Specifications

54 GX Configurator-PN

ween the PLC program and the PROFINET Controller. By default this mechanism is not activated

(LIVE_WORD_X =0)

The following scenario applies:

By default the LIVE_WORD_Y register is set to 0, meaning that no check is activated.

To activate the mechanism, PLC sets LIVE_WORD_Y to 1 or to any value different from 0

The IO-controller reads the LIVE_WORD_Y value in an interval of 500 ms. If the value is identical

three consecutive times (1.5s) and differs from 0, the IO-controller will consider the PLC as no longer

running. In this case IO-controller sets the IOC_STS.bit17 for indication.

If activated this watchdog mechanism is the only way for the IO-controller to detect that a PLC pro-

gram is currently running. In this case any attempt to download a new configuration will display a

warning message to alert the end user.

Once the mechanism is activated the PLC has to write a new value each 500 ms. The mechanism

can be stopped at any time by writing 0 again to the LIVE_WORD_Y register.

Each 500ms the IO-controller also copies the LIVE_WORD_Y read value in the LIVE_WORD_X re-

gister If the PLC does not read the same value after a maximum of 1 second, the PLC can consider

that the IO-controller is no longer running and start any appropriate action.

2.1.6 PLC and PROFINET Controller States (RUN/STOP)

PLC

STATE

PROFINET

Controller

STATE

Comment

RUN

PROFINET stack is in RUN.

IOPS and IOCS have status GOOD

Input data are updated in the High Speed Area