Repeating timers with comparators

[Abby]

Hello, 

I need to make a program in Visilogic that based on repeating 15 minute timer.  when the 15 minutes is completed the ph. value will be read and if its above 10.5ph it will decrease a valve turn by 1%. If its between 10.5-8.5 it does nothing. If its below 8.5ph it will increase the valve turn by 1%. After this the timer restarts. 

I am having a lot of trouble with the timer and I thought of using greater thans, within range and less thans. but I don't think this is the best way. 

 

Any help is greatly appreciated

 

[kratmel]

You do not post any info about your setup.

Please try to use something like this ladder. Please note - Visilogic operate with integer value. And if you read PH 10.5 - you must convert it to 105 integer (or use float numbers in ladder and float compare function for correct operation).

[Flex727]

On 7/8/2022 at 9:59 AM, Abby said:

I am having a lot of trouble with the timer

Self-resetting timer, as in kratmel's rung #1, is a very useful tool.

And kratmel smartly recognizes that the direct contact of TD 1 is the same as a positive transition contact in this case, thus you don't need to waste the limited number of positive transition contacts available.