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temp control with 8051
Moderators: Ajay Bhargav, Arun Kumar V, pdi33, Shailesh NAYAK, ۞ TPS ۞, shyam, sashijoseph, ExperimenterUK, DavesGarage
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memphis
Wed Jun 17 2009, 11:52AM
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temp should be 20C+/- 1C
temp sensors are connected via INT0 and INT1 and giving HOT and COLD signals

hints:
if T>21 then HOT=0
if t<19 then COLD=0

if P1.7=1 then heater should be set ON
if P1.7=0 then heater should be set OFF

i need very small piece of assembly code. or at least code sketch

many thanks in advance..
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DavesGarage
Wed Jun 17 2009, 01:16PM

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You'll need to be a little more specific.

You said:
temp sensors are connected via INT0 and INT1 and giving HOT and COLD signals

does this mean that you have a temperature sensor connected to INT0 that will go high when the target temperature is too hot, but otherwise be low? And does this mean that you have another temperature sensor connected to INT1 that will go high when the target temperature is too cold, but otherwise be low?

it is unclear what you mean...

Conversely, you said:
if P1.7=1 then heater should be set ON
if P1.7=0 then heater should be set OFF

this also sounds like you have a temperature sensor connected to P1.7

very confusing, sorry...

-Dave
"Basic research is what I am doing when I don't know what I am doing"
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Kiran V Sutar
Wed Jun 17 2009, 11:11PM
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HI,
Can you tell me, what type of sensor have you connected to the INT0, INT1 of CPU?

I don't know any such sensor that can be connected directly to 8051 pins..!!!

You mentioned Heater. Now to which pin of the CPU, have you connected the heater?

You mentioned:
if T>21 then HOT=0
What should happen if T<21 ?

You mentioned:
if t<19 then COLD=0
What should happen if T>19

What is the condition of HOT and COLD when Temp=20?

How is the heater related to HOT?

If you are looking for just ON-OFF type control, you will never, ever achieve + 1 Deg.C accuracy.



[ Edited Wed Jun 17 2009, 11:12PM ]
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Ajay Bhargav
Thu Jun 18 2009, 03:43AM
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memphis, seems like you are using a Thermostat sensor? is it?

it would be better to post the circuit so we can help you better.

[Topic moved to 8051 Discussion forum]

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