diff --git a/src/logic/command_base.cpp b/src/logic/command_base.cpp
index 2ca28e9..3106ac4 100644
--- a/src/logic/command_base.cpp
+++ b/src/logic/command_base.cpp
@@ -1,25 +1,25 @@
 #include "command_base.h"
 #include "../modules/idler.h"
+#include "../modules/selector.h"
 
 namespace mi = modules::idler;
+namespace ms = modules::selector;
 
 namespace logic {
 
 bool CommandBase::Step() {
     // check the global HW errors - may be we should avoid the modules layer and check for the HAL layer errors directly
-    // @@TODO discuss...
-    bool any_error = mi::idler.State() == mi::Idler::Failed;
-
-    // @@TODO check all other HW issues here to be able to respond with the appropriate error code into the printer
-
-    if (any_error) {
-        state = ProgressCode::ERR1TMCInitFailed;
-        error = ErrorCode::TMC_INIT_ERROR;
-        return true; // the HW error prevents us from continuing with the with the state machine
-        // the MMU must be restarted/fixed before continuing
-    } else {
-        return StepInner();
+    if (mi::idler.State() == mi::Idler::Failed) {
+        state = ProgressCode::ERRTMCFailed;
+        error = ErrorCode::TMC_IOIN_MISMATCH;
+        return true; // the HW error prevents us from continuing with the with the state machine - the MMU must be restarted/fixed before continuing
+    } else if (ms::selector.State() == ms::Selector::Failed) {
+        state = ProgressCode::ERRTMCFailed;
+        error = ErrorCode::TMC_IOIN_MISMATCH;
+        return true; // the HW error prevents us from continuing with the with the state machine - the MMU must be restarted/fixed before continuing
     }
+
+    return StepInner();
 }
 
 } // namespace logic
diff --git a/src/logic/error_codes.h b/src/logic/error_codes.h
index c7978c1..00bb6c9 100644
--- a/src/logic/error_codes.h
+++ b/src/logic/error_codes.h
@@ -1,25 +1,54 @@
 #pragma once
 #include <stdint.h>
 
-/// A complete set of error codes which may be a result of a high-level command/operation
+/// A complete set of error codes which may be a result of a high-level command/operation.
 /// This header file shall be included in the printer's firmware as well as a reference,
-/// therefore the error codes have been extracted to one place
-enum class ErrorCode : int_fast8_t {
-    RUNNING = 0, ///< the operation is still running
-    OK, ///< the operation finished OK
+/// therefore the error codes have been extracted to one place.
+///
+/// Please note the errors are intentionally coded as "negative" values (highest bit set),
+/// becase they are a complement to reporting the state of the high-level state machines -
+/// positive values are considered as normal progress, negative values are errors.
+///
+/// Please note, that multiple TMC errors can occur at once, thus they are defined as a bitmask of the higher byte.
+/// Also, as there are 3 TMC drivers on the board, each error is added a bit for the corresponding TMC -
+/// TMC_PULLEY_BIT, TMC_SELECTOR_BIT, TMC_IDLER_BIT,
+/// The resulting error is a bitwise OR over 3 TMC drivers and their status, which should cover most of the situations correctly.
+enum class ErrorCode : uint_fast16_t {
+    RUNNING = 0x0000, ///< the operation is still running
+    OK = 0x0001, ///< the operation finished OK
 
     /// Unload Filament related error codes
-    FINDA_DIDNT_SWITCH_ON = -1, ///< FINDA didn't switch on while loading filament - either there is something blocking the metal ball or a cable is broken/disconnected
-    FINDA_DIDNT_SWITCH_OFF = -2, ///< FINDA didn't switch off while unloading filament
+    FINDA_DIDNT_SWITCH_ON = 0x8001, ///< FINDA didn't switch on while loading filament - either there is something blocking the metal ball or a cable is broken/disconnected
+    FINDA_DIDNT_SWITCH_OFF = 0x8002, ///< FINDA didn't switch off while unloading filament
 
-    FSENSOR_DIDNT_SWITCH_ON = -3, ///< Filament sensor didn't switch on while performing LoadFilament
-    FSENSOR_DIDNT_SWITCH_OFF = -4, ///< Filament sensor didn't switch off while performing UnloadFilament
+    FSENSOR_DIDNT_SWITCH_ON = 0x8003, ///< Filament sensor didn't switch on while performing LoadFilament
+    FSENSOR_DIDNT_SWITCH_OFF = 0x8004, ///< Filament sensor didn't switch off while performing UnloadFilament
 
-    FILAMENT_ALREADY_LOADED = -5, ///< cannot perform operation LoadFilament or move the selector as the filament is already loaded
+    FILAMENT_ALREADY_LOADED = 0x8005, ///< cannot perform operation LoadFilament or move the selector as the filament is already loaded
 
-    TMC_INIT_ERROR = -6, ///< TMC driver init error - the MMU cannot move one motor due to a HW problem
+    MMU_NOT_RESPONDING = 0x807e, ///< internal error of the printer - communication with the MMU is not working
 
-    MMU_NOT_RESPONDING = -126, ///< internal error of the printer - communication with the MMU is not working
+    INTERNAL = 0x807f, ///< internal runtime error (software)
 
