diff --git a/src/modules/motion.h b/src/modules/motion.h
index 2c0b311..2cc67d8 100644
--- a/src/modules/motion.h
+++ b/src/modules/motion.h
@@ -140,7 +140,7 @@ public:
     /// Get current acceleration for the selected axis
     /// @param axis axis affected
     /// @returns acceleration
-    steps_t Acceleration(Axis axis) {
+    steps_t Acceleration(Axis axis) const {
         return axisData[axis].ctrl.Acceleration();
     }