spdevice — Sparkplug B CNC machine simulator

A realistic Sparkplug B edge node simulator that models a CNC machining centre. Publishes NBIRTH / NDATA / NDEATH to any MQTT broker and responds to NCMD rebirth commands from host applications or spmon.

spdevice  ● Connected  localhost:1883  group:tedge  node:sim-cnc01  seq:14  pub:3
┌─ Machine State: RUNNING  [32s]  prog: O1001_ROUGH ───┐ ┌─ Event Log ───────────────┐
│                                                      │ │ 10:14:21 ● program_start  │
│ Spindle                                              │ │   Starting O1001_ROUGH    │
│   speed.rpm       7,843.0 rpm  ████████░░            │ │ 10:14:08 ● door_close     │
│   load.pct           63.2 %   ███████░░░             │ │ 10:14:06 ● door_open      │
│   temp.celsius       68.4 °C  ████░░░░░░             │ │ 10:14:04 ● program_end    │
│                                                      │ │   O3003_PROFILE — parts:4 │
│ Feed & Motion                                        │ │ 10:13:52 ◈ HighSpindleTemp│
│   feed.rate        782.0 mm/min                      │ │           RAISED          │
│   axis.x.pos       103.4 mm                          │ │ 10:12:19 ◇ HighSpindleTemp│
│   axis.y.pos        55.0 mm                          │ │           cleared         │
│   axis.z.pos        12.9 mm                          │ │ 10:11:44 ● tool_change    │
│                                                      │ │   Tool change → T07       │
│ Coolant                                              │ └──────────────────────────-┘
│   temp.celsius       26.1 °C
│   flow.lpm            8.2 L/min  ██████░░░░
│
│ Hydraulics
│   pressure.bar      142.7 bar  █████░░░░░
│
│ Power
│   power.kw            3.74 kW
│
│ Counters
│   cycle.count            4
│   part.count             4
│
│ I/O
│   door.open          false
│   estop.active       false
│
│ Alarms
│   HighSpindleTemp    false
│   LowCoolantFlow     false
│   HighHydraulicPressure false
│   EStop              false
└───────────────────────────────────────────────────────┘
  interval:5s  next: 2.1s  p pause    r rebirth    q quit

Build

just build

Usage

# Connect to local broker with defaults (group=tedge, node=sim-cnc01, interval=5s)
./spdevice

# Custom broker and faster publishing
./spdevice --broker 192.168.1.10:1883 --interval 1s

# Different group / node ID (must match your flow.toml or host application config)
./spdevice --group factory1 --node cnc-line-a --interval 2s

Flags

Flag	Default	Description
--broker	localhost:1883	MQTT broker host:port
--group	tedge	Sparkplug B Group ID
--node	sim-cnc01	Sparkplug B Edge Node ID
--interval	5s	Minimum publish interval — use 1s, 500ms, etc.

Keybindings

Key	Action
p	Pause / resume simulation and publishing
r	Send NBIRTH immediately (re-declare all metrics with aliases)
q	Publish NDEATH then quit

Simulated metrics

Metric	Type	Range	Alarm threshold
spindle.speed.rpm	Double	0 – 12 000 rpm
spindle.load.pct	Double	0 – 100 %	warn > 90 %
spindle.temperature.celsius	Double	20 – 90 °C	alarm > 83 °C
feed.rate.mm_per_min	Double	0 – 1 000
axis.{x,y,z}.position.mm	Double	0 – 500 mm
coolant.temperature.celsius	Double	20 – 35 °C	warn > 34 °C
coolant.flow.litres_per_min	Double	0 – 12 L/min	alarm < 2.0 L/min
hydraulic.pressure.bar	Double	130 – 165 bar	alarm > 157 bar
power.kw	Double	0 – 8 kW
program.cycle_count	Int64	incrementing
program.part_count	Int64	incrementing
door.open	Boolean
estop.active	Boolean
Alarm/*/Active	Boolean	true / false
Alarm/*/Text	String

Machine states

IDLE → WARMUP → RUNNING → COOLDOWN → IDLE
         ↕ any state → FAULT → IDLE

IDLE: Spindle stopped, axes parked, low power draw.
WARMUP: Spindle ramping up slowly, coolant flow increasing.
RUNNING: Full machining — spindle at target speed, axes executing path, all coolant and hydraulics active.
COOLDOWN: Spindle decelerating, door briefly opens for part removal, tool change on next cycle start.
FAULT: E-stop triggered (rare random event or thermal runaway), all motion stops.