-    INTERNAL = -127, ///< internal runtime error (software)
+    // TMC bit masks
+
+    TMC_PULLEY_BIT = 0x0080, ///< TMC Pulley bit
+    TMC_SELECTOR_BIT = 0x00A0, ///< TMC Pulley bit
+    TMC_IDLER_BIT = 0x00C0, ///< TMC Pulley bit
+
+    TMC_IOIN_MISMATCH = 0x8100, ///< TMC driver init error - TMC dead or bad communication
+
+    /// TMC driver reset - recoverable, we just need to rehome the axis
+    /// Idler: can be rehomed any time
+    /// Selector: if there is a filament, remove it and rehome, if there is no filament, just rehome
+    /// Pulley: do nothing - for the loading sequence - just restart and move slowly, for the unload sequence just restart
+    TMC_RESET = 0x8200,
+
+    TMC_UNDERVOLTAGE_ON_CHARGE_PUMP = 0x8400, ///< not enough current for the TMC, NOT RECOVERABLE
+
+    TMC_SERIOUS_ERROR = 0x8800, ///< TMC driver serious error coil A or coil B - dangerous to recover
+    TMC_ERROR_A = 0x9000, ///< TMC driver error coil A or coil B - can be recovered
+
+    TMC_OVER_TEMPERATURE_WARN = 0xA000, ///< TMC driver over temperature warning - can be recovered by restarting the driver
+    TMC_OVER_TEMPERATURE_ERROR = 0xC000, ///< TMC driver over temperature error - the TMC probably fried
 };
diff --git a/src/logic/load_filament.cpp b/src/logic/load_filament.cpp
index 1467c3a..3089a0f 100644
--- a/src/logic/load_filament.cpp
+++ b/src/logic/load_filament.cpp
@@ -42,7 +42,7 @@ bool LoadFilament::StepInner() {
         if (feed.Step()) {
             if (feed.State() == FeedToFinda::Failed) {
                 // @@TODO - try to repeat 6x - push/pull sequence - probably something to put into feed_to_finda as an option
-                state = ProgressCode::ERR1DisengagingIdler;
+                state = ProgressCode::ERRDisengagingIdler;
                 error = ErrorCode::FINDA_DIDNT_SWITCH_ON;
                 mi::idler.Disengage();
                 ml::leds.SetMode(mg::globals.ActiveSlot(), ml::Color::green, ml::Mode::off);
@@ -74,18 +74,18 @@ bool LoadFilament::StepInner() {
         break;
     case ProgressCode::OK:
         return true;
-    case ProgressCode::ERR1DisengagingIdler: // couldn't unload to FINDA
+    case ProgressCode::ERRDisengagingIdler: // couldn't unload to FINDA
         if (!mi::idler.Engaged()) {
-            state = ProgressCode::ERR1WaitingForUser;
+            state = ProgressCode::ERRWaitingForUser;
             mu::userInput.Clear(); // remove all buffered events if any just before we wait for some input
         }
         return false;
-    case ProgressCode::ERR1WaitingForUser: {
+    case ProgressCode::ERRWaitingForUser: {
         // waiting for user buttons and/or a command from the printer
         mu::Event ev = mu::userInput.ConsumeEvent();
         switch (ev) {
         case mu::Event::Left: // try to manually load just a tiny bit - help the filament with the pulley
-            state = ProgressCode::ERR1EngagingIdler;
+            state = ProgressCode::ERREngagingIdler;
             mi::idler.Engage(mg::globals.ActiveSlot());
             break;
         case mu::Event::Middle: // try again the whole sequence
@@ -102,20 +102,20 @@ bool LoadFilament::StepInner() {
         }
         return false;
     }
-    case ProgressCode::ERR1EngagingIdler:
+    case ProgressCode::ERREngagingIdler:
         if (mi::idler.Engaged()) {
-            state = ProgressCode::ERR1HelpingFilament;
+            state = ProgressCode::ERRHelpingFilament;
             mm::motion.PlanMove(mm::Pulley, 450, 5000); //@@TODO constants
         }
         return false;
-    case ProgressCode::ERR1HelpingFilament:
+    case ProgressCode::ERRHelpingFilament:
         if (mf::finda.Pressed()) {
             // the help was enough to press the FINDA, we are ok, continue normally
             state = ProgressCode::FeedingToBondtech;
             error = ErrorCode::OK;
         } else if (mm::motion.QueueEmpty()) {
             // helped a bit, but FINDA didn't trigger, return to the main error state
-            state = ProgressCode::ERR1DisengagingIdler;
+            state = ProgressCode::ERRDisengagingIdler;
         }
         return false;
     default: // we got into an unhandled state, better report it
diff --git a/src/logic/progress_codes.h b/src/logic/progress_codes.h
index b0d1261..31a5f2b 100644
--- a/src/logic/progress_codes.h
+++ b/src/logic/progress_codes.h
@@ -16,12 +16,12 @@ enum class ProgressCode : uint_fast8_t {
     AvoidingGrind,
     FinishingMoves,
 
-    ERR1DisengagingIdler,
-    ERR1EngagingIdler,
-    ERR1WaitingForUser,
+    ERRDisengagingIdler,
+    ERREngagingIdler,
+    ERRWaitingForUser,
     ERRInternal,
-    ERR1HelpingFilament,
-    ERR1TMCInitFailed,
+    ERRHelpingFilament,
+    ERRTMCFailed,
 
