scietex.vfd_service

Scietex microservice daemon for variable frequency drive (VFD) monitoring and control.

The service drives one or more VFDs through the Scietex Modbus gateway. Each drive is handled by a driver from scietex.hal.vfd, selected by entry point name in the service configuration. The service polls each drive on its own long-lived task, publishes readings to a per-drive Valkey stream, and exposes control tasks (vfd:start, vfd:stop, vfd:set-frequency, vfd:clear-error) on the data lane.

Supported drives

The gateway descriptors (intek_spe_b, vesper_e5_8200, vesper_e4_8400) live under the scietex.modbus.drivers group and are registered with the gateway, not with this service. The _modbus suffix distinguishes the HAL driver entry points from the gateway descriptors.

Configuration

The service reads vfd/vfd.yml under the framework config directory (SCIETEX_CONFIG_DIR, default /config in the container). The file is created with defaults on first start.

gateway:
  host: 127.0.0.1
  port: 15020
  timeout: 1.0
drives:
  - label: pump
    driver: intek_spe_b_modbus
    unit_id: 1
    poll_interval: 1.0
    # max_frequency_hz: 50.0
failure_threshold: 3
stream_maxlen: 10000

• gateway — Modbus/TCP endpoint of the Scietex Modbus gateway.
• drives[].label — unique label; the registry key and the stream key segment.
• drives[].driver — HAL driver entry point name (see the table above).
• drives[].unit_id — Modbus unit id the gateway routes to the drive. This is the drive's own configured address (Pd.02 on SPE-B, 09-00 on E5-8200, H5-01 on E4-8400).
• drives[].poll_interval — seconds between reads.
• drives[].max_frequency_hz — optional. Only meaningful for a drive whose protocol does not expose its configured maximum output frequency; the driver uses it to derive frequency_percent and to bound set_frequency. Omit it to keep the driver's own default (SPE-B reads P0.10 from the drive, E4-8400 reads E1-04; E5-8200 falls back to 50 Hz).
• failure_threshold — consecutive failed reads before a drive is reported as disconnected. One dropped frame on an RS485 segment must not flip the status.
• stream_maxlen — entries retained per drive's readings stream.

A configuration change at runtime is restart-required: the drive registry is not live-rebuilt.

Tasks

Control lane:

• monitoring:start / monitoring:stop — payload {"label": "pump"} or empty for every drive.

Data lane:

• vfd:read — payload {"label": "pump"}. Returns every parameter field plus the decoded fault (error_code, error_message).
• vfd:start — {"label": "pump", "forward": true, "slow": false}.
• vfd:stop — {"label": "pump", "freewheel": false}.
• vfd:set-frequency — {"label": "pump", "frequency_hz": 42.5}.
• vfd:clear-error — {"label": "pump", "comm": false}.

Every control task is gated on the drive's declared capabilities, so an unsupported command is rejected as UNSUPPORTED before the driver is called. vfd:read is ungated.

Valkey keys

• Readings stream: scietex:{service}:{instance_id}:vfd:{label}:readings with fields ts, frequency_hz, frequency_percent, output_current, output_voltage, output_power, dc_bus_voltage, heatsink_temperature_c, motor_temperature_c, state. A field the drive does not report is written as an empty value, which is distinguishable from a reported 0.0.
• Telemetry: scietex:{service}:{instance_id}:telemetry, pushed every 2 s with a 6 s TTL.

Running

start-vfd-service --conf-dir /etc/scietex

Flags: --conf-dir (auto-resolved when omitted), --service-name (default $SCIETEX_SERVICE_NAME or VFD), --logging-level (default $SCIETEX_LOGGING_LEVEL or INFO). It runs in the foreground until SIGINT or SIGTERM.

Development

uv venv --python 3.14 .venv
uv pip install -e ".[dev,test,lint]" --python .venv/bin/python
tox -e format,lint,type,test

Container

./build_image.sh [--latest]

Builds and pushes registry.buro-nts.ru/scietex-vfd-service:<version> for linux/amd64 and linux/arm64. The image installs the released wheel from PyPI, so publish the version first.

Deployment prerequisites

The gateway speaks 8-N-1 on its serial port. Each drive must be configured to match before the gateway can talk to it:

• Intek SPE-B — Pd.01 → 3 (8-N-1), Pd.05 → 1 (standard Modbus), Pd.02 → the unit id used in vfd.yml.
• Vesper E5-8200 — 09-01 → 0 (RTU), 09-03 → 0 (1 stop bit), 09-04 → 0 (no parity), 09-05 → 0 (8 data bits), 09-00 → the unit id.
• Vesper E4-8400 — H5-08 → 0 (RTU), H5-09 → 0 (1 stop bit), H5-10 → 0 (8 data bits), H5-03 → 0 (no parity), H5-01 → the unit id.

The drive must also accept its setpoint from the communication channel (P0.03 = 9 on SPE-B, b1-01/b1-02 = 2 on E4-8400). See the HAL protocol docs for the full register maps.