Please help with code for DS18B20

[astanapane]

ok,

there is no problem with the DQ link.

there is no bad component DS18B20. I have put two new DS18b20 that are working on a different circuit.

How do i know the DS serial number? Do i need to get the serial number from my DS18b20 and place it to the code?

[astanapane]

Sorry for asking so many things, i just be so close to make it work.

So do i need to read the serial number for each sensor and place it inside the code?

do i need to follow that http://www.picbasic.co.uk/forum/cont...r-nine-of-them?

and then get the serial number from the DS?

[fratello]

Read first page of THIS topic !!!

[Ioannis]

Every device on 1-Wire network has in its internal EEPROM a unique serial number that has to be known to the host.

Otherwise the host can not find the device and communicate.

On Maxim site there is an application note about a way to automatically find the devices on the local 1-wire network. SO every time your controller powers up, it makes an device scan and stores the found ID's or serial numbers.


The second method is to find the serial numbers by your self and store them in the internl EEPROM of the controller.


AN187, is the Note that describes the method

Ioannis

[astanapane]

Fratello and Ioannis,

thanks for your help.

Now i understand. It is very similar to RFID serial number. You can retrieve the serial from the device.

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

i will come back with my results.

Best Regards,

[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.

[fratello]

The function on thermostat it's made with R (4k7 - from PIC port), transistor (BC547), relay (from collector to plus).

[astanapane]

Thanks Fratello,

i havent test with any transistor, because normally it works with an indication of LED. The ports can handle 100mA. I thought that would work like that.

This week i will be in Vienna and then i will be in America for some Seminars. So i wont be able to test in my lab the code or a circuit.

I will get 3 uLED 3,2 touch from Sparkfun and i will try to make and complete the circuit for RFID that i have started in addition to codelock circuit.

[Ioannis]

Which display did you ordered? the 4D 3.2" touch screen?

Ioannis

[astanapane]

yes this one Ioanni.

http://www.sparkfun.com/products/10089

[astanapane]

i'm facing the same problem with the LED output pulses.

Is there anyone has the same problem? I cannot fix it.

Once the temp goes closer to the SET temp, the output seems to have pulses before it light the LED at its level.

It looks like the PIC sends pulses at the very close set temp and once it comes to the action, lights the LED.

To be more specific.

Lets say we SET the TEMP at 22 C. and .10 C. the plus and minus from 22 C.

If the display goes to 21.6 or 21.8 the indicator LED flashes very low with pulses.

If the TEMP goes to 22.20 then the LED lights.

Please let me know if anyone of you having the same problem. To program i use the PIC KIT 2.

thanks a lot.

I would like to say that i have test the circuit with Transistor also and Resistor 4,7K.

But at the point close to the set TEMP the led keeps flashing, and once is reaching the (emaple 22.20 C) it goes stable active.

[Ioannis]

The comparisson is done with the program code in post #88?

Ioannis

[astanapane]

Hi Ioannis,

Yes, i have added the lines Fratello told me in order to activate the outputs.

[Ioannis]

It should not do this. The code has some kind of hysteresis which prevents the play at he output.

What if you increase this hysteresis?

Ioannis

[fratello]

I made tens of this thermostat, for all my friends, relatives....without troubles. Maybe it's time to show us Your schematic !

[Acetronics2]

May we ALSO see your FULL code ???

...

Alain

[astanapane]

Yes sure, i will upload the code soon, and i will also make a small video if you want.

On the output, i have done the following configurations.

1) only an LED
2) light the LED through resistor.
3) light the LED through a transistor.

In case number 1. the 3MM LED does not go ON but it flashes very low with some pulses, it is not noticeable. (the 5 mm goes on)
In case number 2. the LED works just fine
In case number 3. the LED works just fine

My question is, if anyone understands why it does not light up straight from the PIC (pin) output with no transistor or resistor.

thanks a lot and sorry for the trouble

[Ioannis]

I can only assume an overload with some kind of interference with something else around...

I would never load directly PIC output pins.

