diff --git a/cxx/CMakeLists.txt b/cxx/CMakeLists.txt
index 276899d..1341366 100644
--- a/cxx/CMakeLists.txt
+++ b/cxx/CMakeLists.txt
@@ -123,13 +123,19 @@ set(CNTR_PROTO_LIB comm_proto)
 add_library(${CNTR_PROTO_LIB} STATIC ${CNTR_PROTO_LIB_SRC})
 
 
-set(MCC_LIBRARY_SRC mcc_mount_concepts.h mcc_mount.h mcc_mount_coord.h mcc_mount_events_states.h mcc_finite_state_machine.h
-    mcc_mount_pec.h mcc_mount_pz.h mcc_traits.h mcc_mount_telemetry.h mcc_mount_config.h mcc_mount_astro_erfa.h mcc_astrom_iers.h mcc_astrom_iers_default.h mcc_utils.h)
+set(MCC_LIBRARY_SRC mcc_mount_concepts.h mcc_fsm_mount.h mcc_mount_coord.h mcc_mount_events_states.h mcc_finite_state_machine.h
+    mcc_mount_pec.h mcc_mount_pz.h mcc_traits.h mcc_mount_telemetry.h mcc_mount_config.h mcc_mount_astro_erfa.h mcc_astrom_iers.h mcc_astrom_iers_default.h
+    mcc_utils.h mcc_spdlog.h)
 set(MCC_LIBRARY mcc)
 add_library(${MCC_LIBRARY} INTERFACE ${MCC_LIBRARY_SRC})
 target_compile_features(${MCC_LIBRARY} INTERFACE cxx_std_23)
 target_include_directories(${MCC_LIBRARY} INTERFACE ${FITPACK_INCLUDE_DIR})
 
