Dell SC200
fan control & monitoring.

Control enclosure fans from Linux using temperature curves. Manage multiple enclosures with one daemon, discover serial devices, and monitor cooling in Grafana.

Install sc200

curl -fsSL https://sc200.merkulov.me/install.sh | sudo bash

Linux amd64 or arm64 with systemd. Requires curl, GNU tar, sha256sum, and standard account-management tools.

Read the installer · Download releases

Prometheus metrics. Grafana dashboard.

Track sensor temperatures, measured fan RPM, requested fan speeds, telemetry freshness, and fallback status per enclosure. Scrape /metrics on port 9700 and import the included dashboard.

Grafana dashboard showing healthy enclosure status, fresh telemetry, sensor temperatures, measured fan speeds, fan control percentages, and fallback status. — Get the Grafana dashboard · Monitoring setup

Discover your enclosures

Interactive setup finds supported enclosures and writes their serial paths and sensor indices. To preview configuration for a known port, stop the daemon and run:

sudo sc200 discover --port /dev/ttyS0 --profile safe

Add --write to save new devices. Existing enclosure settings are preserved. Prefer stable /dev/serial/by-id/… paths when available.

Choose a starting profile

SafeQuietShaded range: both profiles at 100%

Safe: The default: a 20% minimum, a curve from 20% at 25°C to 100% at 45°C, and 100% fallback speed.
Quiet: A 10% minimum, a curve from 10% at 25°C to 20% at 45°C, and 15% fallback speed. Select with --profile quiet.

Both profiles request 100% at the 45°C critical threshold. Profiles generate editable YAML for new devices; tune the values and verify temperatures under sustained load.

Configuration

Edit /etc/sc200/config.yaml and restart the service to apply changes. Defaults below match the Safe profile; Quiet changes min_speed, safe_speed, and curve. In YAML, temperatures and percentages are numbers without unit suffixes; durations use strings such as 10s.

Global settings
Field	Default	Purpose
`dry_run`	false	Read telemetry and log control decisions without writing fan speeds.
`http.listen`	127.0.0.1:9700	Bind address for Prometheus metrics and health endpoints. Keep loopback unless network access is restricted; endpoints have no authentication.
`shutdown_timeout`	5s	Cleanup deadline supplied to the HTTP server and service manager; serial cleanup can take longer.
`enclosures`	Required	List of independently controlled enclosures. At least one must be enabled.

Per-enclosure settings · under enclosures[]
Field	Default	Purpose
`id`	Required	Unique enclosure identifier used in logs, health responses, and metric labels.
`enabled`	true	Enable control for this enclosure. Disabled entries are still validated.
`port`	Required	Absolute serial-device path. Prefer a stable /dev/serial/by-id/… path.
`baud`	38400	Serial baud rate; must match the enclosure console.
`poll_interval`	10s	Normal delay between telemetry and control iterations.
`command_timeout`	2s	Time budget for a serial operation. Must be shorter than poll_interval.
`stale_after`	30s	Telemetry age that triggers fallback and reconnection. Must exceed poll_interval + command_timeout.
`refresh_interval`	30s	Resend the current fan target after this interval, even if unchanged.
`reconnect_min`	1s	Initial retry delay after a connection or control failure.
`reconnect_max`	30s	Maximum retry delay; retries double from reconnect_min up to this limit.
`recovery_samples`	3	Consecutive valid samples required to recover healthy control. Uses safe_speed during recovery.
`min_speed`	20%	Minimum normal fan target. Curve points and safe_speed must be at least this value.
`safe_speed`	100%	Fallback requested on startup, recovery, telemetry faults, or control errors when communication permits.
`critical_temperature`	45°C	Any installed, available sensor at this threshold requests 100% fan speed, including sensors outside required_sensors.
`hysteresis`	2°C	Temperature margin applied when evaluating speed reductions. Increases use the current temperature.
`cooldown`	30s	How long an eligible lower target must stay stable before reducing speed. Increases and emergencies do not wait.
`required_sensors`	Auto	Sensor indices used for normal control, taking the hottest reading. If omitted, remembers all initially installed sensors. Discovery writes explicit indices.
`curve`	Safe profile	Ordered temperature/speed points, interpolated linearly and rounded up. At least two points; temperatures increase and speeds cannot decrease.
`curve[].temperature`	25, 30, 35, 40, 45°C	Temperature at each curve point. Fractional values are allowed.
`curve[].speed`	20, 30, 50, 75, 100%	Requested fan percentage at each curve point, from min_speed to 100.

Full configuration reference and validation rules