How to swap a variable?

[mark_s]

Hello,

Not sure if this will help you. The receiving variable is always on the left side

In this statement you are moving the contents of temp into Block_temp

Block_temp = temp

The way I read your question you wanted to store or move the contents of Block_temp into
temp?

temp = Block_temp

Regards
Mark

[jessey]

In this statement you are moving the contents of temp into Block_temp - Block_temp = temp

Hi Mark,

Yes that's correct, I want to move the contents of temp into Radiator_temp on the first pass in the mainloop so I can see the temperature on the first line of my Lcd then on the second pass I change the Sensor_Select to be the Block_Sensor and then want to load temp into Block_temp so I can see it on the second line of the Lcd. I've tried many different combinations and just can't seem to get that to work. It does work and display properly if I mix it up like my code shows above, but it's a puzzler for me and I can't figure why that works and if it'll be reliable.

Thanks
jessey

[mark_s]

Hi Jessey,

I noticed in your 1st subroutine "Select_A_Sensor_To_Read:" you are swapping your variables before the gosub to "Check_Temperature:" . What happens if you read the temperature first
right before the swap statement. The last sensor reading will now be in the temp variable. It can now be stored in Radiator_Temp or Block_temp. The way you have it now it reads the temperature to temp and exits the subroutine.

Try this
Add a new variable Old_temp

If I = 0 Then''''''''''''''''''''

Sensor_Select = Radiator_Sensor' This is a little convoluted to say the
GOSUB Check_Temperature ' it should work then the program switches
SWAP Old_temp, Radiator_temp ' least but it works, how and why I have no
Radiator_temp = temp ' idea. If I uncomment the commented out code


Endif ' sensors around i.e. instead of reading the
' Radiator_Sensor on pin 15 it then reads
If I = 1 Then ' the sensor on 33 even though it's declared
Sensor_Select = Block_Sensor ' on pin 15 and vice versa for the
GOSUB Check_Temperature ' it should work then the program switches
SWAP Old_temp, Block_temp ' DS1820 Block_Sensor. So it switches the
Block_temp = temp ' two sensors, very confusing! It must be in


Endif
Return''''''''''''''''''''''''''''''

[jessey]

What happens if you read the temperature first right before the swap statement. The last sensor reading will now be in the temp variable. It can now be stored in Radiator_Temp or Block_temp. The way you have it now it reads the temperature to temp and exits the subroutine.

Thanks Mark,

That's all it took, I changed it like you suggested and it works perfectly now. Thanks for your help I really appreciate it.

Thanks Again
jessey

   If I = 0 Then                 
    Sensor_Select = Radiator_Sensor   
    GOSUB Check_Temperature 
    Radiator_temp = temp  
   Endif    
 
   If I = 1 Then 
    Sensor_Select = Block_Sensor 
    GOSUB Check_Temperature
    Block_temp = temp 
   Endif

[mark_s]

Jessey,
Glad to hear it's working!

How are you attaching or making contact with the DS1820's to your engine? I have a
generator that I would like to experiment with a temp read out and overheat cut off.

Thanks Mark