User manual

Toolbox 32 User Manual 1.47d www.cse-semaphore.com/mykingfisher
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205
Automatic Changeover
A standby CPU will turn into a duty CPU if:
• The standby CPU cannot hear any communications on the I/O bus and the communications bus for
approximately 5 seconds.
• The duty CPU loses communications on the communications bus or the IO bus and forces a
changeover.
• The value of the system register #YEXCEP is set to 16#800 from ladder logic. Note: a processor will not
swap back to standby mode until it has been the duty processor for at least 60 seconds.
• A Utilities, Advanced, Swap Master command is issued from Toolbox to either the duty or to the
standby CPU. Note: if the CPU that requests the swap gets no response from the other CPU, no action
is taken as it is assumed there is no other CPU present.
• Ladder logic is disabled while downloading firmware drivers or after a cold start or firmware download.
Note: the CPUs will not swap over if ladder is manually disabled using the Toolbox command Utilities,
Advanced, Enable/Disable, Disable Logic Processing.
• A warm start command (Utilities, Warm Start RTU) is issued to either CPU when the standby CPU is in
duty mode. This causes both CPUs to start up in their default state (the CPU in the even slot will become
the duty).
Replacing CPUs
CPUs can be replaced after powering down the RTU or while the RTU is still running (not recommended).
When a CPU is replaced, the RTU will automatically warm start itself.
• The standby CPU (installed in an odd slot address) can be replaced at any time without losing new data
if it is running in standby mode (L2 LED is flashing).
• The duty CPU (installed in an even slot address) can be replaced at any time but any new data that is
received by the standby CPU (now running in duty mode) will be over written. To avoid losing the new
data, the replacement duty CPU can be forced to start up in standby mode, allowing the standby CPU to
copy the new data to the replacement duty CPU. To force a CPU to start up in standby mode, set the
system register 2471 Hex to 1 (using the menu Utilities, Advanced, Read/Write System Reg). This will
cause a one-shot start up in standby mode and then the system register 2471 will be automatically
cleared. After waiting about 5 minutes to ensure all the data has been updated in the replacement duty
CPU, the CPUs can be swapped over (if desired) using the command Utilities, Advanced, Swap
Master.
Configuring Redundant CPUs
• Redundant CPUs are configured one at a time by plugging one CPU into the backplane and then
downloading firmware (optional), drivers (optional) and the RTU configuration. After removing the first
CPU, the second CPU is plugged into the backplane and the same software is downloaded again. Note:
please specify slot 0 when configuring all CPU ports to avoid confusion. Different ladder logic can be
loaded in the duty and standby CPUs if required.
• If Ethernet communications are being used, different IP addresses can be used for the Ethernet port of
the duty CPU and the Ethernet port of the standby CPU. If the same IP address is used for both CPUs,
only the duty mode CPU keeps its Ethernet port active. Both CPUs can keep their Ethernet ports active if
they are configured with different IP addresses and #YMODE.4 is set to 1 using ladder logic in the
standby CPU. This will allow both CPUs to be polled while connected to the same LAN or a second
(redundant) LAN can be used for the standby CPU.
• Install one configured CPU in an even slot address and the other configured CPU in an odd slot address.
The even slot CPU will become the duty and the odd slot CPU will become the standby.
• To force a changeover between the redundant CPUs or monitor the changeover status using ladder
logic, please see the system register #YEXCEP.
• Note: If using firmware older than 1.41a, a redundancy driver (that matches the firmware version) needs
to be downloaded into each CPU before downloading the RTU configuration.