Hello Guys,
I have a motor which has 3 pins (Open | Ground | Close) for heating system and i would like to use a PID with Arduino but i need it with relais because the motor is for 230V.
Example: Outsidetemperature < Watertemperatur --> open motor with relais until Watertemp is = Outsidetemp.....
I only find exaples with analog motors.
Can anyone help me with this pleaseeee 
Thank you Progjonny 98
Use 2 relays for Open and Close. If the motor should open then activate the relay that connects mains to the Open connector.
Do not connect the motor Ground to the Arduino Gnd. The Arduino is separated from mains by the relays.
I am already that far but when i only open and close it than it is a P - and not a PID Controller so the motor always opens and close and will not stop in the way i PID can do this
Post that code or read it yourself.
It should be easy to replace the analog control of a motor with code for opening and closing a relay.
a7
PID shouldn't have to enter into your considerations given the brief statement of functionality you give in your original post.
Looks like ON and OFF.
On until condition, off until other condition.
Hysteresis maybe, but no need for close loop PID control of anything.
Or (tots likely)'you are omitting something or I am missing you point.
a7
It can open per 1° steps but only with digital signal 230V
That's why I suggest 2 relays. One for Open, one for Close, and if both are off then the motor is off as well.
Have a hysteresis with the output of your PID. Turn the motor on only if a certain threshold is exceeded. See 3-state controller.
No need for a PID. Bang-Bang controller with a little hysteresis around the set point. It has worked in HVAC systems for 100 years.
do you have a link for me for this controller
Only in the German Wikipedia: Dreipunktregler
What does the system heat?
Why do you need to use PID?
Looking at your prior thread, the only way you can know the position of the valve is to fully close it and then keep track of every open/close action you do.
Given that, you can use your set point and actual temperature to run a PID. You can set output limit to 140 and the PID output will represent how many seconds of opening the valve should currently have. Based on how open the valve currently is (which you're keeping track of), you open or close the valve to match.
Given how long it takes to move the valve, you should set the update time for the PID to be rather longer too.
Hi, @progjonny98
Are the terminals actually marked, Open, Gnd, Closed ?
If it is a 230Vac? motor then the middle will not be marked Gnd...
Can you please post make/model of the unit?
Can you please post an image(s) of the unit, including its terminal block?
Thanks.. Tom.. 
Hi,
I would not connect the centre to gnd, that uses active and neutral.
Mains systems do connect neutral to gnd, but at the fuse/meter box.
The motor will be a 2 phase motor with a phase shift capacitor that is connected so the motor changes direction when either end of the capacitor is made active.
Like this;
Tom...
ok but how do i contorl the motor now`? with the Arduino
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