+
+set(ASIBFM700_LIB_SRC asibfm700_hardware.h asibfm700_hardware.cpp)
+set(ASIBFM700_LIB asibfm700)
+add_library(${ASIBFM700_LIB} STATIC ${ASIBFM700_LIB_SRC})
+
 # set(MOUNT_SERVER_APP_SRC mount.h mount_state.h mount_server.cpp comm_server.h comm_server_endpoint.h comm_server_configfile.h mount_astrom.h
 #     mount_astrom_default.h mcc_coord.h mount_pz.h mcc_fsm.h mcc_fsm_utils.h mcc_finite_state_machine.h mcc_mount_events_states.h)
 # set(MOUNT_SERVER_APP mount_server)
diff --git a/cxx/asibfm700_hardware.cpp b/cxx/asibfm700_hardware.cpp
new file mode 100644
index 0000000..0d1492e
--- /dev/null
+++ b/cxx/asibfm700_hardware.cpp
@@ -0,0 +1,138 @@
+#include "asibfm700_hardware.h"
+
+using namespace asibfm700;
+
+
+/*                          error category implementation  */
+
+const char* AsibFM700HardwareErrorCategory::name() const noexcept
+{
+    return "ASTROSIB FM700 MOUNT HARDWARE ERROR CATEGORY";
+}
+
+std::string AsibFM700HardwareErrorCategory::message(int ec) const
+{
+    AsibFM700HardwareErrorCode code = static_cast<AsibFM700HardwareErrorCode>(ec);
+
+    std::string msg;
+
+    switch (code) {
+        case AsibFM700HardwareErrorCode::ERROR_OK:
+            msg = "OK";
+        case asibfm700::AsibFM700HardwareErrorCode::ERROR_FATAL:
+            msg = "fatal hardware error";
+        case AsibFM700HardwareErrorCode::ERROR_BADFORMAT:
+            msg = "wrong arguments of function";
+        case AsibFM700HardwareErrorCode::ERROR_ENCODERDEV:
+            msg = "encoder device error or can't open";
+        case AsibFM700HardwareErrorCode::ERROR_MOUNTDEV:
+            msg = "mount device error or can't open";
+        case AsibFM700HardwareErrorCode::ERROR_FAILED:
+            msg = "failed to run command - protocol error";
+        default:
+            msg = "UNKNOWN ERROR";
+    }
+
+    return msg;
+}
+
+const AsibFM700HardwareErrorCategory& AsibFM700HardwareErrorCategory::get()
+{
+    static const AsibFM700HardwareErrorCategory constInst;
+    return constInst;
+}
+
+
+
+/*                          AsibFM700Hardware CLASS IMPLEMENTATION  */
+
+
+/*  static methods  */
+
+// void AsibFM700Hardware::moveInst(AsibFM700Hardware* from, AsibFM700Hardware* to)
+// {
+//     to->_hwConfig = std::move(from->_hwConfig);
+//     to->_deviceConfig = std::move(from->_deviceConfig);
+
+//     from->_deviceConfig.MountDevPath = nullptr;
+//     from->_deviceConfig.EncoderDevPath = nullptr;
+//     from->_deviceConfig.EncoderXDevPath = nullptr;
+//     from->_deviceConfig.EncoderYDevPath = nullptr;
+// }
+
+/*  constructors and destructor  */
+
+AsibFM700Hardware::AsibFM700Hardware(const hardware_config_t& conf) : _hardwareConfig(conf)
+{
+    _hardwareConfig.devConfig.MountDevPath = const_cast<char*>(_hardwareConfig.MountDevPath.c_str());
+    _hardwareConfig.devConfig.EncoderDevPath = const_cast<char*>(_hardwareConfig.EncoderDevPath.c_str());
+    _hardwareConfig.devConfig.EncoderXDevPath = const_cast<char*>(_hardwareConfig.EncoderXDevPath.c_str());
+    _hardwareConfig.devConfig.EncoderYDevPath = const_cast<char*>(_hardwareConfig.EncoderYDevPath.c_str());
+}
+
+// AsibFM700Hardware::AsibFM700Hardware(AsibFM700Hardware&& other)
+// {
+//     moveInst(&other, this);
+// }
+
+// AsibFM700Hardware& AsibFM700Hardware::operator=(AsibFM700Hardware&& other)
+// {
+//     moveInst(&other, this);
+
+//     return *this;
+// }
+
+AsibFM700Hardware::~AsibFM700Hardware() {}
+
+std::string_view AsibFM700Hardware::id() const
+{
+    return "Sidereal Technology Servo II controller";
+}
+
+
+
+AsibFM700Hardware::error_t AsibFM700Hardware::setPos(AsibFM700Hardware::axes_pos_t pos)
+{
+    double X = pos.x, Y = pos.y;
+    auto err = static_cast<AsibFM700HardwareErrorCode>(Mount.moveTo(&X, &Y));
+
+    return err;
+}
+
+
+
+AsibFM700Hardware::error_t AsibFM700Hardware::getPos(AsibFM700Hardware::axes_pos_t& pos)
+{
+    mountdata_t data;
+    auto err = static_cast<AsibFM700HardwareErrorCode>(Mount.getMountData(&data));
+
+    if (err == AsibFM700HardwareErrorCode::ERROR_OK) {
+        // time point from sidservo library is 'struct timeval', i.e., seconds and
+        // microseconds ellapsed from UNIX time epoch
+
+        using secs_t = std::chrono::duration<double>;
+        secs_t secs = secs_t{1.0 * data.encposition.msrtime.tv_sec + 1.0E-6 * data.encposition.msrtime.tv_usec};
+
+        pos.time_point = time_point_t{std::chrono::duration_cast<time_point_t::duration>(secs)};
+
+        pos.x = data.encposition.X;
+        pos.y = data.encposition.Y;
+    }
+
+    return err;
+}
+
+
+AsibFM700Hardware::error_t AsibFM700Hardware::stop()
+{
+    auto err = static_cast<AsibFM700HardwareErrorCode>(Mount.stop());
+
+    return err;
+}
+
+AsibFM700Hardware::error_t AsibFM700Hardware::init()
+{
+    auto err = static_cast<AsibFM700HardwareErrorCode>(Mount.init(&_hardwareConfig.devConfig));
+
+    return err;
+}
diff --git a/cxx/asibfm700_hardware.h b/cxx/asibfm700_hardware.h
new file mode 100644
index 0000000..2188cb1
--- /dev/null
+++ b/cxx/asibfm700_hardware.h
@@ -0,0 +1,128 @@
+#pragma once
+
+/*                          AstroSIB-FM700 FORK MOUNT CONTROL LIBRARY                           */
+
+/*                          HARDWARE WRAPPER IMPLEMENTATION                         */
+
+#include "../LibSidServo/sidservo.h"
+
+#include "mcc_mount_concepts.h"
+#include "mcc_mount_coord.h"
+
+
+namespace asibfm700
+{
+
+/*  error codes enum definition  */
+
+enum class AsibFM700HardwareErrorCode : int {
+    // error codes from sidservo library
+    ERROR_OK = MCC_E_OK,
+    ERROR_FATAL = MCC_E_FATAL,
+    ERROR_BADFORMAT = MCC_E_BADFORMAT,
+    ERROR_ENCODERDEV = MCC_E_ENCODERDEV,
+    ERROR_MOUNTDEV = MCC_E_MOUNTDEV,
+    ERROR_FAILED = MCC_E_FAILED,
+    // my codes ...
+};
+
+// error category
+struct AsibFM700HardwareErrorCategory : public std::error_category {
+    const char* name() const noexcept;
+    std::string message(int ec) const;
+
+    static const AsibFM700HardwareErrorCategory& get();
+};
+
+
+inline std::error_code make_error_code(AsibFM700HardwareErrorCode ec)
+{
+    return std::error_code(static_cast<int>(ec), AsibFM700HardwareErrorCategory::get());
+}
+
+}  // namespace asibfm700
+
+
+namespace std
+{
+
+template <>
+class is_error_code_enum<asibfm700::AsibFM700HardwareErrorCode> : public true_type
+{
+};
+
+}  // namespace std
+
+
+
+namespace asibfm700
+{
+
+class AsibFM700Hardware final
+{
+public:
+    // definitions from concept
+    typedef std::error_code error_t;
+    typedef mcc::MccAngle coord_t;
+    typedef std::chrono::system_clock::time_point time_point_t;  // UTC time
+
+    struct axes_pos_t {
+        time_point_t time_point;
+        coord_t x, y;
+    };
+
+    // c++ish wrapper to 'conf_t' struct
+
+    struct device_config_t {
+        std::string MountDevPath;    // path to mount device
+        int MountDevSpeed;           // serial speed
+        std::string EncoderDevPath;  // path to encoder device
+        int EncoderDevSpeed;         // serial speed
+        int SepEncoder;  // ==1 if encoder works as separate serial device, ==2 if there's new version with two devices
+        std::string EncoderXDevPath;  // paths to new controller devices
+        std::string EncoderYDevPath;
+        double MountReqInterval;    // interval between subsequent mount requests (seconds)
+        double EncoderReqInterval;  // interval between subsequent encoder requests (seconds)
+    };
+
+
+    struct hardware_config_t {
+        // the 'char*' fields from conf_t:
+        //    wrap it to std::string
+        std::string MountDevPath;
+        std::string EncoderDevPath;
+        std::string EncoderXDevPath;
+        std::string EncoderYDevPath;
+
+        conf_t devConfig;
+        hardware_configuration_t hwConfig;
+    };
+
+    AsibFM700Hardware(const hardware_config_t& conf);
+
+    ~AsibFM700Hardware();
+
+    AsibFM700Hardware(const AsibFM700Hardware&) = delete;
+    AsibFM700Hardware& operator=(const AsibFM700Hardware&) = delete;
+
+    AsibFM700Hardware(AsibFM700Hardware&&) = default;
+    AsibFM700Hardware& operator=(AsibFM700Hardware&&) = default;
+
+
+    std::string_view id() const;
+
+    error_t setPos(axes_pos_t);
+    error_t getPos(axes_pos_t&);
+    error_t stop();
+    error_t init();
+
+private:
+    hardware_config_t _hardwareConfig;
+
+    // static void moveInst(AsibFM700Hardware* from, AsibFM700Hardware* to);
+};
+
+static_assert(mcc::traits::mcc_mount_hardware_c<AsibFM700Hardware>, "AsibFM700Hardware!!!");
+
+
+}  // namespace asibfm700
diff --git a/cxx/mcc_finite_state_machine.h b/cxx/mcc_finite_state_machine.h
index caa6717..2473076 100644
--- a/cxx/mcc_finite_state_machine.h
+++ b/cxx/mcc_finite_state_machine.h
@@ -7,6 +7,7 @@
 
