In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Dunnsept wrote:

I am getting started on my project (finally).
I am going to use an SX to control my coffee roaster. should be fairly simple. My coffee roaster is actually a hot-air popcorn popper.

I will use the SX to control the heater element while the fan is allowed to just run.

OK, so I have a basic flow chart and times & temps and I started putting together a skeleton bit of code (I'm waiting on the MAX6675 thermocouple amp)

soooo,.....I'm trying to decide if I want to use interrupts on this or not, and if so, which portion to put in the ISR.

 

my first thought is to put the 'measure the temp' portion in along with the timing.. but I'm not sure if it will really matter one way or another..

basic run is as follows:

 

energize heater, until temp = 350

hold 3 mins

raise temp to 410

hold 2 mins

raise temp to 440

hold 1.5 mins or until "operator" hits the "stop" button to end cycle early

 

thoughts? I have a dallas 1602 RTCC/elapsed time if I need it. I dont need any really fancy stuff to begin, meaning times and temps actually dont have to be really exact since each batch of beans will be different anyway. One of the biggest problems is trying to measure the beans' temperature ( coffee beans, not HITT beans) instead of measuring the air that is flowing thru the 'roaster'. generally the air temp is measured as it exits the chamber just above the surface of the beans and this is accepted practice and is about the best you can do considering that the beans are moving around like crazy. I'll be using thermocouple & the max6675 for this (provided I dont fry the 6675 SOIC trying to solder it in place... matter of fact, maybe I'd better order a couple extra)

so... just in a plain ol loop with delays in it? 

ISR for "polling" the max6675 as things move along 

ISR polling temp AND tracking time either internally or thru the 1602?

 

thanks

Paul...

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