Similar S5 code gives different result while using input/s-flag

[cezary]

Hello there!

I've got one little problem with S5-135U program that's driving me crazy.

I've got those two segments:

A I 0.0
AN S 12.1
= S 12.0
A S 12.0
S S 12.1
AN I 0.0
R S 12.1
NOP 0
***

A S 0.0
AN S 13.1
= S 13.0
A S 13.0
S S 13.1
AN S 0.0
R S 13.1
NOP 0
***

It's a classic positive edge detection. The thing is, when I use I0.0, it works great, but when I replace an input with S-Flag, it stops working. When online and translated to ladder, it shows that S0.0 is open and closed at the same time:

Any ideas why is that so? S-flag area in this CPU wasn't used before (directly or indirectly), so I don't expect any conflicts here.

 

[L D[AR2P#0.0]]

Probably this: