step 7 small question

my dear friends,
plz tell me how can i compare 2 words? I dont want to convert the words to integer.

Since WORD data types are logic patterns, rather than values, you then need to start thinking about using logical operators rather than arithmetic operators such as 'compare'.

Fortunately there are only a few logical operators: AND, OR, XOR.
Let's consider the result of these on two WORDs with identical and different bit patterns -

AND Result if identical: Output is identical to both inputs
AND Result if different: Output has unpredictable pattern
OR Result if identical: Output is identical to both inputs
OR Result if different: Output has unpredictable pattern
XOR Result if identical: Output is all '0'
XOR Result if different: Output has unpredictable pattern

I don't know what you want to do with the result of this operation. Even in the only case where you can predict the output I'm not sure of the most appropriate method to detect whether this condition exists or not?

Regards

Ken

(PS : Can someone check and confirm or deny my logic? The more I re-read it, the more doubts I have about it!)

No problem

Hi,

you can not do it in LAD or FBD but with STL it is not a problem. You can use 16 bit integer comparison.

Example:

L WORD1
L WORD2
==I //If values are same RLO=1

It does not matter if it is WORD or INT

Good luck,
MM

I would just do the compare in STL. There is no typechecking in STL so dont worry that one is an INT and the other a WORD or they are both WORDs.

edit: crossposted with maitomies.

my friend,
i want to compare 2 words then if they are equal, then for example turn on one light.

Hello sahayan;

You just need to add a =Q0.0 to Maimonides' example.

Whenever you have a doubt on STL, just program your network in LAD, in this case use a EQ_I box with 2 integers and an outout, then go to View and display the network in STL. It should give you a good idea of the STL syntax required in your application.




Hope this helps,
Daniel Chartier

On DC's example I would do:


A(
L MW2
L MW4
==I
)
= Q 0.0


You can then have other conditions included in the logic then

thank you very much my dear friends. i got your answer