diff --git a/TimeBaseAOMDriver/labscript_devices.py b/TimeBaseAOMDriver/labscript_devices.py
index 505ce559f55c05b3e22752c3aaf1f7289324e5fd..72878506587e35826041692c860ccf63642de3ba 100644
--- a/TimeBaseAOMDriver/labscript_devices.py
+++ b/TimeBaseAOMDriver/labscript_devices.py
@@ -71,7 +71,8 @@ class TimeBaseAOM(Device):
         """
         if value not in self.parent_device.FM_deviations:
             raise LabscriptError(f"FM devivation of {self.name} is none of the allowed values.")
-        self.FM_deviation.constant(value)
+        set_value = int(np.round(np.log2(value/3200)))
+        self.FM_deviation.constant(set_value)