diff --git a/src/toolbox_scs/constants.py b/src/toolbox_scs/constants.py
index 4bc7f975ea17b53ba8058ff5d00614d9f135d780..64b2180adf4d75afec2ac3145ac743ef6d363f90 100644
--- a/src/toolbox_scs/constants.py
+++ b/src/toolbox_scs/constants.py
@@ -378,6 +378,9 @@ mnemonics = {
     "Vertical_FDM": ({'source': 'SCS_CDIFFT_LDM/CAM/CAMERA1A:daqOutput',
                       'key': 'data.image.pixels',
                       'dim': ['vfdm_y', 'vfdm_x']},),
+    "Horizontal_FDM": ({'source': 'SCS_CDIFFT_LDM/CAM/CAMERA2A:daqOutput',
+                      'key': 'data.image.pixels',
+                      'dim': ['hfdm_y', 'hfdm_x']},),
     "LLC_webcam2": ({'source': 'SCS_CDILLC_VAC/CAM/WEBCAMERA2:daqOutput',
                      'key': 'data.image.pixels',
                      'dim': ['llc2_y', 'llc2_x']},),