Доработка. Приём и отправка сообщений по протоколу modbus.

scripts/sch3.gd

@@ -1,13 +1,27 @@
 extends Node
 
+var cnt: int = 0
+var rw: bool = true
+
 func _ready():
     var unit_key = repsettings.get_unit_key('уарэп-щ3')
     var unit = repnetwork.units[unit_key]
     var timer = Timer.new()
     add_child(timer)
+    unit.connect('command_fail', Callable(self, 'on_command_fail'))
     timer.connect('timeout', Callable(self, 'on_timer').bind(unit))
     timer.start(1.0)
 
 
 func on_timer(unit):
-    unit.read_holdind(0x0000)
+    cnt +=1
+    if rw:
+        unit.write(0x0000, [cnt])
+    else:
+        unit.read_holdind(0x0000)
+    rw = not rw
+
+
+func on_command_fail(unit):
+    unit.cmd_state = unit.CmdState.DONE
+    print_debug('on_command_fail')