Add editable PI controller coefficient fields to GUI

_device_main.py

@@ -44,6 +44,15 @@ def get_float(values, strId):
         window['-StartCycle-'].update(disabled = True)
     return value
 
+def read_pi_coeff(values, key, params, param_key):
+    # PI coefficient is entered as a human value and stored as Q8 fixed-point
+    # (value * 256), clamped to the 16-bit range expected by the firmware.
+    # On a bad/empty field the previous stored value is kept and Start is disabled.
+    try:
+        params[param_key] = max(0, min(65535, int(float(values[key]) * 256)))
+    except (ValueError, TypeError):
+        window['-StartCycle-'].update(disabled = True)
+
 def shorten(i):
     return "{:.2f}".format(round(i, 2))
 
@@ -119,7 +128,13 @@ if __name__ == "__main__":
 
     while True:
         event, values = window.read(timeout=GUI_TIMEOUT_INTERVAL)
-    
+
+        if values:
+            read_pi_coeff(values, '-InputKp1-', params, 'ProportionalCoeff_1')
+            read_pi_coeff(values, '-InputKi1-', params, 'IntegralCoeff_1')
+            read_pi_coeff(values, '-InputKp2-', params, 'ProportionalCoeff_2')
+            read_pi_coeff(values, '-InputKi2-', params, 'IntegralCoeff_2')
+
         enable_manual_settings = window['-EnableManualSettings-'].get()
         if current_and_temperature_settings_available:
             window['-EnableT1-'].update(disabled = enable_manual_settings)