Ioannis

[fratello]

My opinion : MUST connect the LED trough resistor (R=U/I ; where U=5V and I depend on LED colour) ...

[astanapane]

it is strange because most of the times PICs can directly drive loads until 100mA. The leds get something like 10mA or less. The thing is that it looks like some pulses coming up from the pin. Can i test the PIN without any load on it with an oscilloscope? IF i have pulses then can we identify what the problem should be?

[Archangel]

it is strange because most of the times PICs can directly drive loads until 100mA. . . .

Ok I took this comment out of context . . . 100 ma if all port pins have a load on them distributed across the entire port . . . 25ma max on a single output pin. . . unless I misread the data sheets.

[astanapane]

Fratello,

i have changed your code a little bit, only a very simple thing in order to have two outputs.

instead of this

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

i used this

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

EndIf

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

If V2 < TargetTemp - Hyst then ' Below Target temperature - Hysteresis
PORTA.3=0 ' Deactivate Cold Output
EndIf

If V2 > TargetTemp + Hyst then ' Above Target temperature + Hysteresis
PORTA.3=1 ' Activate Cold Output
EndIf

and now i have two outputs. Very simple change but useful.

Regards,

[Ioannis]

I used to manipulate the ports directly, but once I had a problem and suspicion have fallen on the technique among other things.

So, I now only use HIGH and LOW commands even if these eat a little program memory just to be sure.

If your code is small enough to fit in one page then you probably can use direct port control.

Ioannis

[electron]

Thanks for support !!!!
First code (post #18) return this result : 28 CA C6 48 1 0 0 A7
Second code (post # 22) return : CA C6 48 01 00 00


In the code that I write now I use something like this :
"Init1
OWOut DQ, 1, [$55, $28, $FE, $DA, $3E, $0, $0, $C1, $4E, $FF, $FF, $7F]
OWOut DQ, 1, [$55, $28, $CA, $C6, $48, $1, $0, $0, $A7, $48]
OWOut DQ, 1, [$55, $28, $CA, $C6, $48, $1, $0, $0, $A7, $B8]
OWOut DQ, 1, [$55, $28, $CA, $C6, $48, $1, $0, $0, $A7, $BE]
Pause 1000
OWOut DQ, 0, [Temperature.Byte0, Temperature.Byte1, 0, 0, DS18B20_12bit]


Init2
OWOut DQ, 1, [$55, $28, $FE, $DA, $3E, $0, $0, $C1, $4E, $FF, $FF, $7F] 'SENSOR 2 !!!!!!!!! not reading yet !!!!
OWOut DQ, 1, [$55, $28, $CA, $C6, $48, $1, $0, $0, $A7, $48] 'SENSOR 2 !!!!!!!!! not reading yet !!!!
OWOut DQ, 1, [$55, $28, $CA, $C6, $48, $1, $0, $0, $A7, $B8] 'SENSOR 2 !!!!!!!!!
OWOut DQ, 1, [$55, $28, $CA, $C6, $48, $1, $0, $0, $A7, $BE] 'SENSOR 2 !!!!!!!!!
Pause 1000
OWOut DQ, 0, [Temperature.Byte0, Temperature.Byte1, 0, 0, DS18B20_12bit]


Main
OWOut DQ, 1, [$55, $28, $CA, $C6, $48, $1, $0, $0, $A7, $44] ' Start temperature conversion Sensor 1

WaitLoop:
While not DQ
Wend

OWOut DQ, 1, [$55, $28, $CA, $C6, $48, $1, $0, $0, $A7, $BE]
OWIn DQ, 0, [Temperature.Byte0, Temperature.Byte1]
GoSub Convert_Temp
GoSub DisplayTemp

Part2
OWOut DQ, 1, [$55, $28, $CA, $C6, $48, $1, $0, $0, $A7, $44] ' Start temperature conversion Sensor 2

WaitLoop2:
While not DQ
Wend"



I hope it's good...will see !

I try to read serial number in my DS18B20:
first sensor 28D698D7400F8
second sensor 28FED6D64002B
third sensor 2880DC3C2009E

but how I put it in the code with $ ?