     UnloadingFilament,
     LoadingFilament,
diff --git a/src/logic/unload_filament.cpp b/src/logic/unload_filament.cpp
index a2472bb..57b4fff 100644
--- a/src/logic/unload_filament.cpp
+++ b/src/logic/unload_filament.cpp
@@ -35,7 +35,7 @@ bool UnloadFilament::StepInner() {
         if (unl.Step()) {
             if (unl.State() == UnloadToFinda::Failed) {
                 // couldn't unload to FINDA, report error and wait for user to resolve it
-                state = ProgressCode::ERR1DisengagingIdler;
+                state = ProgressCode::ERRDisengagingIdler;
                 error = ErrorCode::FINDA_DIDNT_SWITCH_OFF;
                 ml::leds.SetMode(mg::globals.ActiveSlot(), ml::red, ml::blink0);
                 ml::leds.SetMode(mg::globals.ActiveSlot(), ml::green, ml::off);
@@ -68,18 +68,18 @@ bool UnloadFilament::StepInner() {
             ml::leds.SetMode(mg::globals.ActiveSlot(), ml::green, ml::on);
         }
         return false;
-    case ProgressCode::ERR1DisengagingIdler: // couldn't unload to FINDA
+    case ProgressCode::ERRDisengagingIdler: // couldn't unload to FINDA
         if (!mi::idler.Engaged()) {
-            state = ProgressCode::ERR1WaitingForUser;
+            state = ProgressCode::ERRWaitingForUser;
             mu::userInput.Clear(); // remove all buffered events if any just before we wait for some input
         }
         return false;
-    case ProgressCode::ERR1WaitingForUser: {
+    case ProgressCode::ERRWaitingForUser: {
         // waiting for user buttons and/or a command from the printer
         mu::Event ev = mu::userInput.ConsumeEvent();
         switch (ev) {
         case mu::Event::Left: // try to manually unload just a tiny bit - help the filament with the pulley
-            state = ProgressCode::ERR1EngagingIdler;
+            state = ProgressCode::ERREngagingIdler;
             mi::idler.Engage(mg::globals.ActiveSlot());
             break;
         case mu::Event::Middle: // try again the whole sequence
@@ -96,20 +96,20 @@ bool UnloadFilament::StepInner() {
         }
         return false;
     }
-    case ProgressCode::ERR1EngagingIdler:
+    case ProgressCode::ERREngagingIdler:
         if (mi::idler.Engaged()) {
-            state = ProgressCode::ERR1HelpingFilament;
+            state = ProgressCode::ERRHelpingFilament;
             mm::motion.PlanMove(mm::Pulley, 450, 5000);
         }
         return false;
-    case ProgressCode::ERR1HelpingFilament:
+    case ProgressCode::ERRHelpingFilament:
         if (!mf::finda.Pressed()) {
             // the help was enough to depress the FINDA, we are ok, continue normally
             state = ProgressCode::DisengagingIdler;
             error = ErrorCode::OK;
         } else if (mm::motion.QueueEmpty()) {
             // helped a bit, but FINDA didn't trigger, return to the main error state
-            state = ProgressCode::ERR1DisengagingIdler;
+            state = ProgressCode::ERRDisengagingIdler;
         }
         return false;
     case ProgressCode::OK:
diff --git a/src/main.cpp b/src/main.cpp
index 38ff65f..aa8e2eb 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -207,18 +207,18 @@ void ReportVersion(const mp::RequestMsg &rq) {
 
 void ReportRunningCommand() {
     mp::ResponseMsgParamCodes commandStatus;
-    uint8_t value = 0;
+    uint16_t value = 0;
     switch (currentCommand->Error()) {
     case ErrorCode::RUNNING:
         commandStatus = mp::ResponseMsgParamCodes::Processing;
-        value = (uint8_t)currentCommand->State();
+        value = (uint16_t)currentCommand->State();
         break;
     case ErrorCode::OK:
         commandStatus = mp::ResponseMsgParamCodes::Finished;
         break;
     default:
         commandStatus = mp::ResponseMsgParamCodes::Error;
-        value = (uint8_t)currentCommand->Error();
+        value = (uint16_t)currentCommand->Error();
         break;
     }
 
diff --git a/src/modules/CMakeLists.txt b/src/modules/CMakeLists.txt
index c653a1a..3c5856c 100644
--- a/src/modules/CMakeLists.txt
+++ b/src/modules/CMakeLists.txt
@@ -9,6 +9,7 @@ target_sources(
           idler.cpp
           leds.cpp
           motion.cpp
+          movable_base.cpp
           permanent_storage.cpp
           selector.cpp
           timebase.cpp
diff --git a/src/modules/idler.cpp b/src/modules/idler.cpp
index 66b057e..9d7193d 100644
--- a/src/modules/idler.cpp
+++ b/src/modules/idler.cpp
@@ -11,57 +11,34 @@ Idler idler;
 
 namespace mm = modules::motion;
 
-Idler::EngageDisengage Idler::Disengage() {
-    if (state == Moving)
-        return EngageDisengage::Refused;
+void Idler::PrepareMoveToPlannedSlot() {
+    mm::motion.PlanMoveTo<mm::Idler>(SlotPosition(plannedSlot), 1000._I_deg_s); // @@TODO
+}
 
+Idler::OperationResult Idler::Disengage() {
+    if (state == Moving)
+        return OperationResult::Refused;
+
+    plannedSlot = IdleSlotIndex();
     plannedEngage = false;
 
     if (!Engaged())
-        return true;
+        return OperationResult::Accepted;
 
-    mm::motion.InitAxis(mm::Idler);
-    // plan move to idle position
-    mm::motion.PlanMoveTo<mm::Idler>(SlotPosition(IdleSlotIndex()), 1000._I_deg_s); // @@TODO
-    state = Moving;
-    return true;
-//        return EngageDisengage::Accepted;
-//
-//    if (!mm::motion.InitAxis(mm::Idler)) {
-//        state = Failed;
-//        return EngageDisengage::Failed;
-//    } else {
-//        // plan move to idle position
-//        mm::motion.PlanMove(mm::Idler, config::idlerSlotPositions[IdleSlotIndex()] - mm::motion.Position(mm::Idler), 1000); // @@TODO
-//        state = Moving;
-//        return EngageDisengage::Accepted;
-//    }
+    return InitMovement(mm::Idler);
 }
 