 #include <concepts>
 #include <functional>
+#include <future>
 #include <memory>
 #include <mutex>
 #include <string_view>
@@ -318,7 +319,7 @@ protected:
     std::vector<std::string_view> _eventID{};
 
     std::recursive_mutex _transitionMutex{};
-
+    std::future<void> _currentStateThreadFuture;
 
     static MccFiniteStateMachine& copyInstance(const MccFiniteStateMachine* from, MccFiniteStateMachine* to)
     {
@@ -400,7 +401,6 @@ public:
                                   if constexpr (requires(curr_state_t inst) {
                                                     { inst.exit(std::declval<EvT&>()) };
                                                 }) {
-                                      // std::get<curr_state_t>(*states).exit(event);
                                       std::get<curr_state_t>(*states).exit(*p_event);
                                   } else if constexpr (requires(curr_state_t inst) {
                                                            { inst.exit() };
@@ -412,7 +412,6 @@ public:
                                   if constexpr (requires(EvT inst) {
                                                     { inst.onTransit() };
                                                 }) {
-                                      // event.onTransit();
                                       p_event->onTransit();
                                   }
 
@@ -423,7 +422,6 @@ public:
                                   if constexpr (requires(to_state_t inst) {
                                                     { inst.enter(std::declval<EvT&>()) };
                                                 }) {
-                                      // std::get<to_state_t>(*states).enter(event);
                                       std::get<to_state_t>(*states).enter(*p_event);
                                   } else if constexpr (requires(to_state_t inst) {
                                                            { inst.enter() };
diff --git a/cxx/mcc_mount.h b/cxx/mcc_fsm_mount.h
similarity index 73%
rename from cxx/mcc_mount.h
rename to cxx/mcc_fsm_mount.h
index 4194db3..0f7e129 100644
--- a/cxx/mcc_mount.h
+++ b/cxx/mcc_fsm_mount.h
@@ -1,42 +1,45 @@
 #pragma once
 
