Tracking Transfer - Mitsubishi Electric MELSEC iQ-R Series User Manual

26.3

Tracking Transfer

This function transfers the control data from the control system to the standby system and maintains the consistency of the
data in the two systems to continue operation of the redundant system when a failure or an error occurs in the control system.
Control system
• The CPU module of the control system sends tracking data to the CPU module of the standby system before the END
processing. The tracking data includes device/label data, special relay (SM), special register (SD), PID control instruction
information, and system data.
• The CPU module of the standby system receives the tracing data, and then reflects the received data on the device/label
memory.
• Tracking transfer is performed in both of backup mode and separate mode.
• Device/label data can be divided and transferred as required. To transfer device/label data within a desired range, set a
range of global devices to be transferred and whether to transfer local devices/global labels/local labels/module labels
(extension base unit) for each tracking block and turn on the tracking triggers (SD1667 to SD1670) assigned for each
tracking block.
• Up to 1M-word device/label data can be transferred in one scan.
• When a stop error has occurred, only system data is transferred. ( Page 392 System data)
• In the CPU parameter, "Tracking Device/Label Setting" is set to "Transfer collectively" by default. Thus,
tracking transfer is performed without setting the parameter. ( Page 397 Batch transfer)
• When a program file is converted with the process control extension setting enabled, "Tracking Device/
Label Setting" is automatically set to "Detailed setting". In the tracking block No.64, the range of the file
register specified in the system resource of the process control extension setting is registered. When the
system is operating in backup mode, the tracking transfer trigger (bit 15 of SD1670) corresponding to the
tracking block No.64 automatically turns on at every scan. ( Page 395 When the "Process Control
Extension Setting" is enabled)
When a tracking transfer is not performed, the possible causes are the following:
• The CPU module of the standby system has been powered off or reset.
• Hardware failure of the CPU module has occurred.
• An error has occurred in the redundant function module.
• A WDT error has occurred.
• Tracking cables has been pulled out or disconnected.
*1 When the tracking communication line properly works, "Link-up" (event code: 00100) may be stored in the event history.
26 REDUNDANT FUNCTION
388
26.3 Tracking Transfer
Standby system
Sending tracking data
*1
*1
*1