Logical NOT not working

[Panther 0]

New to GX Works2 (Structured Text), and encountered an interesting puzzle that the logical NOT didn't work as expected.

Ex. NOT 0 turns out to be 0, while 1 is expected.

Kindly refer to the GX Works2 monitor screen attached, and advise what could be wrong.

Thanks for your time and help.

[kaare_t 155]

[NOT] works fine in GX Works2. Is the PLC in RUN? Are you sure that the output variables (M2010, M2011, Y121, Y122) here are not used anywhere else so that they are reset later in the sequence?

[Gambit 326]

Are you sure the programming is running? or in the plc ?

[Panther 0]

Thanks for your prompt help, really appreciated.

Indeed, the program is not running as pointed out.

After double checking and verify the program is running by turning on/off a physical light, it works fine.

Apologies for the silly question, how to check the program running in GX Works 2?

In fact, prior to encountering this issue, the program ran as expected (again, by the physical light).

And I did the same way (and the program is not running as pointed out by you):
Stop All Monitoring -> Build the program -> Stop the PLC (Toggle the run switch) -> Clear Memory -> Write the program  -> Toggle PLC switch to run -> Start Monitoring Again

[Gambit 326]

A download or online change of the compiled program should be enough. 
When it's a new program file you will have to download the parameter and reset the PLC as the PLC parameters have changed.

Edited 22 Sep 2017 by Gambit

[Panther 0]

Noted with thanks, Gambit.

Wish you and kaare_t a nice weekend ahead!