-/*  MOUNT CONTROL COMPONENTS LIBRARY  */
+/*                          MOUNT CONTROL COMPONENTS LIBRARY                            */
 
-/*  AN GENERIC MOUNT CLASS IMPLEMENTATION  */
 
-// #include <atomic>
+
+/*                          AN GENERIC MOUNT CLASS IMPLEMENTATION BASED ON FINITE STATE MACHINE */
+
 #include <chrono>
-// #include <concepts>
-// #include <cstdint>
 #include <functional>
 #include <string_view>
 #include "spdlog/sinks/null_sink.h"
 
-#include "mcc_finite_state_machine.h"
+#include "mcc_mount_concepts.h"
 #include "mcc_mount_coord.h"
 #include "mcc_spdlog.h"
 #include "mcc_traits.h"
-// #include "mount_astrom.h"
-// #include "mcc_mount_pz.h"
-#include "mcc_mount_concepts.h"
+
+
+#include "mcc_finite_state_machine.h"
+#include "mcc_mount_events_states.h"
 
 namespace mcc
 {
 
-
-template <traits::mcc_mount_config_c MOUNT_CONFIG>
-class MccMount : public fsm::MccFiniteStateMachine, public utils::MccSpdlogLogger
+template <traits::mcc_mount_controls_c MOUNT_CONTROLS>
+class MccMount : public fsm::MccFiniteStateMachine, public utils::MccSpdlogLogger, protected MOUNT_CONTROLS
 {
+    // declare these classes as friends to allow them access protected members 'slewModel' and 'guidingModel'
+    friend class MccMountStateSlew<MccMount>;
+    friend class MccMountStateGuiding<MccMount>;
+
 public:
-    typedef MOUNT_CONFIG mount_config_t;
-    typedef decltype(mount_config_t::telemetry) mount_telemetry_t;
+    typedef MOUNT_CONTROLS mount_controls_t;
+    typedef decltype(mount_controls_t::telemetry) mount_telemetry_t;
     typedef typename mount_telemetry_t::mount_telemetry_data_t mount_telemetry_data_t;
 
-    typedef decltype(mount_config_t::astrometryEngine) astrom_engine_t;
-    typedef decltype(mount_config_t::PEC) pec_t;
-    typedef decltype(mount_config_t::hardware) hardware_t;
-    typedef decltype(mount_config_t::slewModel) slew_model_t;
-    typedef decltype(mount_config_t::guidingModel) guiding_model_t;
+    typedef decltype(mount_controls_t::astrometryEngine) astrom_engine_t;
+    typedef decltype(mount_controls_t::PEC) pec_t;
+    typedef decltype(mount_controls_t::hardware) hardware_t;
+    typedef decltype(mount_controls_t::slewModel) slew_model_t;
+    typedef decltype(mount_controls_t::guidingModel) guiding_model_t;
 
     typedef typename slew_model_t::slew_params_t slew_params_t;
 
@@ -44,16 +47,13 @@ public:
     /*  constructors and destructor  */
 
     template <fsm::traits::fsm_state_c InitStateT, traits::mcc_input_char_range LogMarkT = std::string_view>
-    MccMount(mount_config_t mount_config,
+    MccMount(mount_controls_t mount_controls,
              InitStateT,
              std::shared_ptr<spdlog::logger> logger = spdlog::null_logger_mt("NULL"),
              const LogMarkT& logger_mark = "[MOUNT]")
         : fsm::MccFiniteStateMachine(InitStateT{}),
           utils::MccSpdlogLogger(logger),
-          _mountConfig(std::move(mount_config)),
-          _mountTelemetry(_mountConfig.telemetry),
-          _slewModel(_mountConfig.slewModel),
-          _guidingModel(_mountConfig.guidingModel)
+          mount_controls_t(std::move(mount_controls))
     {
         addMarkToPatternIdx(logger_mark);
 
@@ -87,24 +87,11 @@ public:
     void startGuiding() {}
 
 
-    // mount_config_t mountConfig() const
-    // {
-    //     return _mountConfig;
-    // }
-
-    // returns "mount_config_t&" or "mount_config_t const&"
-    decltype(auto) mountConfig(this auto&& self)
-    {
-        auto& config_ref = std::forward<decltype(self)>(self)._mountConfig;
-
-        return config_ref;
-    }
-
     mount_telemetry_data_t mountTelemetryData() const
     {
         mount_telemetry_data_t mnt_data;
 
