fix(api): fix for backwards liquid probe when using aspirate_while_probing (#19027)

caila-marashaj · web-flow · commit 1beb34ccad61 · 2025-07-24T17:14:01.000-04:00
diff --git a/api/src/opentrons/hardware_control/ot3api.py b/api/src/opentrons/hardware_control/ot3api.py
@@ -2835,7 +2835,7 @@ async def liquid_probe(  # noqa: C901
         if not probe_settings:
             probe_settings = deepcopy(self.config.liquid_sense)
 
-        # We need to significatly slow down the 96 channel liquid probe
+        # We need to significantly slow down the 96 channel liquid probe
         if self.gantry_load in [
             GantryLoad.HIGH_THROUGHPUT_1000,
             GantryLoad.HIGH_THROUGHPUT_200,
diff --git a/hardware/opentrons_hardware/hardware_control/tool_sensors.py b/hardware/opentrons_hardware/hardware_control/tool_sensors.py
@@ -300,7 +300,7 @@ async def liquid_probe(
     )
     p_prep_distance = float(plunger_impulse_time * plunger_speed)
     p_pass_distance = float(max_p_distance - p_prep_distance)
-    max_z_distance = (p_pass_distance / plunger_speed) * mount_speed
+    max_z_distance = (p_pass_distance / abs(plunger_speed)) * mount_speed
 
     lower_plunger = create_step(
         distance={tool: float64(p_prep_distance)},

Original file line number	Diff line number	Diff line change
`@@ -300,7 +300,7 @@ async def liquid_probe(`
`300`	`300`	`)`
`301`	`301`	`p_prep_distance = float(plunger_impulse_time * plunger_speed)`
`302`	`302`	`p_pass_distance = float(max_p_distance - p_prep_distance)`
`303`		`- max_z_distance = (p_pass_distance / plunger_speed) * mount_speed`
	`303`	`+ max_z_distance = (p_pass_distance / abs(plunger_speed)) * mount_speed`
`304`	`304`
`305`	`305`	`lower_plunger = create_step(`
`306`	`306`	`distance={tool: float64(p_prep_distance)},`