[:=] Non retentive assignment Structured Text

Hi All

I have tried to use the following code to reset a tmr.

if Cycle.St & not(CycleStart_Rst) then
Tmr_Main.Reset [:=] 1;
CycleStart_Rst := 1;
elsif not(Cycle.St) then
CycleStart_Rst := 0;
end_if;

TONR(Tmr_Main);

As you can see the tmr.reset bit is set using a non retentive output [:=] as per RS help files

However the Tmr remained in the reset state until I manually cleared the bit. I then had to add the following code after the TONR(Tmr_Main); instruction to allow the timer to run after being reset.

if Tmr_Main.reset then
Tmr_Main.reset := 0;
end_if;

It is therefore clear form this that the [:=] instruction is causing the bit to retain its value.

Has anyone else encountered this problem?

Thanks

Can you post a link or post an abstract to the manual.

Structured text does not have an OTE instruction, but you can achieve the same results using a non-retentive assignment.
data_bit [:=] BOOL_expression;

Can be found under OTE in instruction Help

I read the following -

So it only works within an SFC then, not when using structured text in an AOI