-Idler::EngageDisengage Idler::Engage(uint8_t slot) {
+Idler::OperationResult Idler::Engage(uint8_t slot) {
     if (state == Moving)
-        return EngageDisengage::Refused;
+        return OperationResult::Refused;
 
     plannedSlot = slot;
     plannedEngage = true;
 
     if (Engaged())
-        return true;
+        return OperationResult::Accepted;
 
-    mm::motion.InitAxis(mm::Idler);
-    mm::motion.PlanMoveTo<mm::Idler>(SlotPosition(slot), 1000._I_deg_s); // @@TODO
-    state = Moving;
-    return true;
-//        return EngageDisengage::Accepted;
-//
-//    if (!mm::motion.InitAxis(mm::Idler)) {
-//        state = Failed;
-//        return EngageDisengage::Failed;
-//    } else {
-//        mm::motion.PlanMove(mm::Idler, config::idlerSlotPositions[slot] - mm::motion.Position(mm::Idler), 1000); // @@TODO
-//        state = Moving;
-//        return EngageDisengage::Accepted;
-//    }
+    return InitMovement(mm::Idler);
 }
 
 bool Idler::Home() {
diff --git a/src/modules/idler.h b/src/modules/idler.h
index 78fe803..58b6042 100644
--- a/src/modules/idler.h
+++ b/src/modules/idler.h
@@ -1,6 +1,7 @@
 #pragma once
 #include "../config/config.h"
-#include "../modules/axisunit.h"
+#include "axisunit.h"
+#include "movable_base.h"
 
 namespace modules {
 
@@ -10,37 +11,21 @@ namespace idler {
 namespace mm = modules::motion;
 
 /// The Idler model handles asynchronnous Engaging / Disengaging operations and keeps track of idler's current state.
-class Idler {
+class Idler : public motion::MovableBase {
 public:
-    /// Internal states of idler's state machine
-    enum {
-        Ready = 0, // intentionally set as zero in order to allow zeroing the Idler structure upon startup -> avoid explicit initialization code
-        Moving,
-        Failed
-    };
-
     inline constexpr Idler()
-        : state(Ready)
+        : MovableBase()
         , plannedEngage(false)
-        , plannedSlot(0)
-        , currentSlot(0)
         , currentlyEngaged(false) {}
 
-    /// Engage/Disengage return values
-    enum class EngageDisengage : uint8_t {
-        Accepted, ///< the operation has been successfully started
-        Refused, ///< another operation is currently underway, cannot start a new one
-        Failed ///< the operation could not been started due to HW issues
-    };
-
     /// Plan engaging of the idler to a specific filament slot
     /// @param slot index to be activated
     /// @returns #EngageDisengage
-    EngageDisengage Engage(uint8_t slot);
+    OperationResult Engage(uint8_t slot);
 
     /// Plan disengaging of the idler, i.e. parking the idler
     /// @returns #EngageDisengage
-    EngageDisengage Disengage();
+    OperationResult Disengage();
 
     /// Plan homing of the idler axis
     /// @returns false in case an operation is already underway
@@ -55,9 +40,6 @@ public:
     /// state machines to use this call as a waiting condition for the desired state of the idler
     inline bool Engaged() const { return currentlyEngaged; }
 
-    /// @returns currently active slot
-    inline uint8_t Slot() const { return currentSlot; }
-
     /// @returns predefined positions of individual slots
     static constexpr mm::I_pos_t SlotPosition(uint8_t slot) {
         return mm::unitToAxisUnit<mm::I_pos_t>(config::idlerSlotPositions[slot]);
@@ -66,19 +48,14 @@ public:
     /// @returns the index of idle position of the idler, usually 5 in case of 0-4 valid indices of filament slots
     inline static constexpr uint8_t IdleSlotIndex() { return config::toolCount; }
 
-    /// @returns internal state of the Idler
-    inline uint8_t State() const { return state; }
+protected:
+    virtual void PrepareMoveToPlannedSlot() override;
 
 private:
-    /// internal state of the automaton
-    uint8_t state;
-
     /// direction of travel - engage/disengage
     bool plannedEngage;
-    uint8_t plannedSlot;
 
     /// current state
-    uint8_t currentSlot;
     bool currentlyEngaged;
 };
 
diff --git a/src/modules/movable_base.cpp b/src/modules/movable_base.cpp
new file mode 100644
index 0000000..8450827
--- /dev/null
+++ b/src/modules/movable_base.cpp
@@ -0,0 +1,19 @@
+#include "movable_base.h"
+#include "motion.h"
+
+namespace modules {
+namespace motion {
+
+MovableBase::OperationResult MovableBase::InitMovement(config::Axis axis) {
+    if (motion.InitAxis(axis)) {
+        PrepareMoveToPlannedSlot();
+        state = Moving;
+        return OperationResult::Accepted;
+    } else {
+        state = Failed;
+        return OperationResult::Failed;
+    }
+}
+
+} // namespace motion
+} // namespace modules
diff --git a/src/modules/movable_base.h b/src/modules/movable_base.h
new file mode 100644
index 0000000..12033ea
--- /dev/null
+++ b/src/modules/movable_base.h
@@ -0,0 +1,56 @@
+#pragma once
+#include <stdint.h>
+#include "../config/axis.h"
+
+namespace modules {
+namespace motion {
+
+/// Base class for movable modules - #Idler and #Selector contains the common code
+class MovableBase {
+public:
+    /// Internal states of the state machine
+    enum {
+        Ready = 0, // intentionally set as zero in order to allow zeroing the Idler structure upon startup -> avoid explicit initialization code
+        Moving,
+        Failed
+    };
+
+    /// Operation (Engage/Disengage/MoveToSlot) return values
+    enum class OperationResult : uint8_t {
+        Accepted, ///< the operation has been successfully started
+        Refused, ///< another operation is currently underway, cannot start a new one
+        Failed ///< the operation could not been started due to HW issues
+    };
+
+    inline constexpr MovableBase()
+        : state(Ready)
+        , plannedSlot(0)
+        , currentSlot(0) {}
+
+    /// virtual ~MovableBase(); intentionally disabled, see description in logic::CommandBase
+
+    /// @returns currently active slot
+    /// this state is updated only when a planned move is successfully finished, so it is safe for higher-level
+    /// state machines to use this call as a waiting condition for the desired state of the derive class (idler/selector)
+    inline uint8_t Slot() const { return currentSlot; }
+
+    /// @returns internal state of the state machine
+    inline uint8_t State() const { return state; }
+
+protected:
+    /// internal state of the automaton
+    uint8_t state;
+
+    /// planned slot - where to move to
+    uint8_t plannedSlot;
+
+    /// current slot
+    uint8_t currentSlot;
+
+    virtual void PrepareMoveToPlannedSlot() = 0;
+
+    OperationResult InitMovement(config::Axis axis);
+};
+
+} // namespace motion
+} // namespace modules
diff --git a/src/modules/protocol.cpp b/src/modules/protocol.cpp
index 2b60404..3acaf34 100644
--- a/src/modules/protocol.cpp
+++ b/src/modules/protocol.cpp
@@ -197,7 +197,7 @@ uint8_t Protocol::EncodeResponseVersion(const RequestMsg &msg, uint8_t value, ui
     return dst - txbuff + 1;
 }
 
-uint8_t Protocol::EncodeResponseQueryOperation(const RequestMsg &msg, ResponseMsgParamCodes code, uint8_t value, uint8_t *txbuff) {
+uint8_t Protocol::EncodeResponseQueryOperation(const RequestMsg &msg, ResponseMsgParamCodes code, uint16_t value, uint8_t *txbuff) {
     txbuff[0] = (uint8_t)msg.code;
     txbuff[1] = msg.value + '0';
     txbuff[2] = ' ';
@@ -209,10 +209,21 @@ uint8_t Protocol::EncodeResponseQueryOperation(const RequestMsg &msg, ResponseMs
         } else if (value < 100) {
             *dst++ = value / 10 + '0';
             *dst++ = value % 10 + '0';
-        } else {
+        } else if (value < 1000) {
             *dst++ = value / 100 + '0';
             *dst++ = (value / 10) % 10 + '0';
             *dst++ = value % 10 + '0';
+        } else if (value < 10000) {
+            *dst++ = value / 1000 + '0';
+            *dst++ = (value / 100) % 100 + '0';
+            *dst++ = (value / 10) % 10 + '0';
+            *dst++ = value % 10 + '0';
+        } else {
+            *dst++ = value / 10000 + '0';
+            *dst++ = (value / 1000) % 1000 + '0';
+            *dst++ = (value / 100) % 100 + '0';
+            *dst++ = (value / 10) % 10 + '0';
+            *dst++ = value % 10 + '0';
         }
     }
     *dst = '\n';
diff --git a/src/modules/protocol.h b/src/modules/protocol.h
index dea8ea1..877fedb 100644
--- a/src/modules/protocol.h
+++ b/src/modules/protocol.h
@@ -52,12 +52,12 @@ struct RequestMsg {
 struct ResponseMsg {
     RequestMsg request; ///< response is always preceeded by the request message
     ResponseMsgParamCodes paramCode; ///< code of the parameter
-    uint8_t paramValue; ///< value of the parameter
+    uint16_t paramValue; ///< value of the parameter
 
     /// @param request the source request message this response is a reply to
     /// @param paramCode code of the parameter
     /// @param paramValue value of the parameter
-    inline ResponseMsg(RequestMsg request, ResponseMsgParamCodes paramCode, uint8_t paramValue)
+    inline ResponseMsg(RequestMsg request, ResponseMsgParamCodes paramCode, uint16_t paramValue)
         : request(request)
         , paramCode(paramCode)
         , paramValue(paramValue) {}
@@ -123,7 +123,7 @@ public:
     /// @param value related to status of operation(e.g. error code or progress)
     /// @param txbuff where to format the message
     /// @returns number of bytes written into txbuff
-    static uint8_t EncodeResponseQueryOperation(const RequestMsg &msg, ResponseMsgParamCodes code, uint8_t value, uint8_t *txbuff);
+    static uint8_t EncodeResponseQueryOperation(const RequestMsg &msg, ResponseMsgParamCodes code, uint16_t value, uint8_t *txbuff);
 
     /// @returns the most recently lexed request message
     inline const RequestMsg GetRequestMsg() const { return requestMsg; }
diff --git a/src/modules/selector.cpp b/src/modules/selector.cpp
index 6ad25b1..ab2dc84 100644
--- a/src/modules/selector.cpp
+++ b/src/modules/selector.cpp
@@ -11,19 +11,20 @@ Selector selector;
 
 namespace mm = modules::motion;
 
-bool Selector::MoveToSlot(uint8_t slot) {
+void Selector::PrepareMoveToPlannedSlot() {
+    mm::motion.PlanMoveTo<mm::Selector>(SlotPosition(plannedSlot), 1000.0_S_mm_s); // @@TODO
+}
+
+Selector::OperationResult Selector::MoveToSlot(uint8_t slot) {
     if (state == Moving)
-        return false;
+        return OperationResult::Refused;
 
     plannedSlot = slot;
 
     if (currentSlot == slot)
-        return true;
+        return OperationResult::Accepted;
 
