When the PLC is turned on, the display screen is lit.
Note that the screen can display messages only after you download HMI displays to the PLC. If you have not downloaded displays, check the screen by pressing the 'i' button for a few seconds to enter Information Mode. If no text appears on the screen, the PLC may not be receiving turned on.
If your PLC does not turn on
Check that the power supply's voltage is in the permissible range in accordance to the technical specifications for your model.
Check the PLC's connections. The +24VDC must be connected to the + V terminal, and the ground connected to the 0V terminal.
Make sure that the 24VDC output power supply is connected to a functioning AC power source.
Check your fuses or circuit breakers. These must allow power flow.
Make certain that the power is ON.
If you have checked all of the above, and the PLC does not turn on, contact your local distributor.