Please help me figure out differential temp controller

[SG09]

Below is a program I am trying to run to control the operation of my solar thermal heating system.· The intro describes how it might operate.· Thanks to the good people of this forum and the sample code from PH Anderson (vendor for the one-wire interface), I was able to actually measure and display the temperatures measured by the DS18S20s.· I am trying to write the code that actually compares the two temps and then takes action (haven't gotten to the actual relay control stuff yet).· The way I have the IF THENs written, the program seems to ignore the values of the two temps and simply writes the debug statement to the screen.· I tried looking for examples, but I am lost!· Please help, it will be cold soon.

Thanks!




' {$STAMP BS2}
' {$PBASIC 2.0 }
'This program measures the temperatures of the solar thermal panel and the storage tank.· When the panel is ten or more degrees warmer than the storage tank,
'a signal will be sent to start the circulating pump.· When the temperature of the panel cools to the temperature of the tank, a signal will be sent
'to stop the pump.· Controller will then continue to monitor·both temperatures.

··· BaudMode· CON· 84········· '9600 True
··· X VAR Word
··· Y VAR Word
··· degF1 VAR Word
··· degF2 VAR Word
··· SignBit VAR Byte
··· Whole VAR Byte
··· Fract VAR Byte
··· DIR7 = 0· ' serial input
··· DIR8 = 1· ' serial output
··· OUT8 = 0· ' be sure SerOut pin is stable at zero
··· 'Measure temperature on Channel 1 (Panel Temperature)
··· PAUSE 1000
DO
AGN:
··· SEROUT 8, BaudMode, 10, ["P0", "W0cc", "S044"]· 'perform temp meas
·········································· ' note strong pullup
··· PAUSE 1100······· ' wait for conversion to complete
··· SEROUT 8, BaudMode, 10, ["P0", "W0cc", "W0be"]·· ' send temperature data
··· SEROUT 8, BaudMode, 10, ["R0"]·· ' fetch data
··· SERIN 7, Baudmode, 1500, TimeOut, [DEC X.LOWBYTE]
··· PAUSE 100
··· SEROUT 8, BaudMode, 10, ["R0"]·· ' fetch data
··· SERIN 7, Baudmode, 1500, TimeOut, [DEC X.HIGHBYTE]
··· PAUSE 100
········· ' now do the calculations
····· x = x * 5·· ' multiplication works okay in twos complement
········ 'Now show degrees Fahrenheit
··· degF1 = x + 178 * 9 / 5
··· DEBUG REP "-"\degF1.BIT15, "Panel = ", DEC ABS degF1/10, ".", DEC1 ABS degF1, CR
··· PAUSE 2000 ' wait 2 secs
··· '-----------------------------------------------------------------------------------
··· 'Now measure temperature on Channel 2 (Tank Temperature)
··· SEROUT 8, BaudMode, 10, ["P1", "W1cc", "S144"]· 'perform temp meas
··· PAUSE 1100······· ' wait for conversion to complete
··· SEROUT 8, BaudMode, 10, ["P1", "W1cc", "W1be"]·· ' send temperature data
··· SEROUT 8, BaudMode, 10, ["R1"]·· ' fetch data
··· SERIN 7, Baudmode, 1500, TimeOut, [DEC X.LOWBYTE]
··· PAUSE 100
··· SEROUT 8, BaudMode, 10, ["R1"]·· ' fetch data
··· SERIN 7, Baudmode, 1500, TimeOut, [DEC X.HIGHBYTE]
··· PAUSE 100
···················· ' now do the calculations
····· x = x * 5·· ' multiplication works okay in twos complement
········ 'Now show degrees Fahrenheit
··· degF2 = x + 178 * 9 / 5
··· DEBUG REP "-"\degF2.BIT15, "Tank =· ", DEC ABS degF2/10, ".", DEC1 ABS degF2
··· PAUSE 2000 ' wait 2 secs
··· '_________________________________________________ ________________________________
··· 'Now compare the two values and turn pump ON if conditions are true
····· IF (degF1 >= (degF2 + 10)) THEN· StartPump:
··· StartPump:
··· DEBUG "Pump is ON", CR
····· IF (degF1 <= degF2) THEN StopPump:
···· StopPump:
··· DEBUG "Pump is OFF", CR

···· Timeout:
GOTO AGN:

[Franklin]

What does it write in the debug statements? Reduce your code to reading one sensor and writing the value to the debug screen. Once you get correct data add the second sensor and get the two values.

