Programming question utilizing timers

Corolling · Aug 28, 2021

Hi all,

Wondering if this is possible.
I have a cyclic timer setup to turn a switch on for 3 mins every half hour. I'd like to have it turn on if my ph is lower than 8.4. if ph is higher, do not turn on switch.

Is this possible?

I'd also like it to not turn on if ph is 8.0ish or my ALK is lower than 10. Is this possible?

Thank you. I did read the documentation, but couldn't find this possibility.

Many thanks

Lasse · Aug 28, 2021

It would be possible - however you will work with two different nominal values of pH. This demand that you make one virtual pH probe based on your real pH probes measurement and have a nominal value of 8.4 in one of the probes and 8 in the other. Do you use a KH director?

Sincerely Lasse

Corolling · Aug 28, 2021

Lasse said:
It would be possible - however you will work with two different nominal values of pH. This demand that you make one virtual pH probe based on your real pH probes measurement and have a nominal value of 8.4 in one of the probes and 8 in the other. Do you use a KH director?

Sincerely Lasse

I sure do!

How do I make a virtual probe? Do I have to use the control on the p4 to create it?

Thanks Lasse!

Lasse · Aug 28, 2021

Yes - it is the only way with p4 - P3 have a virtual control panel too,

Page 70 here explain how to do with virtual probes.

Your normal probe - nominal value 8.4. Virtual probe nominal value 8

Create a PL port x : timer x AND (normal probe - increase)
Create a new PL port y: PL x AND (virtual probe - decrease)

Knit this to socket Z This will do that your socket is on if timer x is on and pH below 8.4 but not below 8

How to implant you demand that not turn on if KH is below 10 - I cant say for the moment - have to check at work) But I think you can set the nominal value to 10 kH

Create a new PL - PL z; PL y AND KH decrease. Knit that to you socket instead of PLy

Sincerely Lasse