S7-300 Add Integer

Hi all

This should be an easy one !

I need to increment a value in a data block by 1 each time a flag is high.
If i set up an ADD_I with the data address at IN1 and 1 at IN2 it should add 1 to the value when EN is enabled by the flag. Trouble is, it adds 1 to it on every scan of the program while EN is high.
How can i make it just count once each time the flag goes high.

I could use a counter but i need to count up into the 100,000s and the counter only counts to 999

Thanks in advance for any help

USE FP positive edge detection.

If your counts exceed 32k then you will need to use a double word:
Paste the following code into a blank network in stl mode and it will display in ladder (assuming the jump label is not duplicated elsewhere of course)

Simon, you need to use L#1. Otherwise MD100 will flip over at 65535.

Edit: Never mind. You can use an INT if you explicitoly use the +D instruction. I usually use STL and write it like this:

L MD 100
+ L#100
T MD100

If I do this:

L MD 100
+ 100
T MD100

it will flip at 65535.

Yes, I usually type it in STL as you would but in this case I just posted the STL version of the ladder.

Thanks guys, it worked a treat :nodi: