diff --git a/schunk_egu_egk_gripper_dummy/doc/plc_control_double_word.png b/schunk_egu_egk_gripper_dummy/doc/plc_control_double_word.png
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diff --git a/schunk_egu_egk_gripper_dummy/doc/plc_data_exchange.png b/schunk_egu_egk_gripper_dummy/doc/plc_data_exchange.png
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diff --git a/schunk_egu_egk_gripper_dummy/doc/plc_input_data_frame.png b/schunk_egu_egk_gripper_dummy/doc/plc_input_data_frame.png
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diff --git a/schunk_egu_egk_gripper_dummy/doc/plc_output_data_frame.png b/schunk_egu_egk_gripper_dummy/doc/plc_output_data_frame.png
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diff --git a/schunk_egu_egk_gripper_dummy/doc/plc_status_double_word.png b/schunk_egu_egk_gripper_dummy/doc/plc_status_double_word.png
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diff --git a/schunk_egu_egk_gripper_dummy/src/dummy.py b/schunk_egu_egk_gripper_dummy/src/dummy.py
index 42216d6..4e451cc 100644
--- a/schunk_egu_egk_gripper_dummy/src/dummy.py
+++ b/schunk_egu_egk_gripper_dummy/src/dummy.py
@@ -13,6 +13,8 @@ def __init__(self):
         self.enum = None
         self.metadata = None
         self.data = None
+        self.plc_input = "0x0040"
+        self.plc_output = "0x0048"
 
         enum_config = os.path.join(
             Path(__file__).resolve().parents[1], "config/enum.json"
@@ -30,6 +32,9 @@ def __init__(self):
         with open(data_config, "r") as f:
             self.data = json.load(f)
 
+        self.plc_input_buffer = bytearray(bytes.fromhex(self.data[self.plc_input][0]))
+        self.plc_output_buffer = bytearray(bytes.fromhex(self.data[self.plc_output][0]))
+
     def start(self) -> None:
         if self.running:
             return
@@ -83,6 +88,16 @@ def get_data(self, query: dict[str, str]) -> list:
                 return result
             if inst not in self.data:
                 return result
+            if inst == self.plc_input:
+                return self.get_plc_input()
+            if inst == self.plc_output:
+                return self.get_plc_output()
             return self.data[inst]
         else:
             return []
+
+    def get_plc_input(self):
+        return [self.plc_input_buffer.hex().upper()]
+
+    def get_plc_output(self):
+        return [self.plc_output_buffer.hex().upper()]
diff --git a/schunk_egu_egk_gripper_dummy/tests/test_plc_communication.py b/schunk_egu_egk_gripper_dummy/tests/test_plc_communication.py
new file mode 100644
index 0000000..cfd9c73
--- /dev/null
+++ b/schunk_egu_egk_gripper_dummy/tests/test_plc_communication.py
@@ -0,0 +1,48 @@
+from src.dummy import Dummy
+import pytest
+
+# [1]: https://stb.cloud.schunk.com/media/IM0046706.PDF
+
+
+def test_dummy_initializes_plc_data_buffers():
+    dummy = Dummy()
+    assert dummy.data[dummy.plc_input][0] == dummy.plc_input_buffer.hex().upper()
+    assert dummy.data[dummy.plc_output][0] == dummy.plc_output_buffer.hex().upper()
+
+
+def test_dummy_returns_plc_data():
+    dummy = Dummy()
+    assert dummy.data[dummy.plc_input] == dummy.get_plc_input()
+    assert dummy.data[dummy.plc_output] == dummy.get_plc_output()
+
+
+# See p. 24 in
+# Booting and establishing operational readiness [1]
+
+
+@pytest.mark.skip()
+def test_dummy_starts_in_error_state():
+    dummy = Dummy()
+    query = {"inst": dummy.plc_input, "count": 1}
+    data = dummy.get_data(query)[0]
+    assert data[0:2] == "80"
+    assert data[30:] == "D9"  # ERR_FAST_STOP
+
+
+@pytest.mark.skip()
+def test_dummy_is_ready_after_acknowledge():
+    dummy = Dummy()
+    control_double_word = "04000000"
+    set_position = "00000000"
+    set_speed = "00000000"
+    gripping_force = "00000000"
+    command = {
+        "inst": dummy.plc_output,
+        "value": control_double_word + set_position + set_speed + gripping_force,
+    }
+    dummy.post(command)
+
+    query = {"inst": dummy.plc_input, "count": 1}
+    data = dummy.get_data(query)[0]
+    assert data[0:2] == "11"
+    assert data[30:] == "00"  # ERR_NONE