-    mm::motion.InitAxis(mm::Selector);
-    mm::motion.PlanMoveTo<mm::Selector>(SlotPosition(slot), 1000.0_S_mm_s); // @@TODO
-    state = Moving;
-    return true;
+    return InitMovement(mm::Selector);
 }
 
 bool Selector::Home() {
diff --git a/src/modules/selector.h b/src/modules/selector.h
index 8f6b347..ca867af 100644
--- a/src/modules/selector.h
+++ b/src/modules/selector.h
@@ -1,6 +1,7 @@
 #pragma once
 #include "../config/config.h"
-#include "../modules/axisunit.h"
+#include "axisunit.h"
+#include "movable_base.h"
 
 namespace modules {
 
@@ -10,24 +11,15 @@ namespace selector {
 namespace mm = modules::motion;
 
 /// The selector model - handles asynchronnous move operations between filament individual slots and keeps track of selector's current state.
-class Selector {
+class Selector : public mm::MovableBase {
 public:
-    /// Internal states of selector's state machine
-    enum {
-        Ready = 0,
-        Moving,
-        Failed
-    };
-
     inline constexpr Selector()
-        : state(Ready)
-        , plannedSlot(0)
-        , currentSlot(0) {}
+        : MovableBase() {}
 
     /// Plan move of the selector to a specific filament slot
     /// @param slot index to move to
     /// @returns false in case an operation is already underway
-    bool MoveToSlot(uint8_t slot);
+    OperationResult MoveToSlot(uint8_t slot);
 
     /// Plan homing of the selector's axis
     /// @returns false in case an operation is already underway
@@ -37,11 +29,6 @@ public:
     /// @returns true if the selector is ready to accept new commands (i.e. it has finished the last operation)
     bool Step();
 
-    /// @returns the current slot of selector
-    /// this state is updated only when a planned move is successfully finished, so it is safe for higher-level
-    /// state machines to use this call as a waiting condition for the desired state of the selector
-    inline uint8_t Slot() const { return currentSlot; }
-
     /// @returns predefined positions of individual slots
     static constexpr mm::S_pos_t SlotPosition(uint8_t slot) {
         return mm::unitToAxisUnit<mm::S_pos_t>(config::selectorSlotPositions[slot]);
@@ -50,13 +37,10 @@ public:
     /// @returns the index of idle position of the selector, usually 5 in case of 0-4 valid indices of filament slots
     inline static constexpr uint8_t IdleSlotIndex() { return config::toolCount; }
 
-private:
-    /// internal state of the automaton
-    uint8_t state;
-    uint8_t plannedSlot;
+protected:
+    virtual void PrepareMoveToPlannedSlot() override;
 
-    /// current state
-    uint8_t currentSlot;
+private:
 };
 
 /// The one and only instance of Selector in the FW
diff --git a/tests/unit/logic/cut_filament/CMakeLists.txt b/tests/unit/logic/cut_filament/CMakeLists.txt
index 7a68f82..b3b46d7 100644
--- a/tests/unit/logic/cut_filament/CMakeLists.txt
+++ b/tests/unit/logic/cut_filament/CMakeLists.txt
@@ -13,6 +13,7 @@ add_executable(
   ${CMAKE_SOURCE_DIR}/src/modules/globals.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/idler.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/leds.cpp
+  ${CMAKE_SOURCE_DIR}/src/modules/movable_base.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/permanent_storage.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/selector.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/user_input.cpp
diff --git a/tests/unit/logic/eject_filament/CMakeLists.txt b/tests/unit/logic/eject_filament/CMakeLists.txt
index eab363d..c105a92 100644
--- a/tests/unit/logic/eject_filament/CMakeLists.txt
+++ b/tests/unit/logic/eject_filament/CMakeLists.txt
@@ -13,6 +13,7 @@ add_executable(
   ${CMAKE_SOURCE_DIR}/src/modules/globals.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/idler.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/leds.cpp
+  ${CMAKE_SOURCE_DIR}/src/modules/movable_base.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/permanent_storage.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/selector.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/user_input.cpp
diff --git a/tests/unit/logic/feed_to_bondtech/CMakeLists.txt b/tests/unit/logic/feed_to_bondtech/CMakeLists.txt
index 66e312e..7558c11 100644
--- a/tests/unit/logic/feed_to_bondtech/CMakeLists.txt
+++ b/tests/unit/logic/feed_to_bondtech/CMakeLists.txt
@@ -9,6 +9,7 @@ add_executable(
   ${CMAKE_SOURCE_DIR}/src/modules/globals.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/idler.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/leds.cpp
+  ${CMAKE_SOURCE_DIR}/src/modules/movable_base.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/permanent_storage.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/selector.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/user_input.cpp
diff --git a/tests/unit/logic/feed_to_finda/CMakeLists.txt b/tests/unit/logic/feed_to_finda/CMakeLists.txt
index bd3466c..0f93766 100644
--- a/tests/unit/logic/feed_to_finda/CMakeLists.txt
+++ b/tests/unit/logic/feed_to_finda/CMakeLists.txt
@@ -9,6 +9,7 @@ add_executable(
   ${CMAKE_SOURCE_DIR}/src/modules/globals.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/idler.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/leds.cpp
+  ${CMAKE_SOURCE_DIR}/src/modules/movable_base.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/permanent_storage.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/selector.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/user_input.cpp
diff --git a/tests/unit/logic/load_filament/CMakeLists.txt b/tests/unit/logic/load_filament/CMakeLists.txt
index e8f2fb9..c435fa9 100644
--- a/tests/unit/logic/load_filament/CMakeLists.txt
+++ b/tests/unit/logic/load_filament/CMakeLists.txt
@@ -12,6 +12,7 @@ add_executable(
   ${CMAKE_SOURCE_DIR}/src/modules/globals.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/idler.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/leds.cpp
+  ${CMAKE_SOURCE_DIR}/src/modules/movable_base.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/permanent_storage.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/selector.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/user_input.cpp
diff --git a/tests/unit/logic/load_filament/test_load_filament.cpp b/tests/unit/logic/load_filament/test_load_filament.cpp
index 08091d5..a8fe2cc 100644
--- a/tests/unit/logic/load_filament/test_load_filament.cpp
+++ b/tests/unit/logic/load_filament/test_load_filament.cpp
@@ -96,11 +96,11 @@ void FailedLoadToFinda(uint8_t slot, logic::LoadFilament &lf) {
     // Stage 2 - feeding to finda
     // we'll assume the finda is defective here and does not trigger
     REQUIRE(WhileTopState(lf, ProgressCode::FeedingToFinda, 5000));
-    REQUIRE(VerifyState(lf, false, slot, slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERR1DisengagingIdler));
+    REQUIRE(VerifyState(lf, false, slot, slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERRDisengagingIdler));
 
