What comes off the box

The wire, then the JSON

Camfil has not published a public API. GoldLink+ is a 4–20 mA / discrete gateway with a cellular modem. Jonesboro gets the frames. This is the contract the plant app would consume if that stream is opened.

1. Analog. ΔP, hopper, air, emissions, temperature sit on 4–20 mA loops. 4 mA is live-zero (broken wire ≠ empty). 20 mA is span.

2. Discrete. Fan run, pulse fire, hopper high, airlock moving, emission alarm are dry contacts. 0 / 24 V, not analog.

3. Inverter. Fan kW and rpm, when the VFD is on Modbus or a 4–20 mA speed out — GoldLink Connect already reads this in EMEA. US GoldLink+ is ΔP-first; the app still wants the kW if the panel has it.

4. Transport. Gateway digitizes, stamps, encrypts, ships over LTE/3G. Isolated from plant Ethernet. Typical period: 60 s telemetry, immediate on alarm, 5 min heartbeat.

5. Format we ask for. HTTPS POST of a JSON frame (below). CSV is the customer export, not the wire. MQTT is a fine alternate if Jonesboro already speaks it — same body, different pipe.

4–20 mA map

Signal	4 mA	20 mA	12 mA →
Filter ΔP (stage 1)	0 in. w.c.	10 in. w.c.	5.0 in. w.c.
Hopper / drum level	0 %	100 %	50.0 %
Compressed air header	0 psi	150 psi	75.0 psi
Outlet dust	0 mg/m³	50 mg/m³	25.0 mg/m³
Ambient temperature	-20 °F	180 °F	80.0 °F
Fan energy	0 kW	75 kW	37.5 kW

Last frame · GL-7A2C-4419

{
  "deviceId": "GL-7A2C-4419",
  "housingId": "xflo",
  "ts": "2026-08-20T02:00:00.000Z",
  "intervalSec": 60,
  "signals": {
    "dpInH2O": 3.73,
    "ambientF": 72.3,
    "pulsePerHour": 0,
    "airPsi": 91,
    "airScfm": 0,
    "hopperPct": 43,
    "emissionsMgM3": 0.05,
    "fanKw": 0.4,
    "fanRpm": 0,
    "airstreamF": 85.1,
    "airstreamRh": 41
  },
  "discretes": {
    "fanRun": false,
    "pulseFire": false,
    "hopperHigh": false,
    "airlockMoving": false,
    "emissionAlarm": false
  },
  "alarms": [],
  "meta": {
    "rssi": -69,
    "fw": "2.14.3",
    "seq": 8735
  }
}

Live tails

Press / grindseq 8735 · quiet3.73 in
Weld boothseq 8735 · quiet1.74 in
Tube laserseq 8735 · hopper_high2.91 in