diff --git a/b_asic/core_operations.py b/b_asic/core_operations.py
index c822fe8f4843c26f5dfabc33a48f3cbe92d74eef..6459948ca58a879a7853ea2e5846509d567ee79e 100644
--- a/b_asic/core_operations.py
+++ b/b_asic/core_operations.py
@@ -22,7 +22,7 @@ class Constant(AbstractOperation):
 
     def __init__(self, value: Number = 0, name: Name = ""):
         """Construct a Constant operation with the given value."""
-        super().__init__(input_count=0, output_count=1, name=name)
+        super().__init__(input_count=0, output_count=1, name=name, latency_offsets={'out0' : 0})
         self.set_param("value", value)
 
     @classmethod
diff --git a/b_asic/schema.py b/b_asic/schema.py
index 044df1ca1976a95db0e6e6836b9fab599bde7194..523137741d03f812c6ac14b317526b276c099d98 100644
--- a/b_asic/schema.py
+++ b/b_asic/schema.py
@@ -174,7 +174,10 @@ class Schema:
                     self._start_times[op.graph_id] = op_start_time
         for output in self._sfg.find_by_type_name(Output.type_name()):
             source_port = output.inputs[0].signals[0].source
-            self._start_times[output.graph_id] = self._start_times[source_port.operation.graph_id] + source_port.latency_offset
+            if source_port.operation.graph_id in non_schedulable_ops:
+                self._start_times[output.graph_id] = 0
+            else:
+                self._start_times[output.graph_id] = self._start_times[source_port.operation.graph_id] + source_port.latency_offset
         self._remove_delays()
 
     def plot_schedule(self) -> None:
diff --git a/test/test_schema.py b/test/test_schema.py
index 425fc02555ffee9569f0701ad16f0f7bde3362de..40f2cc3e50c907a0a5956f320309822e8dd39a2d 100644
--- a/test/test_schema.py
+++ b/test/test_schema.py
@@ -12,7 +12,7 @@ class TestInit:
 
         schema = Schema(sfg_simple_filter)
 
-        assert schema._start_times == {"add1": 4, "cmul1": 0}
+        assert schema._start_times == {"in1": 0, "add1": 4, "cmul1": 0, "out1": 0}
 
     def test_complicated_single_outputs_normal_latency(self, precedence_sfg_delays):
         precedence_sfg_delays.set_latency_of_type(Addition.type_name(), 4)
@@ -28,8 +28,8 @@ class TestInit:
             op_name = precedence_sfg_delays.find_by_id(op_id).name
             start_times_names[op_name] = start_time
 
-        assert start_times_names == {"C0": 0, "B1": 0, "B2": 0, "ADD2": 3, "ADD1": 7, "Q1": 11,
-                                     "A0": 14, "A1": 0, "A2": 0, "ADD3": 3, "ADD4": 17}
+        assert start_times_names == {"IN1": 0, "C0": 0, "B1": 0, "B2": 0, "ADD2": 3, "ADD1": 7, "Q1": 11,
+                                     "A0": 14, "A1": 0, "A2": 0, "ADD3": 3, "ADD4": 17, "OUT1": 21}
 
     def test_complicated_single_outputs_complex_latencies(self, precedence_sfg_delays):
         precedence_sfg_delays.set_latency_offsets_of_type(ConstantMultiplication.type_name(), {'in0': 3, 'out0': 5})
@@ -53,8 +53,8 @@ class TestInit:
             op_name = precedence_sfg_delays.find_by_id(op_id).name
             start_times_names[op_name] = start_time
 
-        assert start_times_names == {'C0': 0, 'B1': 0, 'B2': 0, 'ADD2': 3, 'ADD1': 5, 'Q1': 6, 'A0': 12,
-                                     'A1': 0, 'A2': 0, 'ADD3': 3, 'ADD4': 8}
+        assert start_times_names == {'IN1': 0, 'C0': 0, 'B1': 0, 'B2': 0, 'ADD2': 3, 'ADD1': 5, 'Q1': 6, 'A0': 12,
+                                     'A1': 0, 'A2': 0, 'ADD3': 3, 'ADD4': 8, 'OUT1': 17}
 
     def test_independent_sfg(self, sfg_two_inputs_two_outputs_independent_with_cmul):
         schema = Schema(sfg_two_inputs_two_outputs_independent_with_cmul, scheduling_alg="ASAP")
@@ -64,7 +64,8 @@ class TestInit:
             op_name = sfg_two_inputs_two_outputs_independent_with_cmul.find_by_id(op_id).name
             start_times_names[op_name] = start_time
 
-        assert start_times_names == {'CMUL1': 0, 'CMUL2': 5, "ADD1": 0, "CMUL3": 7}
+        assert start_times_names == {'C1': 0, 'IN1': 0, 'IN2': 0, 'CMUL1': 0, 'CMUL2': 5,
+                                     "ADD1": 0, "CMUL3": 7, 'OUT1': 9, 'OUT2': 10}
 
     def test_slack_normal_latency(self, precedence_sfg_delays):
         precedence_sfg_delays.set_latency_of_type(Addition.type_name(), 1)