     // Stage 3 - disengaging idler in error mode
-    REQUIRE(WhileTopState(lf, ProgressCode::ERR1DisengagingIdler, 5000));
-    REQUIRE(VerifyState(lf, false, mi::Idler::IdleSlotIndex(), slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERR1WaitingForUser));
+    REQUIRE(WhileTopState(lf, ProgressCode::ERRDisengagingIdler, 5000));
+    REQUIRE(VerifyState(lf, false, mi::Idler::IdleSlotIndex(), slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERRWaitingForUser));
 }
 
 void FailedLoadToFindaResolveHelp(uint8_t slot, logic::LoadFilament &lf) {
@@ -119,12 +119,12 @@ void FailedLoadToFindaResolveHelp(uint8_t slot, logic::LoadFilament &lf) {
         lf.Step();
     }
 
-    REQUIRE(VerifyState(lf, false, mi::Idler::IdleSlotIndex(), slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERR1EngagingIdler));
+    REQUIRE(VerifyState(lf, false, mi::Idler::IdleSlotIndex(), slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERREngagingIdler));
 
     // Stage 4 - engage the idler
-    REQUIRE(WhileTopState(lf, ProgressCode::ERR1EngagingIdler, 5000));
+    REQUIRE(WhileTopState(lf, ProgressCode::ERREngagingIdler, 5000));
 
-    REQUIRE(VerifyState(lf, false, slot, slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERR1HelpingFilament));
+    REQUIRE(VerifyState(lf, false, slot, slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERRHelpingFilament));
 }
 
 void FailedLoadToFindaResolveHelpFindaTriggered(uint8_t slot, logic::LoadFilament &lf) {
@@ -135,7 +135,7 @@ void FailedLoadToFindaResolveHelpFindaTriggered(uint8_t slot, logic::LoadFilamen
         if(step == 100){ // on 100th step make FINDA trigger
             hal::adc::SetADC(config::findaADCIndex, 1023);
         }
-        return lf.TopLevelState() == ProgressCode::ERR1HelpingFilament; },
+        return lf.TopLevelState() == ProgressCode::ERRHelpingFilament; },
         5000));
 
     REQUIRE(VerifyState(lf, false, slot, slot, true, ml::off, ml::blink0, ErrorCode::OK, ProgressCode::FeedingToBondtech));
@@ -143,9 +143,9 @@ void FailedLoadToFindaResolveHelpFindaTriggered(uint8_t slot, logic::LoadFilamen
 
 void FailedLoadToFindaResolveHelpFindaDidntTrigger(uint8_t slot, logic::LoadFilament &lf) {
     // Stage 5 - move the pulley a bit - no FINDA change
-    REQUIRE(WhileTopState(lf, ProgressCode::ERR1HelpingFilament, 5000));
+    REQUIRE(WhileTopState(lf, ProgressCode::ERRHelpingFilament, 5000));
 
-    REQUIRE(VerifyState(lf, false, slot, slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERR1DisengagingIdler));
+    REQUIRE(VerifyState(lf, false, slot, slot, false, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_ON, ProgressCode::ERRDisengagingIdler));
 }
 
 TEST_CASE("load_filament::failed_load_to_finda_0-4_resolve_help_second_ok", "[load_filament]") {
diff --git a/tests/unit/logic/tool_change/CMakeLists.txt b/tests/unit/logic/tool_change/CMakeLists.txt
index 1b38c07..d965ec7 100644
--- a/tests/unit/logic/tool_change/CMakeLists.txt
+++ b/tests/unit/logic/tool_change/CMakeLists.txt
@@ -15,6 +15,7 @@ add_executable(
   ${CMAKE_SOURCE_DIR}/src/modules/globals.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/idler.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/leds.cpp
+  ${CMAKE_SOURCE_DIR}/src/modules/movable_base.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/permanent_storage.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/selector.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/user_input.cpp
diff --git a/tests/unit/logic/unload_filament/CMakeLists.txt b/tests/unit/logic/unload_filament/CMakeLists.txt
index b3d0672..7f4b1da 100644
--- a/tests/unit/logic/unload_filament/CMakeLists.txt
+++ b/tests/unit/logic/unload_filament/CMakeLists.txt
@@ -12,6 +12,7 @@ add_executable(
   ${CMAKE_SOURCE_DIR}/src/modules/globals.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/idler.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/leds.cpp
+  ${CMAKE_SOURCE_DIR}/src/modules/movable_base.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/permanent_storage.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/selector.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/user_input.cpp
diff --git a/tests/unit/logic/unload_filament/test_unload_filament.cpp b/tests/unit/logic/unload_filament/test_unload_filament.cpp
index f81aaa8..5d02745 100644
--- a/tests/unit/logic/unload_filament/test_unload_filament.cpp
+++ b/tests/unit/logic/unload_filament/test_unload_filament.cpp
@@ -158,10 +158,10 @@ void FindaDidntTriggerCommonSetup(uint8_t slot, logic::UnloadFilament &uf) {
     // no change in selector's position
     // FINDA still on
     // red LED should blink, green LED should be off
-    REQUIRE(VerifyState(uf, true, slot, slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERR1DisengagingIdler));
+    REQUIRE(VerifyState(uf, true, slot, slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERRDisengagingIdler));
 