-        auto err = _mountTelemetry.data(mnt_data);
+        auto err = this->telemetry.data();
         if (err) {
             // log ....
         }
@@ -149,11 +136,6 @@ public:
 
 
 protected:
-    mount_config_t _mountConfig;
-    mount_telemetry_t& _mountTelemetry;
-    slew_model_t& _slewModel;
-    guiding_model_t& _guidingModel;
-
     // a type to which the result of calling prohibited zone class methods 'timeTo' and 'timeFrom' will be converted
     typedef std::chrono::duration<double> pz_duration_t;  // seconds as floating-point number
 
@@ -191,13 +173,14 @@ protected:
 };  // end of MccMount class
 
 
-namespace traits
-{
 
-// given mount class must be a descendant of MccMount
-template <typename T>
-concept mcc_mount_c = requires(T t) { []<typename... Ts>(MccMount<Ts...>*) {}(&t); };
+// namespace traits
+// {
 
-}  // namespace traits
+// // given mount class must be a descendant of MccMount
+// template <typename T>
+// concept mcc_mount_c = requires(T t) { []<typename... Ts>(MccMount<Ts...>*) {}(&t); };
+
+// }  // namespace traits
 
 }  // namespace mcc
diff --git a/cxx/mcc_mount_concepts.h b/cxx/mcc_mount_concepts.h
index f5ca3ec..2d43117 100644
--- a/cxx/mcc_mount_concepts.h
+++ b/cxx/mcc_mount_concepts.h
@@ -4,10 +4,10 @@
 
 #include <concepts>
 
+#include "mcc_finite_state_machine.h"
 #include "mcc_mount_coord.h"
 #include "mcc_traits.h"
 
-
 /*  SOME LIBRARY-WIDE DECLARATIONS  */
 
 namespace mcc
@@ -63,6 +63,22 @@ namespace mcc::traits
 {
 
 
+/*  GENERIC LOGGER  */
+
+template <typename T>
+concept mcc_logger_c = requires(T t, const T t_const) {
+    typename T::loglevel_t;
+    { t.setLogLevel(std::declval<typename T::loglevel_t>()) };
+    { t_const.getLogLevel() } -> std::same_as<typename T::loglevel_t>;
+
+    { t.logMessage(std::declval<typename T::loglevel_t>(), std::declval<const std::string&>()) };
+
+    { t.logError(std::declval<const std::string&>()) };
+    { t.logDebug(std::declval<const std::string&>()) };
+    { t.logWarn(std::declval<const std::string&>()) };
+    { t.logInfo(std::declval<const std::string&>()) };
+};
+
 /*  ASTROMETRY-RELATED COMPUTATION ENGINE  */
 
 template <typename T>
@@ -171,6 +187,7 @@ concept mcc_mount_hardware_c = !std::copyable<T> && std::movable<T> && requires(
     { t.setPos(std::declval<typename T::axes_pos_t>()) } -> std::same_as<typename T::error_t>;
     { t.getPos(std::declval<typename T::axes_pos_t&>()) } -> std::same_as<typename T::error_t>;
     { t.stop() } -> std::same_as<typename T::error_t>;
+    { t.init() } -> std::same_as<typename T::error_t>;
 };
 
 
@@ -235,12 +252,14 @@ concept mcc_mount_telemetry_c = requires(T t, const T t_const) {
     // // a class that at least contains celestial (equatorial and horizontal) coordinates
     // requires requires(typename T::mount_telemetry_data_t telemetry) {
     //     typename T::mount_telemetry_data_t::coord_t;
-    //     requires std::same_as<decltype(telemetry.mntRA), typename T::mount_telemetry_data_t::coord_t>;   // apparent
-    //     RA requires std::same_as<decltype(telemetry.mntDEC), typename T::mount_telemetry_data_t::coord_t>;  //
-    //     apparent DEC requires std::same_as<decltype(telemetry.mntHA), typename T::mount_telemetry_data_t::coord_t>;
-    //     // hour angle requires std::same_as<decltype(telemetry.mntAZ), typename T::mount_telemetry_data_t::coord_t>;
-    //     // azimuth requires std::same_as<decltype(telemetry.mntALT), typename T::mount_telemetry_data_t::coord_t>; //
-    //     altitude
+    //     requires std::same_as<decltype(telemetry.mntRA), typename T::mount_telemetry_data_t::coord_t>;   //
+    //     apparent RA requires std::same_as<decltype(telemetry.mntDEC), typename
+    //     T::mount_telemetry_data_t::coord_t>;  // apparent DEC requires std::same_as<decltype(telemetry.mntHA),
+    //     typename T::mount_telemetry_data_t::coord_t>;
+    //     // hour angle requires std::same_as<decltype(telemetry.mntAZ), typename
+    //     T::mount_telemetry_data_t::coord_t>;
+    //     // azimuth requires std::same_as<decltype(telemetry.mntALT), typename
+    //     T::mount_telemetry_data_t::coord_t>; // altitude
     // };
 
     requires mcc_mount_telemetry_data_c<typename T::mount_telemetry_data_t>;
@@ -336,8 +355,8 @@ concept mcc_prohibited_zone_c =
 
 
         // for given coordinates and time the method computes a time to reach the zone.
-        // implementation of the method must assume that input coordinates are apparent RA and DEC at given time point,
-        // while the time point is one from which computation should be performed (e.g. current time moment)
+        // implementation of the method must assume that input coordinates are apparent RA and DEC at given time
+        // point, while the time point is one from which computation should be performed (e.g. current time moment)
         {
             t.timeTo(std::declval<typename T::coord_t>(), std::declval<typename T::coord_t>(),
                      std::declval<typename T::time_point_t>())
@@ -369,11 +388,11 @@ concept mcc_prohibited_zone_c =
 
 
 
-/*  MOUNT GENERIC CONFIGURATION  */
+/*  MOUNT GENERIC CONTROLS  */
 
 
 template <typename T>
-concept mcc_mount_config_c = std::movable<T> && requires(T t) {
+concept mcc_mount_controls_c = std::move_constructible<T> && std::movable<T> && requires(T t) {
     requires mcc_astrom_engine_c<decltype(t.astrometryEngine)>;
     requires mcc_mount_pec_c<decltype(t.PEC)>;
     requires mcc_mount_hardware_c<decltype(t.hardware)>;
@@ -388,5 +407,37 @@ concept mcc_mount_config_c = std::movable<T> && requires(T t) {
 };
 
 
+/*                                      GENERIC MOUNT CONCEPTS                          */
+
+template <typename T>
+concept mcc_mount_c = requires(T t) {
+    // the class must define typename 'mount_controls_t' and it must be its base class
+    requires mcc_mount_controls_c<typename T::mount_controls_t>;
+    requires std::derived_from<T, typename T::mount_controls_t>;
+
+
+    // deduced from 'mount_controls_t' typenames
+    requires mcc_mount_telemetry_c<typename T::mount_telemetry_t>;
+    requires std::same_as<typename T::mount_telemetry_data_t, typename T::mount_telemetry_t::mount_telemetry_data_t>;
+    requires mcc_astrom_engine_c<typename T::astrom_engine_t>;
+    requires mcc_mount_pec_c<typename T::pec_t>;
+    requires mcc_mount_hardware_c<typename T::hardware_t>;
+    requires mcc_slew_model_c<typename T::slew_model_t, typename T::mount_telemetry_t>;
+    requires mcc_guiding_model_c<typename T::guiding_model_t, typename T::mount_telemetry_t>;
+
+    requires std::same_as<typename T::slew_params_t, typename T::slew_model_t::slew_params_t>;
+
+    // public method
+    { t.mountTelemetryData() } -> std::same_as<typename T::mount_telemetry_data_t>;
+};
+
+// generic with logging methods
+template <typename T>
+concept mcc_log_mount_c = mcc_mount_c<T> && mcc_logger_c<T>;
+
+
+// a generic Finite State Machine mount with logging methods
+template <typename T>
+concept mcc_fsm_log_mount_c = std::derived_from<T, fsm::MccFiniteStateMachine> && mcc_log_mount_c<T>;
 
 }  // namespace mcc::traits
diff --git a/cxx/mcc_mount_coord.h b/cxx/mcc_mount_coord.h
index ac22131..6d7e65b 100644
--- a/cxx/mcc_mount_coord.h
+++ b/cxx/mcc_mount_coord.h
@@ -349,11 +349,18 @@ public:
     }
 
 
+    // unary '-' and '+'
     template <typename SelfT>
-    SelfT& operator-(this SelfT& self)
+    SelfT operator-(this SelfT& self)
     {
-        self._angleInRads = -self._angleInRads;
+        SelfT res = -self._angleInRads;
 
+        return res;
+    }
+
+    template <typename SelfT>
+    SelfT operator+(this SelfT& self)
+    {
         return self;
     }
 };
diff --git a/cxx/mcc_mount_events_states.h b/cxx/mcc_mount_events_states.h
index b7a0c84..e5ecbf4 100644
--- a/cxx/mcc_mount_events_states.h
+++ b/cxx/mcc_mount_events_states.h
@@ -3,12 +3,13 @@
 /*  MOUNT CONTROL COMPONENTS LIBRARY  */
 
 /*
- *  BASIC EVENTS AND MOUNT STATES DEFINITIONS (REFERENCE IMPLEMENTATION)
+ *  BASIC EVENTS AND MOUNT STATES DEFINITIONS (POSSIBLE IMPLEMENTATION)
  *
  */
 
