Environment Manager

Page Sections:

• Hardware Config
• Parameter Config
• Drying Data Setup
• MMU_HEATER Command
• Single-Heater Mode Operation
• Per-Gate Heater Mode Operation
  • Power Management Queue
  • Per-Gate Cancellation
  • Raw Per-Gate Heater Control
• Venting Macro
• Spool Rotation
• Status Variables
• Troubleshooting

Happy Hare includes an MMU Environment Manager that can control one heater (shared enclosure) or multiple heaters (one per gate) and provides a managed filament drying cycle. Drying can terminate on time or (if the sensor supports it) humidity. During drying the manager can optionally call a venting macro and, if an eSpooler is fitted, periodically rotate spools.

Hardware Config

Two setups are supported:

1. Single-heater / shared enclosure
   A single heater warms a shared chamber; a single environment sensor provides temperature (and optionally humidity).

2. Per-gate heaters (e.g. EMU design)
   Each gate has its own heater and environment sensor. A basic “power management” queue limits the number of simultaneously active heaters.

mmu_hardware.cfg

1) Single-heater mode (typical)

Configure a heater and an environment sensor:

# Example names only - use your actual configured objects
filament_heater: heater_generic mmu_heater
environment_sensor: temperature_sensor mmu_environment

2) Per-gate heater mode

Configure a list of heaters and sensors, one per gate, plus a concurrency limit:

# One entry per gate. Empty entries may be left blank if a gate has no heater/sensor.
filament_heaters: heater_generic mmu_heater_0, heater_generic mmu_heater_1, heater_generic mmu_heater_2, heater_generic mmu_heater_3
environment_sensors: temperature_sensor env_0, temperature_sensor env_1, temperature_sensor env_2, temperature_sensor env_3

# Limit the number of simultaneously active heaters (power/PSU protection)
max_concurrent_heaters: 2

Note

• Per-gate mode requires both filament_heaters and environment_sensors to be present. If either list is missing, the manager uses single-heater mode.

Parameter Config

mmu_parameters.cfg

The manager uses the following parameters. Defaults are generally good starting points.

# Filament dryer defaults ----------------------------------------------------------------------------------------------
heater_default_dry_temp: 45          # °C default drying temperature
heater_default_dry_time: 300         # minutes default drying time
heater_default_humidity: 10          # %RH stop early if humidity <= this target (if sensor supports humidity)

# Optional venting macro ------------------------------------------------------------------------------------------------
heater_vent_macro:                   # macro name / gcode to run periodically during drying (blank disables)
heater_vent_interval: 0              # minutes. 0 disables venting

# Optional spool rotation (eSpooler) ------------------------------------------------------------------------------------
heater_rotate_interval: 5            # minutes between rotation attempts (min 1)

Tip

• Most of these parameters are safe to tune without changing wiring/hardware.
• Venting and rotation are only active during a drying cycle.

Drying Data Setup

The drying_data table defines recommended temperature and time per material. Keys are treated case-insensitively (internally normalized to uppercase).

Example drying_data

drying_data: "{'PLA': (45, 240), 'PETG': (55, 300), 'NYLON': (65, 480)}"

• Values are (temperature_C, time_minutes)
• Missing materials fall back to heater_default_dry_temp and heater_default_dry_time

To print the configured table at runtime:

MMU_HEATER DRYING_DATA=1

MMU_HEATER Command

The MMU_HEATER command controls heater(s) and manages drying cycles.

Syntax

MMU_HEATER [HELP=1]
           [DRYING_DATA=1]
           [STOP=1]
           [DRY=1]
           [TEMP=<degreesC>]
           [TIMER=<minutes>]
           [HUMIDITY=<percent>]
           [GATES=x,y]
           [VENT_INTERVAL=<minutes>]
           [ROTATE=0|1]

Parameters

• STOP – Stop drying and turn off heater(s). In per-gate mode, GATES= cancels only those gates.
• DRY – Start a drying cycle.
• TEMP – Override temperature for a cycle, or set raw heater temperature (no managed cycle).
• TIMER – Override drying time.
• HUMIDITY – End the drying cycle early once humidity <= target (if sensor supports humidity).
• GATES – In per-gate mode selects which gates to control or dry. Required for ROTATE=1.
• VENT_INTERVAL – Override the configured vent interval for this drying cycle.
• ROTATE – Enable periodic eSpooler rotation during drying (if eSpooler is fitted).

