Universal soldering controller

The intention was to build the most universal soldering controller I can think of. It can drive any low voltage (upto 24V) iron with thermocouple or resistive sensor, in series with the heater, or separate.

Here is a short list of features:
– power: 9-28V, AC or DC
– 2 separate heater control channels
– 2 independent sensor inputs
– current source on any sensor input 3uA – 12mA, wuth 2 bands (x1, x16) and 256 steps per band
– flexible differential amplifier input selection
– amplifier gain from 0 to 750 in 256 steps
– negative offset selection in 1024 steps
– resistive instrument identification (upto 625 different instruments can be identified by 2 resistors on the connector)
– polynomial floating point voltage/resistance to temperature calculation
– wave shaping to filter out the inductive peaks from series sensor signal
– PID control with power limit
– isolated USB port for firmware updates and live data
– 128×64 OLED display with rich user interface.

Tested so far with:
– HAKKO T12/T15 (series TC)
– HAKKO FX8801 (PTC)
– PACE TD100 (series TC)
– JBC C245 (series or separate TC)
– JBC C210 (series TC)
– JBC Microtweezers (2 separate heaters, each with series TC)
– WELLER WSP80 (PTC) (This iron was sent to me by a reader of the thread for a previous version of the controller. Thanks, Jaroslaw)
– ERSA RT80 (series PTC/heater resistance)
– various chinese cheap irons with separate TC

Here are the schematics, gerbers and software (3 May 2016):

The PC software is at very early stage of development and can only show live data and update the firmware for now.
There is some more work to be done with the firmware. I will also update this post from time to time with any additional info I find usefull. I will add iron connection diagrams and similar stuff soon.

For more detail: Universal soldering controller