Please help with code for DS18B20

[fratello]

I will make a small program to retrieve the serial from the device and place it to the code.

It's in post #22. Enjoy !

[astanapane]

Hi Fratello,

here we are step by step.

i did retrieve the serial number from the DS18B20. I placed it to the code and worked.

I put two sensors and now i have INT and EXT temp. I can say that they are really close the temp from two sensors.

Now i would like to ask you if the code is for the temp only or the thermostat.

I have place two LED on the porta.2 and porta.3, but i dont see any light.

Do i need to configure anything else?

[fratello]

Good job ! Keep it so !
You need to add these lines :

If V < TargetTemp - Hyst then ' Below Target temperature - Hysteresis
PORTA.2=1 ' Activate Warm Output
PORTA.3=0 ' Deactivate Cold Output
EndIf

If V > TargetTemp + Hyst then ' Above Target temperature + Hysteresis
PORTA.2=0 ' Deactivate Warm output
PORTA.3=1 ' Activate Cold Output
EndIf

just in front of

GoSub SelectSign ' +/blank/- Sign
GoSub DisplayTemp ' Temperature to LCD


Goto MainLoop ' Do it forever

[astanapane]

Hi Fratello,

your help is much appreciated.

I will follow your instructions this afternoon. The code is working really well and the temperatures are very close to other circuits i have.

Thanks a lot!!!

[astanapane]

hi again,

i place the code at your suggestion, and it is ok,

the problem is that the low and high indications are flashing they are not stable on when they are activated.

is that normal?

[astanapane]

ok i found the problem,

if i place small current LEDs they are flashing when the port is activated.

If i place an LED more than 25mA then it stays light and stable.

But!!! i have seen an other problem. The INT sensors seems to stack some times, and gets unstack if there is a rapid change on the EXT sensor.

Have anyone noticed that? Do you think that this is Sensor problem?

thanks.

[astanapane]

Ok after all i found out that it was the sensor problem.

According to the outputs on the ports for high and low indication, the problem exists.

Once i place a low current 10mA it does not light but flashing very low.

If i place an led more that 20mA then it fully light up.

I dont know if anyone has the same problem.