Status report

Calling MMU_HEATER with no parameters prints a status report (drying state, temps/humidity, per-gate state in per-gate mode, venting/rotation state when applicable).

Single-Heater Mode Operation

Single-heater mode is used when filament_heater + environment_sensor are configured (and per-gate lists are not).

Start a drying cycle

MMU_HEATER DRY=1

• If TEMP is not specified, the manager selects a recommended temperature/time from drying_data based on current gate materials.
• Recommended behavior is typically: lowest safe temp across selected materials, and longest time across selected materials.

Override defaults:

MMU_HEATER DRY=1 TEMP=50 TIMER=240 HUMIDITY=12

Stop a drying cycle

MMU_HEATER STOP=1

Early termination (humidity)

If the configured environment sensor supports humidity, drying can end early once humidity <= HUMIDITY.

Per-Gate Heater Mode Operation

Per-gate mode is used when both filament_heaters and environment_sensors lists are configured.

Start a per-gate drying cycle

MMU_HEATER DRY=1 GATES=0,2,3

• Each gate uses its own recommended temperature/time from drying_data unless overridden.
• If TEMP is specified, it overrides temperatures for all selected gates.
• Each gate monitors humidity from its own environment sensor (if available).

Gate selection default

If GATES is not supplied, the manager defaults to all non-empty gates.

Note

• When using ROTATE=1, you must explicitly supply GATES=.

Power Management Queue

If max_concurrent_heaters is less than the number of gates being dried, the manager:

• Starts drying on up to max_concurrent_heaters gates
• Queues remaining gates
• Starts the next queued gate when an active gate completes

This means the total wall-clock time may be longer than a single-gate timer.

Per-Gate Cancellation

To cancel only specific gates during an active per-gate cycle:

MMU_HEATER STOP=1 GATES=1,3

• Active gates: heater turned off immediately and marked done
• Queued gates: removed from queue and marked done

If all selected gates are completed/cancelled, the overall cycle ends automatically.

Raw Per-Gate Heater Control

To directly set per-gate heater targets (not a managed drying cycle):

MMU_HEATER TEMP=45 GATES=0,1

Behavior when a managed cycle is running:

• If a gate is queued, only the target is updated; the heater is not turned on until the gate becomes active.
• If a gate is active, the heater is updated immediately.
• If a gate is not part of the current cycle, it is set immediately.

Venting Macro

Venting is optional and runs only during a drying cycle.

Enable by setting:

• heater_vent_macro
• heater_vent_interval > 0

Or override for a single run:

MMU_HEATER DRY=1 VENT_INTERVAL=10

Behavior:

• Single-heater mode: macro runs with no args
• Per-gate mode: macro runs with GATES=<currently active gates>

Spool Rotation

The manager can optionally rotate spools during drying if an eSpooler is fitted and the cycle is started with ROTATE=1.

Enabling rotation

MMU_HEATER DRY=1 ROTATE=1 GATES=1,3

Rules:

• GATES= must be explicitly provided when ROTATE=1
• On start, the manager warns if any specified gates are not EMPTY (drying still proceeds)
• Every heater_rotate_interval minutes, the manager:
  • re-checks the current gate status
  • rotates only gates that are EMPTY at that moment (supports dynamic transitions to EMPTY)

Important

Filament must be removed from the MMU inlet and fastened to the spool. Rotation is only safe when the gate is EMPTY.

Status Variables

The manager exports structured status values for UI/clients:

• drying_cycle – boolean: in drying cycle or not
• drying_per_gate – boolean: true if per-gate heaters are configured
• drying_active_gates – list[int]: gates currently active (heaters on)
• drying_pending_gates – list[int]: gates queued
• drying_completed_gates – list[int]: completed/cancelled gates

Troubleshooting

Humidity is always missing / None

• The environment sensor may not support humidity, or humidity chip object may not be present.
• Drying will still run using time, but humidity early-termination will not occur.

Venting does not run

• heater_vent_macro is blank, or heater_vent_interval is 0.
• If venting is enabled, check logs for macro errors.

Drying takes longer than expected in per-gate mode

• Gates may be queued due to max_concurrent_heaters.
• Total time = sum of per-gate timers when fully serialized by the queue.

Rotation does not occur

• eSpooler not fitted (has_espooler() false), or
• ROTATE=1 not used, or
• gates were not EMPTY at rotation tick (rotation only applies to EMPTY gates).