9
PROCESSING TIME FOR REDUNDANT SYSTEMS
9.2 System Switching Time
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9.2 System Switching Time
System switching time is the time required from detection of the switching condition for the
control system to the start of the new control system CPU's control.
Calculate the system switching time using the following expression.
* 1: This indicates the system switching processing time for the case where the signal-flow memory is
set to “No tracking” in “Tracking settings” of “Redundant parameter”.
* 2: This is 0 ms when tracking processing is not complete.
* 3: The maximum system switching time is shown.
Tsw = + T m + Trc (ms)
Tsw : System Switching time
*3
Trc : Reflection time for tracking data using the standby system
CPU module
T m: CC-Link IE Controller Network, MELSECNET/H, CC-Link,
PROFIBUS-DP automatic refresh time (T m)
(Refer to the manual for the network module being used.)
: When the extension base unit is connected
• Signal flow memory is not tracking-transferred: 31.5ms
• Signal flow memory is tracking-transferred: 12.5ms
When the extension base unit is not connected
• Signal flow memory is not tracking-transferred: 20.5ms
• Signal flow memory is tracking-transferred: 1.5ms
Diagram 9.1 System Switching Timing
System A
System B
System
switching
request
Run program
Detect cause
of system
switching
System switching processing time (21ms)
Run program
CC-Link IE Controller Network, MELSECNET/H,
CC-Link, PROFIBUS-DP automatic refresh time (T m)
Execute Tracking transfer process (Trc)
*2
*1
Control
system
Standby
system
Standby
system
Control
system
0
System
switching
time (Tsw)