diff --git a/python/lsst/obs/base/instrument_tests.py b/python/lsst/obs/base/instrument_tests.py
index ea65c03b..62778453 100644
--- a/python/lsst/obs/base/instrument_tests.py
+++ b/python/lsst/obs/base/instrument_tests.py
@@ -148,7 +148,7 @@ def register(self, registry, update=False):
                 registry.syncDimensionData(
                     "detector",
                     dict(
-                        dataId,
+                        instrument=self.getName(),
                         id=d,
                         full_name=f"RXX_S0{d}",
                     ),