Thread subject: Homeroasters - Home Roasting Coffee Community :: How to computer control Diedrich?
Posted by freddofrog on 12/08/2016 11:45 PM
#1
Hi all
I have access to a small gas Diedrich and wondering what is involved in making it computer controlled, ie Artisan automatically adjusts the gas flow based on bean temp.
I have already done this to my Behmor but Behmor is electric not gas.
Thoughts?
ff
Posted by btreichel on 12/09/2016 4:01 PM
#2
I've been thinking about a stepper motor attached to a gas valve controlled via an Arduino.
Posted by BenKeith on 12/09/2016 4:14 PM
#3
I think if you do a search, not too long back, someone posted a whole bunch of info using a TC4 and it's PWM to control a gas valve and the gas valve they used.
I think AllenB was fairly involved with it and he may have some good info on it.
Posted by oldgearhead on 12/10/2016 10:00 AM
#4
Yes an Allen Bradley PLC (pun intended) is the way I would go. Probably a used SLC504 unless I wanted to network it. Use an analog gas valve, 4-20 ma I/O, and a few digital circuits as needed...you will have a bunch of PID loops to choose from and the powerful "scale with parameters" instruction...hint - write your own PI control.
Edited by oldgearhead on 12/10/2016 10:09 AM
Posted by freddofrog on 12/13/2016 2:53 AM
#5
Yeah, I saw threads on controlling a gas value using PWM but I'm not sold on the concept. PWM for electric heaters I get but I would have thought gas valves need a proportional control like a servo motor.
I'll have a look again and see.