(41) Brewing Calculations

[Dieter]

(12-28-2017 04:38 AM)Craig Bladow Wrote:  "MIX" calculates the amount of water for each of two temperatures to mix together to achieve a target volume and final temperature. Since brewing involves heating water it is often the case that one has heated the water too much and needs to cool it down to a specific temperature.

Looking at your program I remember a similar application in the photo lab: you have x milliliters of cold developer and want to dilute it with y milliliters of warm water to get a certain amount of working solution at a defined temperature.

Example: you have 100 ml of developer stock solution at 18 °C, and you want to dilute it 1:3 to get 400 ml at 20 °C. So you add 300 ml of 20,7 °C warm water.

What about a program that can handle either case? Or even any possible case? But this doesn't look trivial to me. ;-)

Finally, here is a text version of your program. I have taken the liberty of adding question marks at the prompts, omitting R04 (which is not required) and saving a line in the final calculation steps. I hope this is OK.

Code:

LBL "MIX"
"QTY TOTAL?"
PROMPT
STO 01
"TEMP HOT?"
PROMPT
STO 02
"TEMP COLD?"
PROMPT
STO 03
"TEMP FINAL?"
PROMPT
RCL 02
-
RCL 01
*
RCL 03
RCL 02
-
/
RCL 01
X<>Y
-
LASTX
"QTY HOT "
FIX 2
ARCL X
AVIEW
STOP
"QTY CLD "
ARCL Y
FIX 4
AVIEW
END

Edit: saved another step during the calculation.

Dieter