     // Stage 2 - idler should get disengaged
-    REQUIRE(WhileTopState(uf, ProgressCode::ERR1DisengagingIdler, 5000));
+    REQUIRE(WhileTopState(uf, ProgressCode::ERRDisengagingIdler, 5000));
 
     // we still think we have filament loaded at this stage
     // idler should have been disengaged
@@ -169,7 +169,7 @@ void FindaDidntTriggerCommonSetup(uint8_t slot, logic::UnloadFilament &uf) {
     // FINDA still on
     // red LED should blink
     // green LED should be off
-    REQUIRE(VerifyState(uf, true, mi::Idler::IdleSlotIndex(), slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERR1WaitingForUser));
+    REQUIRE(VerifyState(uf, true, mi::Idler::IdleSlotIndex(), slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERRWaitingForUser));
 }
 
 void FindaDidntTriggerResolveHelp(uint8_t slot, logic::UnloadFilament &uf) {
@@ -194,17 +194,17 @@ void FindaDidntTriggerResolveHelp(uint8_t slot, logic::UnloadFilament &uf) {
     // no change in selector's position
     // FINDA still on
     // red LED should blink, green LED should be off
-    REQUIRE(VerifyState(uf, true, mi::Idler::IdleSlotIndex(), slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERR1EngagingIdler));
+    REQUIRE(VerifyState(uf, true, mi::Idler::IdleSlotIndex(), slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERREngagingIdler));
 
     // Stage 4 - engage the idler
-    REQUIRE(WhileTopState(uf, ProgressCode::ERR1EngagingIdler, 5000));
+    REQUIRE(WhileTopState(uf, ProgressCode::ERREngagingIdler, 5000));
 
     // we still think we have filament loaded at this stage
     // idler should be engaged
     // no change in selector's position
     // FINDA still on
     // red LED should blink, green LED should be off
-    REQUIRE(VerifyState(uf, true, slot, slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERR1HelpingFilament));
+    REQUIRE(VerifyState(uf, true, slot, slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERRHelpingFilament));
 }
 
 void FindaDidntTriggerResolveHelpFindaTriggered(uint8_t slot, logic::UnloadFilament &uf) {
@@ -215,7 +215,7 @@ void FindaDidntTriggerResolveHelpFindaTriggered(uint8_t slot, logic::UnloadFilam
         if(step == 100){ // on 100th step make FINDA trigger
             hal::adc::SetADC(config::findaADCIndex, 0);
         }
-        return uf.TopLevelState() == ProgressCode::ERR1HelpingFilament; },
+        return uf.TopLevelState() == ProgressCode::ERRHelpingFilament; },
         5000));
 
     // we still think we have filament loaded at this stage
@@ -228,14 +228,14 @@ void FindaDidntTriggerResolveHelpFindaTriggered(uint8_t slot, logic::UnloadFilam
 
 void FindaDidntTriggerResolveHelpFindaDidntTrigger(uint8_t slot, logic::UnloadFilament &uf) {
     // Stage 5 - move the pulley a bit - no FINDA change
-    REQUIRE(WhileTopState(uf, ProgressCode::ERR1HelpingFilament, 5000));
+    REQUIRE(WhileTopState(uf, ProgressCode::ERRHelpingFilament, 5000));
 
     // we still think we have filament loaded at this stage
     // idler should be engaged
     // no change in selector's position
     // FINDA still pressed
     // red LED should blink, green LED should be off
-    REQUIRE(VerifyState(uf, true, slot, slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERR1DisengagingIdler));
+    REQUIRE(VerifyState(uf, true, slot, slot, true, ml::off, ml::blink0, ErrorCode::FINDA_DIDNT_SWITCH_OFF, ProgressCode::ERRDisengagingIdler));
 }
 
 TEST_CASE("unload_filament::finda_didnt_trigger_resolve_help_second_ok", "[unload_filament]") {
diff --git a/tests/unit/logic/unload_to_finda/CMakeLists.txt b/tests/unit/logic/unload_to_finda/CMakeLists.txt
index 33c2f87..33ace3b 100644
--- a/tests/unit/logic/unload_to_finda/CMakeLists.txt
+++ b/tests/unit/logic/unload_to_finda/CMakeLists.txt
@@ -9,6 +9,7 @@ add_executable(
   ${CMAKE_SOURCE_DIR}/src/modules/globals.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/idler.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/leds.cpp
+  ${CMAKE_SOURCE_DIR}/src/modules/movable_base.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/permanent_storage.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/selector.cpp
   ${CMAKE_SOURCE_DIR}/src/modules/user_input.cpp