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Step 1: Parse Adapter-Decoded Registers

The input is a synthetic line emitted after gateway decoding. Expanso splits its fields, applies the example register map, and produces JSON.

Boundary​

The gateway owns protocol polling, framing, reconnect behavior, device authentication, and raw-register decoding. This mapping starts with delimited text; it is not a Modbus client.

Reference configuration​

Partial snippet
input:
  socket:
    network: tcp
    address: 0.0.0.0:502
    codec: lines

pipeline:
  processors:
    - mapping: |
        let fields = content().string().split(";").fold({}, item -> item.tally.merge({ item.value.split("=").index(0): item.value.split("=").index(1) }))
        let reg = $fields.REG.number()
        let val = $fields.VAL.number()

        root.voltage_kv = if $reg == 40001 { $val / 100.0 } else { deleted() }
        root.device_id = $fields.DEVICE
        root.register = $reg
        root.raw_value = $val
        root.status = $fields.STATUS.number()
        root."@timestamp" = $fields.TS.number()

For register 40001, a value of 14823 becomes voltage_kv: 148.23. The mapping also retains the device identifier, register, raw value, status, and timestamp.

Review before implementation​

  • Confirm addressing conventions with the gateway and device documentation.
  • Confirm each unit and scale factor with the site owner.
  • Define behavior for missing, malformed, duplicated, or out-of-order fields.
  • Decide whether the socket port and record framing are appropriate for the deployment boundary.

This checked-in fragment has not been exercised against a protocol adapter or assessed for malformed-input behavior.

Source artifact: examples/integrations/scada-energy-edge/step-1-parse-registers.yaml.

Next: Inspect record selection.