diff --git a/cxx/mount.h b/cxx/mount.h
index d14e4b4..083c51f 100644
--- a/cxx/mount.h
+++ b/cxx/mount.h
@@ -87,8 +87,9 @@ struct MccMountPosition {
     mnt_coord_t mntAZ, mntZD;
     mnt_coord_t mntPA;
 
-    // encoder-measured current mount moving speed (in radians/s)
+    // encoder-measured (non-corrected for PCS) current mount position and moving speed (in radians, radians/s)
     // X - HA, Y - DEC for equatorial-type mount; X - AZ, Y - ZD for horizontal-type one
+    mnt_coord_t mntPosX, mntPosY;
     mnt_speed_t mntSpeedX, mntSpeedY;
 
     // current refraction coefficient (for tagZD)
diff --git a/cxx/mount_state.h b/cxx/mount_state.h
index 63c8661..4928946 100644
--- a/cxx/mount_state.h
+++ b/cxx/mount_state.h
@@ -6,8 +6,15 @@
 namespace mcc::traits
 {
 
-template <typename T, mcc::MccMountType MOUNT_TYPE>
-concept mcc_mount_c = std::derived_from<T, mcc::MccMount<MOUNT_TYPE>>;
+// template <typename T, mcc::MccMountType MOUNT_TYPE>
+// concept mcc_mount_c = std::derived_from<T, mcc::MccMount<MOUNT_TYPE>>;
+
+template <typename T>
+concept mcc_mount_c = requires {
+    typename T::mount_config_t;
+    requires std::same_as<decltype(T::mountType), MccMountType>;
+    requires std::derived_from<T, mcc::MccMount<T::mountType, typename T::mount_config_t>>;
+};
 
 }  // namespace mcc::traits
 
@@ -28,8 +35,7 @@ public:
     // helper
     static constexpr auto mcc_noop_callback = [](const mount_state_error_t&) {};
 
-    template <MccMountType MOUNT_TYPE>
-    MccMountAbstractState(traits::mcc_mount_c<MOUNT_TYPE> auto* mount_ptr,
+    MccMountAbstractState(traits::mcc_mount_c auto* mount_ptr,
                           std::convertible_to<enter_callback_t> auto&& enter_callback,
                           std::convertible_to<exit_callback_t> auto&& exit_callback,
                           std::convertible_to<error_callback_t> auto&& error_callback)
@@ -74,4 +80,27 @@ public:
     }
 };
 
+
+
+/*  */
+class MccMountStateSlew
+{
+public:
+    enum coords_kind_t { COORDS_KIND_RADEC_IRCS, COORDS_KIND_RADEC_APP, COORDS_KIND_HADEC_APP, COORDS_KIND_AZALT };
+
+    struct slew_state_params_t {
+        coords_kind_t coordKind{COORDS_KIND_RADEC_APP};
+        MccAngle x, y;  // according to 'coordKind'
+
+        bool stop{false};  // stop after
+    };
+
+    MccMountStateSlew() {}
+
+    std::string_view ident() const
+    {
+        return "MCC-MOUNT-STATE-SLEW";
+    }
+};
+
 }  // namespace mcc