In order for the PID to work its magic, various parameters must be set on the controller itself. Fortunately, the PID controller takes care of the hard parts through a process called “autotuning”; through trial and error, the PID determines its own optimum settings necessary to hold the boiler at the desired setpoint. There are a few parameters, however, which need to be set by hand.
Make the following settings by hand. There are about 50 parameters that can be set manually; I only changed 5.
1. Primary Menu: Press and hold SEL key for 3 seconds. The only item of interest on the primary menu is autotune, which is discussed in the autotuning section below.
2. Secondary Menu: Press and hold SEL key for 7 seconds.
TC (cycle time): I have mine set to 1.
P-n2 (input type): Make sure this is set to 2 for type J thermocouple or 3 for type K.
P-dP (decimal point resolution): Set this to 1 to display temps in one-tenth degree increments.
3. Factory Presets Menu: Press and hold SEL for 9 seconds.
P-dF (input filter constant): This setting filters out quick changes in thermocouple readings and slows down PID responses, which is a bad thing for our application. I have mine set to 0.
FUZY (fuzzy logic): Helps eliminate overshoot. Set to On.
Autotuning is the process where the PID controller determines how output to the heating element affects boiler temperature. After autotuning, the PID sets its own proportional, integral, and derivative parameters so you don’t have to worry about it.
Turn on Silvia and the PID and let her warm up for, say, an hour.
Run some water through the portafilter or steam wand to lower the boiler temp.
Press the SEL key for 3 seconds, and then the down arrow key until AT (looks like A7) appears on the PID display.
Press the SEL key once to select autotuning.
Press the UP key once. The PID should display 1. The autotune LED on the PID will start to blink.
Wait a while (about 7 minutes in my experience). When autotuning is complete, the PID will return to the current temperature display.
That’s all there is to it. Silvia is ready to go.
The modifications described on these pages reflect the author’s own experience and are not intended to serve as a guide or instructions for others. These modifications involve tampering with high-wattage electrical circuits in a wet environment, which could result in electric shock, burns, other serious personal injury, or death, as well as fire, explosion, and other property damage. The author is not an electrician and the fact that his modifications were successful was purely a matter of luck. The author and/or MAKE is not responsible for injury or damage to or caused by anyone foolish enough to follow his example. Before you tinker with an espresso machine or any home appliance, make sure you know what you are doing or get help from someone who does. Modifying Silvia voids any warranty provided by the manufacturer and/or retailer.
John F. Murphy is a government lawyer in Fort Worth, Texas, who relies on espresso to fuel him through the work-a-day drudgery.