Prometheus Exporter for Datakom D500

A Go-based exporter for monitoring Datakom D-500 and D-500LITE MK2 genset control units. The program reads data via the Modbus TCP protocol directly from the controller's register map.

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📊 Key Metrics

The exporter collects a full set of data regarding the state of the mains, generator, and engine:

• Mains: 3-phase voltage (L1-L3) and current (I1-I3).

• Generator: Active power (kW) , frequency (Hz) , and a total active energy counter (kWh).

• Engine: Battery voltage , coolant temperature , fuel level , and engine speed (RPM).

• Service: Total engine run hours and countdown of hours/days remaining until the next scheduled maintenance.

• Status: Current controller mode (Mode) and detailed operation state (Status).

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⚙️ Configuration (Environment Variables)

For deployment flexibility and support for multiple networks/sites, configuration is handled via environment variables:

Variable	Description	Default Value
DATAKOM_HOST	IP address or hostname of the controller	192.168.100.100
DATAKOM_PORT	Modbus TCP port (configured in Rainbow Plus)	502
EXPORTER_PORT	The port on which the exporter serves metrics	8000

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🛠 Technical Implementation Details

According to Datakom D-500 specifications:

1. 32-bit Values: These are stored in two consecutive registers. The high-order 16 bits (MSB) are in the first register, and the low-order 16 bits (LSB) are in the second.

2. Scaling: Values require the application of divisors (10 or 100) to obtain real units of measurement, such as Volts, Amperes, or Hours.

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🚀 Quick Start

1. Install Dependencies

go get github.com/prometheus/client_golang/prometheus
go get github.com/simonvetter/modbus

2. Run the Exporter

To monitor a specific network, run the binary with the appropriate parameters:

export DATAKOM_HOST=192.168.100.100
export DATAKOM_PORT=502
export EXPORTER_PORT=8000
go run main.go

3. Verify the Data

Open your browser or use curl: http://localhost:8000/metrics

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🏗 Multi-network Deployment

If you have three independent networks/generators, you can run three separate processes or containers on different exporter ports (e.g., 8000, 8001, 8002), specifying the unique controller IP addresses in DATAKOM_HOST.

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📊 Full Modbus Register Map (D-500)

The exporter uses the standard Datakom address map (32-bit values occupy two 16-bit registers, high byte first):

Parameter	Address (Dec)	Data Size	Coefficient	Description
Mains Voltage L1	10240	32-bit	/ 10	Mains phase voltage L1 (V)
Mains Voltage L2	10242	32-bit	/ 10	Mains phase voltage L2 (V)
Mains Voltage L3	10244	32-bit	/ 10	Mains phase voltage L3 (V)
Mains Current I1	10264	32-bit	/ 10	Mains phase current I1 (A)
Mains Current I2	10266	32-bit	/ 10	Mains phase current I2 (A)
Mains Current I3	10268	32-bit	/ 10	Mains phase current I3 (A)
Genset Power Total	10294	32-bit	/ 10	Total active power (kW)
Mains Frequency	10338	16-bit	/ 100	Mains frequency (Hz)
Genset Frequency	10339	16-bit	/ 100	Genset frequency (Hz)
Battery Voltage	10341	16-bit	/ 100	Battery voltage (Vdc)
Coolant Temp	10362	16-bit	/ 10	Engine temperature (°C)
Fuel Level	10363	16-bit	/ 10	Fuel level (%)
Operation Status	10604	16-bit	x 1	Current status (0-25)
Engine Run Hours	10622	32-bit	/ 100	Total engine hours (h)
Total Genset Energy	10628	32-bit	/ 10	Total active energy (kWh)
Service-1 Hours	10634	32-bit	/ 100	Hours remaining to Service-1
Service-1 Days	10636	32-bit	/ 100	Days remaining to Service-1

🧩 Operation Status Decoding (ID 10604)

For ease of analysis in Grafana, the d500_op_status metric returns numerical values corresponding to the following states:

• 0 — Genset at rest
• 5 — Cranking (Starter active)
• 8 — Running off load
• 13 — Master genset on load
• 22 — Cooling down