I use pl7 pro ver4.3sp1 structured text language programmed on plc tsx p57303m ver 5.5,when I test run,I found "re" and "fe" work not corect.I think maybe my software is old ,who tell me why and help.thanks.

 

Are you using the FE- or RE-functions on bits in a word? Because these functions don't work on those bits (Wx:x0), only on real bits (Bx) and input-/output-signals (Ix/Qx).

 

Instructions RE and FE only works with bits %I %Q and %M .
And these bits mustn't be use by Set Or Reset