diff --git a/debye_bec/services/NIDAQ_writer/NIDAQ_writer.py b/debye_bec/services/NIDAQ_writer/NIDAQ_writer.py
index 3f62c43..b536032 100644
--- a/debye_bec/services/NIDAQ_writer/NIDAQ_writer.py
+++ b/debye_bec/services/NIDAQ_writer/NIDAQ_writer.py
@@ -159,7 +159,7 @@ class NIDAQWriterService(BECService):
         signals = {}
 
         for key in msgs[0].content["signals"]:
-            signals[key] = np.concatenate([msg.content["signals"][key] for msg in msgs])
+            signals[key] = np.concatenate([msg.content["signals"][key]["value"] for msg in msgs])
 
         # write data to queue
         self.queue.put(signals)
diff --git a/tests/tests_services/test_file_writer_service.py b/tests/tests_services/test_file_writer_service.py
index 9b6ff81..7a8e830 100644
--- a/tests/tests_services/test_file_writer_service.py
+++ b/tests/tests_services/test_file_writer_service.py
@@ -95,9 +95,14 @@ def test_nidaq_handle_scan_status(nidaq, scan_status):
 
 def test_nidaq_handle_ni_data(nidaq):
     data = [
-        messages.DeviceMessage(signals={"signal1": list(range(10)), "signal2": list(range(10))}),
         messages.DeviceMessage(
-            signals={"signal1": list(range(10, 20)), "signal2": list(range(10, 20))}
+            signals={"signal1": {"value": list(range(10))}, "signal2": {"value": list(range(10))}}
+        ),
+        messages.DeviceMessage(
+            signals={
+                "signal1": {"value": list(range(10, 20))},
+                "signal2": {"value": list(range(10, 20))},
+            }
         ),
     ]