@Phaedrux
After connecting everything and trying a PID tune because of the very large heat capacity of the aluminum plates the initial climb of the temp was very slow. The set temperature was 40 degrees. After around 4 minutes the bed reached that temperature and power was turned off. The temperature kept climbing until 113 degrees!
Also because of the large load it's not good to turn it on and off very frequently I tried lowering the power factor and the PWM frequency but its still too fast. So I thought that I will turn to bang bang control.
Apart from the initial peak temperature the control works very fine because it keeps the temperature with around 1 degree accuracy which is quite acceptable for this large format (and it will become more accurate when closing the printer [less loses] ).
For now my heat up procedure goes like:

1. Set bed temperature to 30 degrees
2. Wait when it peaks at around 62 degrees
3. Set bed temperature to 60 degrees
4. It turns on every around 3 minutes for 15 seconds and then off again and goes from 59.9 to 60.8
   Is there a way to set for example a set time for a heater to be on?
   Also is there a wait function?
   In order to write a heat up g-code.
   Thank you in advance!

Thank you very much!

The bed is a 1m^2 aluminum plate with 15mm height and the heating element is oven resistors 18 of them each one around 600w so we have a total of around 10kW. I have 5 thermistors one in the center of the bed and 4 of them around 300mm from each corner of the bed. I haven't yet powered them up I was just asking if I can eliminate the average power of the resistors and give some delay for the heat to spread (with for example half time on half time off during the heat up procedure).

Thank you for your quick reply! I know that function but my problem is that I don't want the heating element to be on for more than a few seconds because it reaches very high temperatures.

I have a duet 2 wifi and I want to control my heatbed with SSR. I have made the connection and everything works ok, but I want a maximum on time for the SSR during continuous heating at the beginning of the heating procedure when the SSR is always on (for example when going from 25 to 60degrees before the PID procedure turns on). I want that for heat spread across my bed. Is there a way to program duet do that? Thank's in advance!

Thank you very much now all axis home perfect.

I have changed some of my connections and now i can successfully home my x and y axis but not the z axis (again i have the problem of the motor not stopping despite the fact that the led on the induction sensor is light up) (and the induction probe for the z axis is connected to the E0 stp pin threw a schottky diode).

Also i have updated my duet wifi firmaware to version 1.21 and now when i just try to move an axis this message appears:
This appears for the x axis:
M120
G91
G1 X10 F6000
M121
Error: G0/G1: insufficient axes homed
Error: Pop(): stack underflow!

I have tried that and again it doesn't stop when the switch is triggered.

All of the x y and z axis fail to home