From b0c007409285d5ede0e5cf14cb4aea1890fb233a Mon Sep 17 00:00:00 2001
From: narno2202 <130909513+narno2202@users.noreply.github.com>
Date: Sun, 17 Aug 2025 01:21:27 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=94=A7=20Support=20EXTRUDERS=200=20with?=
 =?UTF-8?q?=20FT=5FMOTION=20(#27984)?=
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---
 Marlin/src/module/ft_motion.cpp | 14 ++++++++------
 Marlin/src/module/ft_motion.h   |  2 +-
 buildroot/tests/rambo           |  4 ++--
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/Marlin/src/module/ft_motion.cpp b/Marlin/src/module/ft_motion.cpp
index 5ccc364c1d..1cc90776d6 100644
--- a/Marlin/src/module/ft_motion.cpp
+++ b/Marlin/src/module/ft_motion.cpp
@@ -91,7 +91,7 @@ uint32_t FTMotion::interpIdx = 0;               // Index of current data point b
 
 #if ENABLED(DISTINCT_E_FACTORS)
   uint8_t FTMotion::block_extruder_axis;        // Cached E Axis from last-fetched block
-#else
+#elif HAS_EXTRUDERS
   constexpr uint8_t FTMotion::block_extruder_axis;
 #endif
 
@@ -400,7 +400,7 @@ void FTMotion::reset() {
     shaping.zi_idx = 0;
   #endif
 
-  TERN_(HAS_EXTRUDERS, e_raw_z1 = e_advanced_z1 = 0.0f);
+  TERN_(HAS_EXTRUDERS, e_raw_z1 = e_advanced_z1 = 0.0f);  // Reset linear advance variables.
   TERN_(DISTINCT_E_FACTORS, block_extruder_axis = E_AXIS);
 
   axis_move_end_ti.reset();
@@ -582,25 +582,27 @@ void FTMotion::loadBlockData(block_t * const current_block) {
 // Generate data points of the trajectory.
 void FTMotion::makeVector() {
   do {
-    float accel_k = 0.0f;                                 // (mm/s^2) Acceleration K factor
     float tau = (makeVector_idx + 1) * (FTM_TS);          // (s) Time since start of block
     float dist = 0.0f;                                    // (mm) Distance traveled
+    #if HAS_EXTRUDERS
+      float accel_k = 0.0f;                               // (mm/s^2) Acceleration K factor
+    #endif
 
     if (makeVector_idx < N1) {
       // Acceleration phase
       dist = (f_s * tau) + (0.5f * accel_P * sq(tau));    // (mm) Distance traveled for acceleration phase since start of block
-      accel_k = accel_P;                                  // (mm/s^2) Acceleration K factor from Accel phase
+      TERN_(HAS_EXTRUDERS, accel_k = accel_P);            // (mm/s^2) Acceleration K factor from Accel phase
     }
     else if (makeVector_idx < (N1 + N2)) {
       // Coasting phase
       dist = s_1e + F_P * (tau - N1 * (FTM_TS));          // (mm) Distance traveled for coasting phase since start of block
-      //accel_k = 0.0f;
+      //TERN_(HAS_EXTRUDERS, accel_k = 0.0f);
     }
     else {
       // Deceleration phase
       tau -= (N1 + N2) * (FTM_TS);                        // (s) Time since start of decel phase
       dist = s_2e + F_P * tau + 0.5f * decel_P * sq(tau); // (mm) Distance traveled for deceleration phase since start of block
-      accel_k = decel_P;                                  // (mm/s^2) Acceleration K factor from Decel phase
+      TERN_(HAS_EXTRUDERS, accel_k = decel_P);            // (mm/s^2) Acceleration K factor from Decel phase
     }
 
     #define _SET_TRAJ(q) traj.q[makeVector_batchIdx] = startPosn.q + ratio.q * dist;
diff --git a/Marlin/src/module/ft_motion.h b/Marlin/src/module/ft_motion.h
index 4cf8017083..feaea55ca1 100644
--- a/Marlin/src/module/ft_motion.h
+++ b/Marlin/src/module/ft_motion.h
@@ -171,7 +171,7 @@ class FTMotion {
 
     #if ENABLED(DISTINCT_E_FACTORS)
       static uint8_t block_extruder_axis;  // Cached extruder axis index
-    #else
+    #elif HAS_EXTRUDERS
       static constexpr uint8_t block_extruder_axis = E_AXIS;
     #endif
 
diff --git a/buildroot/tests/rambo b/buildroot/tests/rambo
index 13a8e1e719..3198c71cf3 100755
--- a/buildroot/tests/rambo
+++ b/buildroot/tests/rambo
@@ -71,8 +71,8 @@ opt_set MOTHERBOARD BOARD_RAMBO EXTRUDERS 0 TEMP_SENSOR_BED 1 TEMP_SENSOR_PROBE
         DEFAULT_MAX_ACCELERATION '{ 3000, 3000, 100 }' \
         MANUAL_FEEDRATE '{ 50*60, 50*60, 4*60 }' \
         AXIS_RELATIVE_MODES '{ false, false, false }'
-opt_enable REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER FIX_MOUNTED_PROBE Z_SAFE_HOMING
-exec_test $1 $2 "Rambo heated bed only" "$3"
+opt_enable REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER FIX_MOUNTED_PROBE Z_SAFE_HOMING FT_MOTION
+exec_test $1 $2 "Rambo with ZERO EXTRUDERS, heated bed, FT_MOTION" "$3"
 
 #
 # Rambo with MMU2