Index: dialin/common/hd_defs.py
===================================================================
diff -u -r1fd5bc0ed97d0d90223fa78ec195dd7636712c5b -rb31694e714c45e0678632ab11efbcdcf6dbf6e96
--- dialin/common/hd_defs.py	(.../hd_defs.py)	(revision 1fd5bc0ed97d0d90223fa78ec195dd7636712c5b)
+++ dialin/common/hd_defs.py	(.../hd_defs.py)	(revision b31694e714c45e0678632ab11efbcdcf6dbf6e96)
@@ -28,7 +28,17 @@
     MODE_POST = 7                                   # Post-Treatment mode
     NUM_OF_MODES = 8                                # Number of HD operation modes
 
+@unique
+class HDOpSubModes(DialinEnum):
+    SUBMODE_START = 0
+    SUBMODE_WAIT_FOR_TREATMENT = 1
+    SUBMODE_WAIT_FOR_DISINFECT = 2
+    SUBMODE_DG_FLUSH_IN_PROGRESS = 3
+    SUBMODE_DG_HEAT_DISINFECT_IN_PROGRESS = 4
+    SUBMODE_DG_CHEMICAL_DISINFECT_IN_PROGRESS = 5
+    NUM_OF_MODES = 6
 
+
 @unique
 class PreTreatmentSubModes(DialinEnum):
     HD_PRE_TREATMENT_START_STATE = 0
Index: dialin/ui/hd_simulator.py
===================================================================
diff -u -r0514a69831286e4727429f57e046f71e73e78110 -rb31694e714c45e0678632ab11efbcdcf6dbf6e96
--- dialin/ui/hd_simulator.py	(.../hd_simulator.py)	(revision 0514a69831286e4727429f57e046f71e73e78110)
+++ dialin/ui/hd_simulator.py	(.../hd_simulator.py)	(revision b31694e714c45e0678632ab11efbcdcf6dbf6e96)
@@ -1039,17 +1039,19 @@
                                            TXStates.SALINE_BOLUS_STATE_IDLE,
                                            TXStates.HEPARIN_STATE_OFF)
 
-    def cmd_set_hd_operation_mode_data(self, operation_mode):
+    def cmd_set_hd_operation_mode_data(self, operation_mode: int, operation_sub_mode: int) -> None:
         """
         The HD Operation Mode Data message setter/sender method
         | MSG  | CAN ID | Box | Type   | Ack | Src | Dst | Description            | #1:(U32)            |
         |:----:|:------:|:---:|:------:|:---:|:---:|:---:|:-----------:           |:--:                 |
         |0x2500| 0x040  | 7   | 1 Hz   | N   | HD  | All | HD Operation Mode Data | \ref Data::mOpMode  |
         :param operation_mode: (int) Operation Mode
-        :return: none
+        :param operation_sub_mode: (int) Operation Sub-Mode
+        :return: None
         """
 
         payload = integer_to_bytearray(operation_mode)
+        payload += integer_to_bytearray(operation_sub_mode)
 
         message = DenaliMessage.build_message(channel_id=DenaliChannels.hd_sync_broadcast_ch_id,
                                               message_id=MsgIds.MSG_ID_HD_OP_MODE.value,
Index: tests/peter/test_POST.py
===================================================================
diff -u -r33ca5c4128dec6677a0c8bd8e69e439521f6120a -rb31694e714c45e0678632ab11efbcdcf6dbf6e96
--- tests/peter/test_POST.py	(.../test_POST.py)	(revision 33ca5c4128dec6677a0c8bd8e69e439521f6120a)
+++ tests/peter/test_POST.py	(.../test_POST.py)	(revision b31694e714c45e0678632ab11efbcdcf6dbf6e96)
@@ -18,24 +18,22 @@
 sys.path.append("../../")
 from dialin import HDSimulator, DGSimulator
 from time import sleep
+from dialin.common import HDOpModes, HDOpSubModes
 
 SUCCESS = 1
 FAILURE = 0
 NUM_HD_TESTS = 8
 NUM_DG_TESTS = 6
 
-hd_sim = HDSimulator(log_level="DEBUG")
-dg_sim = DGSimulator(log_level="DEBUG")
+hd_sim = HDSimulator()
+dg_sim = DGSimulator()
 
-for test_num in range(NUM_HD_TESTS-1):
-    hd_sim.cmd_send_hd_post_single_result(SUCCESS, test_num=test_num)
-    sleep(1)
-hd_sim.cmd_send_hd_post_single_result(FAILURE, test_num=7)
-hd_sim.cmd_send_hd_post_final_result(FAILURE)
+for _ in range(40):
+    hd_sim.cmd_set_hd_operation_mode_data(HDOpModes.MODE_INIT.value, HDOpSubModes.SUBMODE_START.value)
+    sleep(0.25)
 
-for test_num in range(NUM_DG_TESTS-1):
-    dg_sim.cmd_send_dg_post_single_result(SUCCESS, test_num=test_num)
-    sleep(1)
-dg_sim.cmd_send_dg_post_single_result(FAILURE, test_num=5)
-dg_sim.cmd_send_dg_post_final_result(FAILURE)
+dg_sim.cmd_send_dg_post_final_result(SUCCESS)
+hd_sim.cmd_send_hd_post_final_result(SUCCESS)
 
+sleep(2)
+hd_sim.cmd_set_hd_operation_mode_data(HDOpModes.MODE_STAN.value, HDOpSubModes.SUBMODE_START.value)