+#include <format>
 
-#include "mcc_mount.h"
+#include "mcc_mount_concepts.h"
 
 namespace mcc
 {
@@ -19,7 +20,7 @@ namespace mcc
 
 // a base class for mount state machine events
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 class MccMountEventBase
 {
 public:
@@ -41,7 +42,7 @@ protected:
 
 // transit to IDLE state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountEventIDLE : public MccMountEventBase<MountT> {
     typedef MccMountEventBase<MountT> base_t;
 
@@ -55,7 +56,7 @@ struct MccMountEventIDLE : public MccMountEventBase<MountT> {
 
 // transit to initialization state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountEventInit : public MccMountEventBase<MountT> {
     typedef MccMountEventBase<MountT> base_t;
 
@@ -69,7 +70,7 @@ struct MccMountEventInit : public MccMountEventBase<MountT> {
 
 // transit to error state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountEventError : public MccMountEventBase<MountT> {
     typedef MccMountEventBase<MountT> base_t;
 
@@ -91,7 +92,7 @@ protected:
 
 // transit to slew state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountEventSlew : public MccMountEventBase<MountT> {
     typedef MccMountEventBase<MountT> base_t;
 
@@ -113,7 +114,7 @@ protected:
 
 // transit to guiding state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountEventGuiding : public MccMountEventBase<MountT> {
     typedef MccMountEventBase<MountT> base_t;
 
@@ -127,7 +128,7 @@ struct MccMountEventGuiding : public MccMountEventBase<MountT> {
 
 // transit to stop state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountEventStop : public MccMountEventBase<MountT> {
     typedef MccMountEventBase<MountT> base_t;
 
@@ -159,7 +160,7 @@ protected:
 
 // transit to shutdown state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountEventShutdown : public MccMountEventBase<MountT> {
     typedef MccMountEventBase<MountT> base_t;
 
@@ -173,7 +174,7 @@ struct MccMountEventShutdown : public MccMountEventBase<MountT> {
 
 /*  MOUNT STATE MACHINE STATES  */
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateBase {
     // template <std::derived_from<MccMountEventBase<MountT>> EvT>
     // void exit(this auto&& self, EvT& event)
@@ -214,45 +215,46 @@ protected:
     void exitLog(this auto&& self, EvT& event)
     {
         using self_t = std::remove_cvref_t<decltype(self)>;
-        event.mount().logDebug("Exit from '{}' state due to '{}' event ...", self_t::ID, EvT::ID);
+
+        event.mount().logDebug(std::format("Exit from '{}' state due to '{}' event ...", self_t::ID, EvT::ID));
     }
 
     template <std::derived_from<MccMountEventBase<MountT>> EvT>
     void enterLog(this auto&& self, EvT& event)
     {
         using self_t = std::remove_cvref_t<decltype(self)>;
-        event.mount().logDebug("Enter to '{}' state due to '{}' event ...", self_t::ID, EvT::ID);
+        event.mount().logDebug(std::format("Enter to '{}' state due to '{}' event ...", self_t::ID, EvT::ID));
     }
 };
 
 
 
 // just forward declarations
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateIDLE;
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateInit;
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateError;
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateSlew;
 
-template <traits::mcc_mount_c MountT, fsm::traits::fsm_event_c TrEvT = MccMountEventStop<MountT>>
+template <traits::mcc_fsm_log_mount_c MountT, fsm::traits::fsm_event_c TrEvT = MccMountEventStop<MountT>>
 struct MccMountStateStop;
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateGuiding;
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateShutdown;
 
 
 // stop state
 
-template <traits::mcc_mount_c MountT, fsm::traits::fsm_event_c TrEvT>
+template <traits::mcc_fsm_log_mount_c MountT, fsm::traits::fsm_event_c TrEvT>
 struct MccMountStateStop : MccMountStateBase<MountT> {
     static constexpr std::string_view ID = "MCC-MOUNT-STOP-STATE";
 
@@ -287,7 +289,7 @@ struct MccMountStateStop : MccMountStateBase<MountT> {
         mount.stopMount();
 
         if constexpr (std::same_as<EvT, MccMountEventStop<MountT>>) {
-            mount.logInfo("Stop reason: {}", event.reason());
+            mount.logInfo(std::format("Stop reason: {}", event.reason()));
 
             // normal behavior (transit to IDLE state after stopping)
             mount.template dispatchEvent<MccMountEventIDLE<MountT>>({mount});
@@ -300,7 +302,7 @@ struct MccMountStateStop : MccMountStateBase<MountT> {
 
 // initialization state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateInit : MccMountStateBase<MountT> {
     static constexpr std::string_view ID = "MCC-MOUNT-INIT-STATE";
 
@@ -329,7 +331,7 @@ struct MccMountStateInit : MccMountStateBase<MountT> {
 
 // error state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateError : MccMountStateBase<MountT> {
     static constexpr std::string_view ID = "MCC-MOUNT-ERROR-STATE";
 
@@ -348,9 +350,9 @@ struct MccMountStateError : MccMountStateBase<MountT> {
     {
         this->exitLog(event);
 
-        event.mount().logWarn(
+        event.mount().logWarn(std::format(
             "The mount is in the error state!!! One must correct it before transit to any states! Event type is '{}'",
-            EvT::ID);
+            EvT::ID));
     }
 
     void exit(MccMountEventIDLE<MountT>& event)
@@ -372,8 +374,8 @@ struct MccMountStateError : MccMountStateBase<MountT> {
 
         auto err = event.eventData();
 
-        event.mount().logError("The mount is in the error state: code = {}, category = {}, message = '{}'", err.value(),
-                               err.category().name(), err.message());
+        event.mount().logError(std::format("The mount is in the error state: code = {}, category = {}, message = '{}'",
+                                           err.value(), err.category().name(), err.message()));
     }
     // template <std::derived_from<MccMountEventBase<MountT>> EvT>
     // void enter(EvT& event)
@@ -391,7 +393,7 @@ struct MccMountStateError : MccMountStateBase<MountT> {
 
 // IDLE state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateIDLE : MccMountStateBase<MountT> {
     static constexpr std::string_view ID = "MCC-MOUNT-IDLE-STATE";
 
@@ -419,7 +421,7 @@ struct MccMountStateIDLE : MccMountStateBase<MountT> {
 
 // shutdown state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateShutdown : MccMountStateBase<MountT> {
     static constexpr std::string_view ID = "MCC-MOUNT-SHUTDOWN-STATE";
 
@@ -445,7 +447,7 @@ struct MccMountStateShutdown : MccMountStateBase<MountT> {
 
 // slew state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateSlew : MccMountStateBase<MountT> {
     static constexpr std::string_view ID = "MCC-MOUNT-SLEW-STATE";
 
@@ -478,7 +480,7 @@ struct MccMountStateSlew : MccMountStateBase<MountT> {
 
 // guiding state
 
-template <traits::mcc_mount_c MountT>
+template <traits::mcc_fsm_log_mount_c MountT>
 struct MccMountStateGuiding : MccMountStateBase<MountT> {
     static constexpr std::string_view ID = "MCC-MOUNT-GUIDING-STATE";
 
diff --git a/cxx/mcc_mount_pz.h b/cxx/mcc_mount_pz.h
index 5d1dde0..ae8f351 100644
--- a/cxx/mcc_mount_pz.h
+++ b/cxx/mcc_mount_pz.h
@@ -53,6 +53,7 @@ public:
         //                                                              : "ALTLIMIT-UNKNOWN"),
         : _altLimit(alt_limit), _latitude(lat), _abs_lat(std::abs(_latitude)), _lat_lim(pi2 - _abs_lat)
     {
+        _lat_lim = pi2 - _abs_lat;
         _altLimit.normalize<MccAngle::NORM_KIND_90_90>();
     }
 
diff --git a/cxx/mcc_mount_telemetry.h b/cxx/mcc_mount_telemetry.h
index 28a6fb6..76cba6b 100644
--- a/cxx/mcc_mount_telemetry.h
+++ b/cxx/mcc_mount_telemetry.h
@@ -3,7 +3,7 @@
 /*  MOUNT CONTROL COMPONENTS LIBRARY  */
 
 
-/*  MOUNT TELEMETRY OBJECT POSSIBLE IMPLEMENTATION  */
+/*  MOUNT TELEMETRY OBJECT POSSIBLE GENERIC IMPLEMENTATION  */
 
 #include <mutex>
 
diff --git a/cxx/mcc_traits.h b/cxx/mcc_traits.h
index d675875..183bcf7 100644
--- a/cxx/mcc_traits.h
+++ b/cxx/mcc_traits.h
@@ -164,8 +164,9 @@ concept mcc_nonconst_lvref = std::is_lvalue_reference_v<T> && !std::is_const_v<s
 
 
 template <typename T>
-concept mcc_error_c = std::convertible_to<T, bool>;
-// concept mcc_error_c = std::convertible_to<T, bool> && mcc_formattable<T>;
+concept mcc_error_c = std::convertible_to<T, bool> || requires(const T t) {
+    { t.operator bool() };
+};
 
 namespace details
 {
diff --git a/cxx/mount_astrom.h b/cxx/mount_astrom.h
index 7af590a..2657315 100644
--- a/cxx/mount_astrom.h
+++ b/cxx/mount_astrom.h
@@ -16,8 +16,8 @@
 #endif
 
 #include "mcc_traits.h"
+#include "mcc_utils.h"
 #include "mount_astrom_default.h"
-#include "utils.h"
 
 namespace erfa
 {