Index: dialin/dg/watchdog.py
===================================================================
diff -u
--- dialin/dg/watchdog.py	(revision 0)
+++ dialin/dg/watchdog.py	(revision 5b2d913869600b7f9846eb4c64267538173686cf)
@@ -0,0 +1,81 @@
+###########################################################################
+#
+# Copyright (c) 2020-2023 Diality Inc. - All Rights Reserved.
+#
+# THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
+# WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
+#
+# @file    watchdog.py
+#
+# @author  (last)      Michael Garthwaite
+# @date    (last)      15-Aug-2023
+# @author  (original)  Michael Garthwaite
+# @date    (original)  15-Aug-2023
+#
+############################################################################
+from logging import Logger
+
+from .constants import RESET, NO_RESET
+from ..common import MsgIds
+from ..protocols.CAN import DenaliMessage, DenaliChannels
+from ..utils.base import AbstractSubSystem
+from ..utils.conversions import integer_to_bytearray
+
+
+class DGWatchdog(AbstractSubSystem):
+    """
+    Dialysate Generator (DG) Dialin API sub-class for watchdog related commands.
+    """
+
+    def __init__(self, can_interface, logger: Logger):
+        """
+
+        @param can_interface: the Denali CAN interface object
+        """
+
+        super().__init__()
+        self.can_interface = can_interface
+        self.logger = logger
+
+    def cmd_watchdog_task_check_in_override(self, state: int, task: int, reset: int = NO_RESET) -> int:
+        """
+        Constructs and sends the watchdog task check-in override command
+        Constraints:
+            Must be logged into DG.
+            Given task must be valid.
+            Given state must be a 0 or 1.
+
+        @param state:  integer - 1 for task checked in, 0 for task not checked in
+        @param task:  integer - ID of task to override
+        @param reset:  integer - 1 to reset a previous override, 0 to override
+        @return: 1 if successful, zero otherwise
+        """
+
+        rst = integer_to_bytearray(reset)
+        sta = integer_to_bytearray(state)
+        tsk = integer_to_bytearray(task)
+        payload = rst + sta + tsk
+
+        message = DenaliMessage.build_message(channel_id=DenaliChannels.dialin_to_dg_ch_id,
+                                              message_id=MsgIds.MSG_ID_DG_WATCHDOG_TASK_CHECKIN_OVERRIDE.value,
+                                              payload=payload)
+
+        self.logger.debug("override DG watchdog task check-in state")
+
+        # Send message
+        received_message = self.can_interface.send(message)
+
+        # If there is content...
+        if received_message is not None:
+            # self.logger.debug(received_message)
+            if reset == RESET:
+                str_res = "reset back to normal"
+            else:
+                str_res = ("checked in" if state != 0 else "not checked in")
+            self.logger.debug("watchdog task check-in overridden to " + str_res + ":" +
+                              str(received_message['message'][DenaliMessage.PAYLOAD_START_INDEX]))
+            # response payload is OK or not OK
+            return received_message['message'][DenaliMessage.PAYLOAD_START_INDEX]
+        else:
+            self.logger.debug("Timeout!!!!")
+            return False