Index: dialin/dg/drain.py
===================================================================
diff -u
--- dialin/dg/drain.py	(revision 0)
+++ dialin/dg/drain.py	(revision 5d78d2fee0667e97de44ea986b7353452e8c2230)
@@ -0,0 +1,144 @@
+###########################################################################
+#
+# Copyright (c) 2022-2023 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    gen_idle.py
+#
+# @author  (last)      Michael Garthwaite
+# @date    (last)      08-Aug-2023
+# @author  (original)  Michael Garthwaite
+# @date    (original)  08-Aug-2022
+#
+############################################################################
+import struct
+from logging import Logger
+
+from .constants import RESET, NO_RESET
+from ..common.msg_defs import MsgIds, MsgFieldPositions
+from ..protocols.CAN import DenaliMessage, DenaliChannels
+from ..utils.base import AbstractSubSystem, publish
+from ..utils.checks import check_broadcast_interval_override_ms
+from ..utils.conversions import integer_to_bytearray
+
+
+class Drain(AbstractSubSystem):
+    """
+    Dialysate Generation (DG) interface for drain op mode related commands.
+    """
+
+    def __init__(self, can_interface, logger: Logger):
+        """
+        Initialize CAN interface and logger
+        @param can_interface: Denali CAN Messenger object
+        @param: logger: (Logger) object
+        """
+
+        super().__init__()
+
+        self.can_interface = can_interface
+        self.logger = logger
+        # The current bad fill sub-state
+        self.bad_fill_state = 0
+        self.bad_fill_signal = 0
+        self.drain_mode_state = 0
+
+        if self.can_interface is not None:
+            channel_id = DenaliChannels.dg_sync_broadcast_ch_id
+            msg_id = MsgIds.MSG_ID_DG_GEN_IDLE_DATA.value
+            self.can_interface.register_receiving_publication_function(channel_id, msg_id,
+                                                                       self._handler_gen_idle_sync)
+
+    def get_bad_fill_sub_state(self):
+        """
+        Gets current bad fill sub-state
+
+        @param: none
+        @return: The current bad fill sub-state
+        """
+        return self.bad_fill_state
+
+    def get_gen_idle_sub_state(self):
+        """
+        Gets current gen idle sub-state
+
+        @param: none
+        @return: The current gen idle sub state
+        """
+        return self.gen_idle_state
+
+    def get_gen_idle_target_fill(self):
+        """
+        Gets current gen idle target fill
+
+        @param: none
+        @return: The current bad fill sub-state
+        """
+        return self.target_fill_volume_ml
+
+    def get_bad_fill_signal(self):
+        """
+        Gets current bad fill signal
+
+        @param: none
+        @return: The current bad fill signal
+        """
+        return self.bad_fill_signal
+
+    @publish(["dg_gen_idle_data_timestamp","gen_idle_state", "target_fill_volume_ml", "bad_fill_signal", "bad_fill_state"])
+    def _handler_gen_idle_sync(self, message, timestamp=0.0):
+        """
+        Handles published gen idle sub-states message.
+
+        @param message: published gen idle sub-states message
+        @return: none
+        """
+
+        self.gen_idle_state = struct.unpack('<I', bytearray(
+            message['message'][MsgFieldPositions.START_POS_FIELD_1:MsgFieldPositions.END_POS_FIELD_1]))[0]
+        self.target_fill_volume_ml = struct.unpack('<I', bytearray(
+            message['message'][MsgFieldPositions.START_POS_FIELD_2:MsgFieldPositions.END_POS_FIELD_2]))[0]
+        self.bad_fill_signal = struct.unpack('<I', bytearray(
+            message['message'][MsgFieldPositions.START_POS_FIELD_3:MsgFieldPositions.END_POS_FIELD_3]))[0]
+        self.bad_fill_state = struct.unpack('<I', bytearray(
+            message['message'][MsgFieldPositions.START_POS_FIELD_4:MsgFieldPositions.END_POS_FIELD_4]))[0]
+
+        self.dg_gen_idle_data_timestamp = timestamp
+
+    def cmd_bad_fill_substates_data_broadcast_interval_override(self, ms: int, reset: int = NO_RESET) -> int:
+        """
+        Constructs and sends the fill mode data broadcast interval override command
+        Constraints:
+            Must be logged into DG.
+            Given interval must be non-zero and a multiple of the DG general task interval (50 ms).
+
+        @param ms:  integer - interval (in ms) to override with
+        @param reset:  integer - 1 to reset a previous override, 0 to override
+        @return: 1 if successful, zero otherwise
+        """
+
+        if not check_broadcast_interval_override_ms(ms):
+            return False
+
+        reset_byte_array = integer_to_bytearray(reset)
+        ms_byte_array = integer_to_bytearray(ms)
+        payload = reset_byte_array + ms_byte_array
+
+        message = DenaliMessage.build_message(channel_id=DenaliChannels.dialin_to_dg_ch_id,
+                                              message_id=MsgIds.MSG_ID_DG_GEN_IDLE_PUBLISH_INTERVAL_OVERRIDE.value,
+                                              payload=payload)
+
+        self.logger.debug("override gen idle sub-states data broadcast interval")
+
+        # Send message
+        received_message = self.can_interface.send(message)
+
+        # If there is content...
+        if received_message is not None:
+            # response payload is OK or not OK
+            return received_message['message'][DenaliMessage.PAYLOAD_START_INDEX]
+        else:
+            self.logger.error("Timeout!!!!")
+            return False