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28 FUNCTIONS
28.3 Tracking Transfer
28.3 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.
• The control system CPU module sends tracking data to the standby system CPU module 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 standby system CPU module 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 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.
• During an online change or when a stop error has occurred, tracking transfer is performed only for system data. ( Page
457 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 461 Batch transfer)
• When "Process Control Extension Setting" is enabled, the tracking transfer setting is automatically
configured in detailed settings. The range of the file register specified to the system resource of the optional
process control extension setting is registered to the tracking block No.64. ( Page 460 When the
"Process Control Extension Setting" is enabled)
When a tracking transfer is not performed, the possible causes are the following:
• The standby system CPU module has been powered off or reset.
• Hardware failure of the CPU module has occurred.
*1
• An error has occurred in the redundant function module.
*1
• A WDT error has occurred.
*1
• 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.
Control system Standby system
Sending tracking data
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