2)The system alarm is displayed when the system is switched due to cable disconnection etc. (when the path is changed).
The system alarm is not displayed when the system is switched by the user.
(3)When connected to the remote I/O station, the GOT can monitor only the following GOT functions.
Monitoring function | System monitoring function |
(4)When connected to the remote I/O station, the GOT does not allow the PLC CPU clock of the master station to be set in the clock setting of the utility.
The master station clock will not change even if the clock setting is made.
Use GX Developer or a similar software to set the PLC CPU clock of the master station.
(5)When the Q redundant setting is not made, the GOT does not automatically change the monitoring target even if system switching occurs in the redundant system. When the GOT is connected to the standby system, data written to a device are overwritten by the data of the control system, failing to be reflected.
In this case, when data are written to a device in the standby system normally, the system alarm "315 Device writing error. Correct device." is not detected.
(6)For monitoring the QCPU redundant system when connecting to MELSECNET/H, use QCPU of function version D or later, with the upper five digits later than "07102".
Also, use GX Developer of Version 8.29F or later.
(7)A message "Unable to communicate with CPU." is displayed when the system switching occurs while an option function such as the ladder monitor is used.
(8)In the MELSECNET/H connection or MELSECNET/10 connection, when the control station of the MELSECNET/H network or MELSECNET/10 network fails and is taken over by a station outside the QCPU redundant system, the timeout is detected as the system alarm.
If this occurs, the monitor display speed may slow down.
(9)In the direct CPU connection, the GOT fails to automatically change the monitoring target in the following cases.
•When the power supply to the CPU where the GOT is connected is OFF
•When the cable connecting the GOT with the CPU is broken
•When the tracking is disabled
(10)If the Q redundant setting is made for a system that is not a QCPU redundant system, no error occurs at the start up of the GOT and the GOT operates normally.
In this case, if an abnormality (such as powering OFF, or communication timeout error) occurs at the PLC CPU for which the Q redundant setting has been made, the PLC CPU may operate in a different way from the monitoring target change mode that was set in the Q redundant setting.
(11)If the QCPU redundant system is in the debug mode, do not make the Q redundant system setting for the GOT side when connecting the GOT.
4. HOW TO MONITOR REDUNTANT SYSTEM | 4 - 7 |
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PREPARATORYFORPROCEDURESMONITORING 2
RANGESETBE
DEVICE CANTHAT 3
RANGEACCESS MONITORINGFOR 4
MONITORTOREDUNTANTSYSTEM HOW 5
CONNECTIONBUS 6
DIRECTTOCONNECTIONCPU 7
LINKCOMPUTER CONNECTION 8
ETHERNETCONNECTION