diff --git a/_device_main.py b/_device_main.py
index 4fa229e..941b94b 100644
--- a/_device_main.py
+++ b/_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)
diff --git a/device_interaction.py b/device_interaction.py
index 6e2cb78..8c86edc 100644
--- a/device_interaction.py
+++ b/device_interaction.py
@@ -88,6 +88,9 @@ def request_state(prt):
 
 def send_control_parameters(prt, params):
     # Send control parameters
+    print("Sending PI coeffs (Q8): P1={} I1={} P2={} I2={}".format(
+        params['ProportionalCoeff_1'], params['IntegralCoeff_1'],
+        params['ProportionalCoeff_2'], params['IntegralCoeff_2']))
     hexstring = cmd.encode_Input(params)
     cmd.send_DECODE_ENABLE(prt,hexstring)
     time.sleep(WAIT_AFTER_SEND)
@@ -100,6 +103,9 @@ def send_control_parameters(prt, params):
 
 def send_task_command(prt, sending_param):
     # Send task command (TASK_ENABLE state in firmware)
+    print("Sending PI coeffs (Q8): P1={} I1={} P2={} I2={}".format(
+        sending_param['ProportionalCoeff_1'], sending_param['IntegralCoeff_1'],
+        sending_param['ProportionalCoeff_2'], sending_param['IntegralCoeff_2']))
     hexstring = cmd.create_TaskEnableCommand(sending_param)
     cmd.send_TASK_ENABLE(prt,hexstring)
     time.sleep(WAIT_AFTER_SEND)
diff --git a/gui.py b/gui.py
index 7b3772f..e9239b1 100644
--- a/gui.py
+++ b/gui.py
@@ -19,6 +19,11 @@ SET_MANUAL_MODE_TEXT = 'Ручной режим ввода'
 SET_TEXT_WIDTH = 34
 SET_INPUT_WIDTH = 5
 
+SET_KP_TEXT_1 = 'Коэфф. P регулятора лазера 1 (0-255):'
+SET_KI_TEXT_1 = 'Коэфф. I регулятора лазера 1 (0-255):'
+SET_KP_TEXT_2 = 'Коэфф. P регулятора лазера 2 (0-255):'
+SET_KI_TEXT_2 = 'Коэфф. I регулятора лазера 2 (0-255):'
+
 SET_MIN_TEMPERATURE_TEXT_1 = 'Минимальная температура лазера 1 (C):'
 SET_MAX_TEMPERATURE_TEXT_1 = 'Максимальная температура лазера 1 (C):'
 SET_DELTA_TEMPERATURE_TEXT_1 = 'Шаг дискретизации температуры лазера 1 (0.05-1 С):'
@@ -110,7 +115,13 @@ def setup_gui(params):
                         
                         [sg.Text(SET_CURRENT_TEXT_1, size=(SET_TEXT_WIDTH, 1)), sg.Push(),
                          sg.Input(params['Iset_1'], disabled_readonly_background_color="Gray", size=(SET_INPUT_WIDTH,1), key='-InputI1-', disabled = True)],
-                        
+
+                        [sg.Text(SET_KP_TEXT_1, size=(SET_TEXT_WIDTH, 1)), sg.Push(),
+                         sg.Input(params['ProportionalCoeff_1']/256, size=(SET_INPUT_WIDTH,1), key='-InputKp1-')],
+
+                        [sg.Text(SET_KI_TEXT_1, size=(SET_TEXT_WIDTH, 1)), sg.Push(),
+                         sg.Input(params['IntegralCoeff_1']/256, size=(SET_INPUT_WIDTH,1), key='-InputKi1-')],
+
                         [sg.HSeparator(pad=H_SEPARATOR_PAD)],
                         
                         [sg.Push(), sg.Text(READ_TEMPERATURE_TEXT+' 1: ', key='-TOUT_1-')],
@@ -129,9 +140,15 @@ def setup_gui(params):
     layout_input_col2 = [[sg.Text(SET_TEMPERATURE_TEXT_2, size=(SET_TEXT_WIDTH, 1)), sg.Push(),
                             sg.Input(params['Temp_2'], disabled_readonly_background_color="Gray", size=(SET_INPUT_WIDTH,1), key='-InputT2-', disabled = True)],
                         
-                        [sg.Text(SET_CURRENT_TEXT_2, size=(SET_TEXT_WIDTH, 1)), sg.Push(), 
+                        [sg.Text(SET_CURRENT_TEXT_2, size=(SET_TEXT_WIDTH, 1)), sg.Push(),
                             sg.Input(params['Iset_2'], disabled_readonly_background_color="Gray", size=(SET_INPUT_WIDTH,1), key='-InputI2-', disabled = True)],
-                        
+
+                        [sg.Text(SET_KP_TEXT_2, size=(SET_TEXT_WIDTH, 1)), sg.Push(),
+                            sg.Input(params['ProportionalCoeff_2']/256, size=(SET_INPUT_WIDTH,1), key='-InputKp2-')],
+
+                        [sg.Text(SET_KI_TEXT_2, size=(SET_TEXT_WIDTH, 1)), sg.Push(),
+                            sg.Input(params['IntegralCoeff_2']/256, size=(SET_INPUT_WIDTH,1), key='-InputKi2-')],
+
                         [sg.HSeparator(pad=H_SEPARATOR_PAD)],
                         
                         [sg.Push(), sg.Text(READ_TEMPERATURE_TEXT+' 2: ', key='-TOUT_2-')],