ASCII / SCPI

YAML key: ascii

The ASCII adapter serves simple text protocols such as SCPI. It listens on TCP (or UDP), parses newline-terminated commands, and maps them to attributes or custom handlers.

Configuration Example

YAML

communication:
  ascii:
    port: 5025
    terminator: "\n"
    response_delay: 0.01
    response_jitter: 0.0
    mappings:
      "MEAS:VOLT?": "#out(voltage)"
      "CONF:MODE {mode}":
        "#attr(measurement_mode)": "mode"
        response: "ACK"

JSON

Key fields

• host (default: 0.0.0.0) — bind address

• port: TCP port. If omitted, SPX auto-assigns a free port starting at 5025 and writes the effective value into the instance at communication.ascii.port.

• transport (default: tcp) — tcp|udp

• terminator: command delimiter (\n, \r\n, etc.).

• response_delay: base delay inserted before responding (seconds).

• response_jitter: random delta added to delay (seconds).

• mappings: legacy command dictionary (still supported; converted internally to bindings). Each key is a command pattern.

  • A string value returns the referenced attribute.

  • A mapping updates attributes or invokes handlers; optional response overrides the reply.

• bindings: explicit binding definitions (see the spx-examples SCPI multimeter model for a concrete pattern).

Tip: In spx-examples, the SCPI multimeter model omits port so it can run multiple instances without collisions. See multimeter__scpi.yaml.

Placeholders

Commands may include placeholders ({mode}) that the adapter passes into the mapping as variables. You can write them back to attributes or use them in responses.

YAML

"CONF:VOLT {value}":
  "#attr(voltage_setpoint)": "value"
  response: "VOLT {value}"

JSON

Scenarios

Use scenarios to simulate link issues:

YAML

scenarios:
  ascii_disconnect:
    duration: 2.0
    call:
      path: communication.ascii.detach
      stop_path: communication.ascii.attach
  ascii_response_delay_spike:
    duration: 5.0
    overrides:
      communication.ascii.response_delay: 10.0

JSON

Tips

• Normalize commands to uppercase to avoid case mismatches.

• Use response_delay and response_jitter to emulate slow hardware.

• Validate mappings with MiL tests against SPX Server (see spx-examples multimeter__scpi.yaml and scpi_multimeter_sut_example.py).