Yaskawa MP920 User's Manual Design - Manual (Page 83)

3.3 Power Failures
3-9
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3.3 Power Failures
This section explains the processing when an MP920 power failure occurs.
3.3.1 Power Failure Detection
Table 3.3 shows the start methods used when an MP920 power failure occurs.
The MP920 can select two types of startup: Continuous operation and new operation. The
selection of continuous operation or new operation is made on the MPE720 System Defini-
tion Window.
For details on the MPE720 operation method, refer to the Machine Controller MP900/
MP2000 Series MPE720 Software for Programming Device User’s Manual
(SIEPC8807005).
* Ns (power loss decision time) is defined on the MPE720 System Defini-
tion Window.
Table 3.3 MP920 Start Modes
Length of
Power Failure
Continuous Operation/
New Operation
Start Method
0 to 20 ms − Operations continue.
20 ms to Ns*
(Power loss) When continuous operation
is selected After the CPU is reset, no self-diagnosis is
performed, and operations continue.
When new operation is
selected After the CPU is reset, self-diagnosis is per-
formed, and the new operation starts.
Ns* or more When continuous operation
is selected After the CPU is reset, no self-diagnosis is
performed, and operations continue.
When new operation is
selected After the CPU is reset, self-diagnosis is per-
formed, and the new operation starts.