AutoGen_2621519

Is it possible to use the same front multiple times (with the same TAG) ?

Yes. But it won't work as expected. On the other hand detecting a falling edge of the same signal multiple times doesn't make sense either.

Use auxiliary bit and then use this bit in all the other places.

Your original post shows the same memory tag for both -|N|- LAD instructions.

That _can_ and _will_ cause problems.

1st rung in the network compares the current value of the memorized state of the top tag.  If the current value of the top tag is low and the last value of the top tag was high, the output of the instruction goes high, AND the current top tag gets assigned to the bottom tag (the memory tag).

On the 2nd rung, if the top tag is low, the bottom tag is also low from where it took on the value of the top tag in the -|N|- instruction, so the output does not go high.

On the 2nd rung, if the top tag is high, the bottom tag will also be high (from the 1st rung).  So, the 2nd rung will never activate and will cause many people to lose their minds simply because the memory tag was reused.

Save the state of the tag's transition to an intermediate tag and use that everywhere else it is required in the logic.  You do not need logic to preset it at startup, nor reset it based system state changes (like auto<->manual<->startup).  It will just work.

AutoGen_2621519

Hello everyone,

Is it possible to use the same front multiple times (with the same TAG) ?

Like this :

Second edge instruction will not work - first will write to edge tag affecting second call

you can creatre a temp variable which is driven by edge and use it multiple times after edge detect.

    Input                                            BTmp
-----|P|--------------------------------------()
   Edge-bit

Note: edge bit must not be written anywhere else in the program. P instruction writes old value of its argument there.

You can imagine edge instruction as something shown below:

Input              Edge_Bit                          BTmp
-----||--------------|\|-------------------------------()
               |                                               Edge_Bit
               |----------------------------------------()



so if you use the same bit for another edge instruction it will not work (it will not see edges)