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- Stephen

[SG09]

I am able to get both values, it's just that I can't get·beyond there.· This is the output to the debug screen:


Panel = 71.6

Tank = 71.6Pump is ON

Pump is OFF



······· Panel = 71.6


Tank = 71.6Pump is ON

Pump is OFF······· This just repeats....

Although the temperature will change , I don't know how to write the program to do what I want.· I can change the IF THEN parameters and place my finger on the sensor to change the temp; it doesn't seem to affect the text that is displayed to the debug screen.

[stamptrol]

In the section where you make the comparison, you have no way of getting out if the temperature statement is false. It always goes to the startpump: label.

This is the logic you want, I think.

IF (degF1 >= (degF2 + 10)) THEN
goto StartPump:
elseif (degF1 <= degF2) THEN
goto StopPump:
endif
goto agn

StartPump:
DEBUG "Pump is ON", CR
high pumppin
goto agn

StopPump:
DEBUG "Pump is OFF", CR
low pumppin
goto agn

Cheers,

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Tom Sisk

http://www.siskconsult.com
·

[SG09]

elseif (degF1 <= (degF2 + 10)) THEN StopPump:

This gives the error "expected ':' or end of line

This is where I got stuck before. Thanks!

[stamptrol]

Make sure you're using PBASIC 2.5 ( click on "Directive" and choose the Stamp type you're using and PBasic 2.5). You may need to download the free upgrade of the software. You also have an open "DO" without the required closing "WHILE". Your code will run without it.

Note that my code snippet is using a different variation of the the IF-THEN command.

The code snippet runs on my machine.

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Tom Sisk

http://www.siskconsult.com
·

[Franklin]

Are you sure you want the : in the GOTO statement?


IF (degF1 >= (degF2 + 10)) THEN
goto StartPump:


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- Stephen

[stamptrol]

You're right...hazard of cut and paste!

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Tom Sisk

http://www.siskconsult.com
·

[SG09]

IF (degF1 >= (degF2 + 10)) THEN StartPump:
ELSEIF (degF1 <= (degF2 + 10) THEN StopPump
ENDIF
GOTO agn

Now I'm getting "ELSEIF must be preceeded by IF". I don't understand?

[stamptrol]

You're going to have to look at the the IF statement. It stops at THEN.
goto StartPump goes on the next line.

Look at the Helpfile for the IF statement and its two variations as was pointed out previously.

IF (degF1 >= (degF2 + 10)) THEN
goto StartPump
ELSEIF (degF1 <= (degF2 + 10) THEN
goto StopPump
ENDIF
GOTO agn

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Tom Sisk

http://www.siskconsult.com
·

[sam_sam_sam]

I have no way of testing this code for you

I cleaned up your code routines for you a little and it now·compiles

One ·Note· You have '·· {$PBASIC 2.0}·you should use ·'·· {$PBASIC 2.5}

Also you should when you have a small routine that repeats it self you have it as a sub routine

calculations:
········· ' now do the calculations
····· x = x * 5·· ' multiplication works okay in twos complement
········ 'Now show degrees Fahrenheit
··· degF1 = x + 178 * 9 / 5

··· PAUSE 2000 ' wait 2 secs
··· RETURN

I hope this helps


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··Thanks for any·http://forums.parallax.com/images/smilies/idea.gif·that you may have and all of your time finding them http://forums.parallax.com/images/smilies/smile.gif

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Sam

[SG09]

It works!!! Thanks for your patience, Tom. I was trying to make it more complex than it really was. The problem was that I was telling the program to proceed to the label (and then I had the label with a colon, followed by the instructions), instead of just immediately listing the instructions after the label.

I know I'm not explaining well. Thanks again.

Bill

[SG09]

Sam,

Thank you for doing this for me. Looks great all cleaned up and organized. I will load it and give it a test. Eventually, I would like to be able to log the data 24/7 for analysis and get my 12 yr old son to help with a VB interface. Sooo much more to learn and little time!

Bill

[sam_sam_sam]

Bill

It take time to get where you can write neat and· organized code

When I frist have a http://forums.parallax.com/images/smilies/idea.gif·my code look a mess and I have to take time to clean it up

Meaning: That small routine that are repeated are put in sub routines and·VAR ,CON, I/O· are put in there place

I am still learning how to write good working code

I hope this helps hang in there

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··Thanks for any·http://forums.parallax.com/images/smilies/idea.gif·that you may have and all of your time finding them http://forums.parallax.com/images/smilies/smile.gif

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Sam