Add option --require-all-thermistors

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Next version
 
+### 🚀 New
+
+* Add option `--require-all-thermistors`. When passed, the thermistors don't close the valve when they become active. Once all thermistors are active, the valves are all closed at the same time. This can potentially prevent overpressures in the last one or two cryostat being filled as the other valves close.
+
 ### ✨ Improved
 
 * Improve handling of keyboard interrupt during post-processing.

src/lvmcryo/__main__.py

@@ -157,10 +157,22 @@ async def ln2(
         bool,
         Option(
             " /--no-use-thermistors",
+            envvar="LVMCRYO_USE_THERMISTORS",
             help="Use thermistor values to determine purge/fill time.",
             rich_help_panel="Purge and fill options",
         ),
     ] = True,
+    require_all_thermistors: Annotated[
+        bool,
+        Option(
+            "--require-all-thermistors",
+            envvar="LVMCRYO_REQUIRE_ALL_THERMISTORS",
+            help="If set, waits until all thermistors have activated before closing "
+            "any of the valves. This prevents overpressures in the cryostats when only"
+            "some of the valves are open. Ignore if --no-use-thermistors is used. ",
+            rich_help_panel="Purge and fill options",
+        ),
+    ] = False,
     check_pressures: Annotated[
         bool,
         Option(
@@ -421,6 +433,7 @@ async def ln2(
             email=email,
             email_level=email_level,
             use_thermistors=use_thermistors,
+            require_all_thermistors=require_all_thermistors,
             check_pressures=check_pressures,
             check_temperatures=check_temperatures,
             max_pressure=max_pressure,

src/lvmcryo/config.py

@@ -106,6 +106,7 @@ class Config(BaseModel):
     dry_run: bool = False
 
     use_thermistors: bool = True
+    require_all_thermistors: bool=False
     check_pressures: bool = True
     check_temperatures: bool = True
     max_pressure: float | None = None

src/lvmcryo/handlers/ln2.py

@@ -25,6 +25,7 @@
 
 from lvmopstools.devices.specs import spectrograph_pressures, spectrograph_temperatures
 from lvmopstools.devices.thermistors import read_thermistors
+from sdsstools.utils import GatheringTaskGroup
 
 from lvmcryo.config import ValveConfig, get_internal_config
 from lvmcryo.handlers.thermistor import ThermistorMonitor
@@ -347,6 +348,7 @@ async def fill(
         self,
         cameras: list[str] | None = None,
         use_thermistors: bool = True,
+        require_all_thermistors: bool = False,
         min_fill_time: float | None = None,
         max_fill_time: float | None = None,
         prompt: bool | None = None,
@@ -360,6 +362,9 @@ async def fill(
             used to instantiate the `.LN2Handler` instance.
         use_thermistors
             Whether to use the thermistors to close the valves.
+        require_all_thermistors
+            Whether to require all thermistors to be active before closing the
+            valves. If `False`, valves as closed as their thermistors become active.
         min_fill_time
             The minimum time to keep the fill valves open. Only relevant if
             using the thermistors.
@@ -391,6 +396,7 @@ async def fill(
                     min_open_time=min_fill_time or 0.0,
                     max_open_time=max_fill_time,
                     use_thermistor=use_thermistors,
+                    close_on_active=not require_all_thermistors,
                 )
             )
 
@@ -417,6 +423,14 @@ async def fill(
             raise
 
         finally:
+            if use_thermistors and require_all_thermistors:
+                # If we are waiting for all thermistors to be active,
+                # we need to close all valves now.
+                self.log.info("Closing all valves.")
+                async with GatheringTaskGroup() as group:
+                    for valve_handler in self.valve_handlers.values():
+                        group.create_task(valve_handler._set_state(False))
+
             self.event_times.fill_complete = get_now()
             if prompt:
                 sshkeyboard.stop_listening()

src/lvmcryo/handlers/thermistor.py

@@ -130,6 +130,8 @@ def __post_init__(self):
         self.log = self.valve_handler.log
 
         self.thermistor_monitor = ThermistorMonitor(interval=self.monitoring_interval)
+
+        self.active: bool = False
         self.first_active: datetime | None = None
 
     async def start_monitoring(self):
@@ -262,10 +264,17 @@ async def start_monitoring(self):
             f"Thermistor {self.channel!r} has been active for more than "
             f"{elapsed_active:.1f} seconds."
         )
+        self.active = True
 
         if self.close_valve:
             self.valve_handler.log.debug(
                 f"Closing valve {self.valve_handler.valve!r} "
                 "due to thermistor feedback."
             )
-            await self.valve_handler.finish()
+        else:
+            self.valve_handler.log.warning(
+                f"Thermistor {self.channel!r} is active. Calling "
+                "ValveHandler.finish() but not closing the valve."
+            )
+
+        await self.valve_handler.finish(close_valve=self.close_valve)

src/lvmcryo/handlers/valve.py

@@ -224,6 +224,7 @@ async def start_fill(
         min_open_time: float = 0.0,
         max_open_time: float | None = None,
         use_thermistor: bool = True,
+        close_on_active: bool = True,
     ):
         """Starts a fill.
 
@@ -238,6 +239,9 @@ async def start_fill(
             Whether to use the thermistor to close the valve. If ``True`` and
             ``fill_time`` is not ``None``, ``fill_time`` become the maximum
             open time.
+        close_on_active
+            If ``use_thermistor=True``, closes the valve when the thermistor becomes
+            active. Otherwise just blocks while the thermistor is inactive.
 
         """
 
@@ -260,6 +264,7 @@ async def start_fill(
             self.thermistor = ThermistorHandler(
                 self,
                 channel=thermistor_channel,
+                close_valve=close_on_active,
                 **self.thermistor_info,
             )
             self.thermistor.min_open_time = min_open_time
@@ -294,10 +299,11 @@ async def _schedule_timeout(self, timeout: float):
         await asyncio.sleep(timeout)
         await self.finish(did_timeout=True)
 
-    async def finish(self, did_timeout: bool = False):
+    async def finish(self, close_valve: bool = True, did_timeout: bool = False):
         """Finishes the fill, closing the valve."""
 
-        await self._set_state(False, did_timeout=did_timeout)
+        if close_valve:
+            await self._set_state(False, did_timeout=did_timeout)
 
         self._monitor_task = await cancel_task(self._monitor_task)
         self._timeout_task = await cancel_task(self._timeout_task)

src/lvmcryo/runner.py

@@ -134,6 +134,7 @@ async def ln2_runner(
         max_fill_time = config.fill_time or config.max_fill_time
         await handler.fill(
             use_thermistors=config.use_thermistors,
+            require_all_thermistors=config.require_all_thermistors,
             min_fill_time=config.min_fill_time,
             max_fill_time=max_fill_time,
             prompt=not config.no_prompt,