help with omron counter instruction

[Weivreif]

hi guys, just new to plc.
im using cj1m cpu22
currently working on a program that measures distance by means of a rotary encoder

if my understanding is correct encoders will count the number of turns then it will do some math to convert the number of turns to a unit of measurement like centimeters.

so heres what I did, I used a reversible counter input the conditions for incrementing and decrementing the counter. then I will use a math function to multiply the present value of the counter by a certain number.

my question is how do you program it in a way that the multiplicand would be the present value of the counter?

for example counter set value is at 50 but present value is 20, how do you use that present value to perform operations with it. like math operations and such

also how do you use to always on flag, and what is the function of cf-bit. thanks, appreciate evry help i can get.

 

[markgettys]

Great question, the answer is very long...
I suggest that you High Speed Counter, it is not a beginner solution.

Take your counter, make the set value 9999, (#9999 if you are using BCD)you can then compare CMP the count present value to a Data memory that contains the set value that you need (50). When equal or grater than set a bit that preforms your logic.

Then you do need to worry about what resets the the count value.

The CJ has floating point math avaiable USE it. *F, /F, +F you will get Real Numbers as a result. The decimal point will float as the name suggests. Use <F, >F, or gerater then = so on for your compare.
This will allow you to work in engineering units, cm instead of pusles.

Happy to email you an example in CXP is you want.

 

[Weivreif]

thanks a lot mark. I might need a copy of that program. you can email it to me at [email protected]