General

If the duration of the outage is less than the power supply filtering time, it has no effect on the program, which continues to run normally. If this is not the case, the program is interrupted and power restoration processing is activated.

Filtering time:

PLC

Alternating Current

Direct Current

BMX CPS 2000

BMX CPS 3500

BMX CPS 3540T

BMX CPS 4002

10 ms

-

BMX CPS 2010

BMX CPS 3020

-

1 ms

Illustration

The following illustration shows the different power cycle phases.

Operation

The following table describes the power outage processing phases.

Phase

Description

1

On power outage, the system saves the application context, the values of application variables, and the state of the system on internal Flash memory.

2

The system sets all the outputs into fallback state (state defined in configuration).

3

On power restoral, some actions and checks are done to verify if warm restart is available:

  • restoring from internal Flash memory application context,

  • verification with memory card (presence, application availability),

  • verification that the application context is identical to the memory card context,

If all checks are correct, a warm restart is done, otherwise a cold start is carried out.