P = proportional
I = integral
D = derivative

Explaining that in detail is not easy so here is a short and hopefully understandable explanation without any scientific parts

The target value controller will always try to reach and hold the temperature that you have set. Of course when your system is under load the temperature will rise and the controller has to speed up the fans to come back to your settings. It might be easier when you imagine P as power. This value has no measurement unit and provides the amount of power to work against the rising temperature. A low value means the fan will work slower to achieve your setting while a larger value will be more aggressive and provides more power to the fan to come back to the target temperature. So when you select a high value you will have a quick changes but at the cost that your fans will change its speed faster which can be annoying.

I can not tell you a standard value since such a thing does not really exist. You will have to play a bit around with it.

The I part works over time. It adds some power step by step every second to assist the P value. This value is ideal to adjust the regulation speed. So if you think the target value controller could work a bit fast you maybe want to use a larger I value instead of playing around with P.

So with P you do the rough adjustment while I is for the subtleties. The D value ist not available in this controller since using it is next to worthless.

Hysteresis is some kind of limit where the controller is still active although given its parameters it should not be active anymore.

Let's say you have a configuration where your fans will start to run at 30°C and we are currently at 33°C and the fans cool down your system. So normally at 29,9°C the fans would stop which could cause the following problem: If they stop it might take only a few seconds before we are back at 30°C and the fans will spin up again, a few seconds later we are back at 29,9°C and so on. So the fans would permanently start and stop.

With the hysteresis value you can solve that problem. If you use a hysteresis of 2°C the controller will work down to 28°C so the fans will stop at 27,9°C. Now you have a buffer of 2°C until you reach the 30°C and the fans will work again.

We have a roadmap for the basic functions which must be integrated. So far the software sensor had no priority for us but since several people asked for it in the last weeks we moved it a bit up in the list. I'm not able to tell a date but I guess it will be in there soon.

Can anyone shed some more light on how this should work? maybe provide some example values.

i want to control pumps and radiator fans with the set point controller using water out / case ambient delta

thanks

also what are the units of measure for Hysteresis, P, I, D and Reset time(D). min/max values would be nice as well if possible.

so far i have:

Value Unit of Measure Min Max
Hysteresis Degrees 0 10

P ??? 0 30,000
I ??? 0 30,000
D ??? 0 30,000
Reset time (D) ??? 0 60

my settings for radiator fans controlled by water temperature. -> fans always running with minimum power.

Citation

also what are the units of measure for Hysteresis, P, I, D and Reset time(D)

this values does not have a unit. this are abstract values to control the speed an the precision of the controller

thanks. those settings help.

in your opinion, should the pump always run at 100% or should it vary based on some temp setting?

i was planning on using set point for the pumps and another set point for the radiator fans.