Reset plotter state and remove old HDF5 file for new acquisitions

2 files changed, 15 insertions, 1 deletions

diff --git a/picostream/dfplot.py b/picostream/dfplot.py
index 89784ac..63ffe33 100644
--- a/picostream/dfplot.py
+++ b/picostream/dfplot.py
@@ -286,6 +286,7 @@ class HDF5LivePlotter(QWidget):
         # Reset rate calculation to avoid confusion
         self.rate_check_start_time = None
         self.rate_check_start_samples = 0
+        self.last_displayed_size = 0
 
     def _handle_stale_data(self) -> None:
         """Handle a file check where no new data is found."""
diff --git a/picostream/main.py b/picostream/main.py
index b40c2c1..f1504fb 100644
--- a/picostream/main.py
+++ b/picostream/main.py
@@ -1,5 +1,6 @@
 
 
+import os
 import sys
 from typing import Any, Dict, Optional
 
@@ -162,11 +163,23 @@ class PicoStreamMainWindow(QMainWindow):
         self.start_button.setEnabled(False)
         self.stop_button.setEnabled(True)
 
+        output_file = self.output_file_input.text()
+
+        # Reset plotter state and ensure a clean file for the new acquisition.
+        self.plotter.set_hdf5_path(output_file)
+        if os.path.exists(output_file):
+            try:
+                os.remove(output_file)
+            except OSError as e:
+                self.on_acquisition_error(f"Failed to remove old file: {e}")
+                self.on_acquisition_finished()  # Reset UI state
+                return
+
         settings = {
             "sample_rate_msps": self.sample_rate_input.value(),
             "resolution_bits": int(self.resolution_input.currentText()),
             "channel_range_str": self.voltage_range_input.currentText(),
-            "output_file": self.output_file_input.text(),
+            "output_file": output_file,
             "hardware_downsample": self.hw_downsample_input.value(),
             "downsample_mode": self.downsample_mode_input.currentText(),
             "offset_v": self.offset_v_input.value(),