SmartGen HGM7220N

Single-generator AMF controller

HGM7220N is a single-generator automatic mains-failure controller with RS-485 monitoring. SmartGen publishes its Modbus protocol, including individual alarm flags and scaled electrical measurements. HGM7220S adds synchronised changeover; the N and S roles should stay distinct in the plant inventory.

HGM7220N controller
  • Modbus RTU

Single-generator AMF controller

Compatibility

Documented Modbus RTU interface

RS-485 Modbus RTU; do not infer an Ethernet socket from cloud-monitoring accessories

The S variant supports synchronised changeover. A remote cloud module does not turn the N controller’s own RS-485 port into native Modbus TCP.

Connect it with

When the documented monitoring interface is fitted and configured

  • Modbus
  • Edge
  • Platforms
Single-generator AMF controller
Interface
Gateway
Edge
Output
HGM7220NHGM7220N
Isolated serial interfaceApproved RS-485-to-host adapter
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeEdge Gateway
Customer platformMQTT · API · files
Modbus RTU · RS-485
Isolated serial
Runs locally
Optional onward data
Set the controller address and serial format to match the monitoring client. Use the HGM7220N/7220S protocol table for FC03 measurement reads, retain each unit and signedness, and compare voltage and frequency with the display before collecting longer trends. The customer-platform output is optional; Edge remains the local system of record.

Models

Download
ModelsInterfaceRoute into Edge
HGM7220NRS-485 Modbus RTU; do not infer an Ethernet socket from cloud-monitoring accessoriesSet the controller address and serial format to match the monitoring client. Use the HGM7220N/7220S protocol table for FC03 measurement reads, retain each unit and signedness, and compare voltage and frequency with the display before collecting longer trends.

Specifications

The S variant supports synchronised changeover. A remote cloud module does not turn the N controller’s own RS-485 port into native Modbus TCP.12

Plant role
Single-generator AMF controller1
Monitoring and configuration
RS-485 Modbus RTU; do not infer an Ethernet socket from cloud-monitoring accessories2
Model distinction
The S variant supports synchronised changeover. A remote cloud module does not turn the N controller’s own RS-485 port into native Modbus TCP.12
Panel protection
Front panel IP65.1

Interface

Documented measurements and integration boundaries for HGM7220N.

  • Generator and mains voltage, frequency and power values in the Modbus table
  • Engine analogue measurements and operating state
  • Separate alarm flags, breaker states and controller mode

Assessment

RS-485 Modbus RTU; do not infer an Ethernet socket from cloud-monitoring accessories

InteroperabilitySupported with conditions
RS-485 Modbus RTU; do not infer an Ethernet socket from cloud-monitoring accessories12
AccuracySupported with conditions
The documentation identifies electrical and operating measurements for this plant role. CT configuration and measurement location determine how those values are used.12
SecurityNot yet assessed
The cited documentation does not establish an authenticated, encrypted Edge monitoring connection.
ReliabilityNot yet assessed
The controller application distinguishes operating conditions and alarms. Retain communication availability alongside the plant readings.
RuggednessSupported with conditions
Front panel IP65.1
ScalabilityNot yet assessed
Assign one device identity per controller and keep generator, mains and busbar measurements separate.
LifecycleSupported with conditions
Retain the exact model documentation and configuration when replacing a controller or communication module.12

Setup

Read generator frequency

Best-effort first read from HGM7220N/7220S protocol V1.2, 19 May 2025, page 18. Compare this value with the generator display before adding more points.

Function
03, read holding registers; quantity 1
Address convention
Table 0084 / PLC reference 40085 means decimal PDU offset 84 (0x0054)
Request PDU
03 00 54 00 01
Decode
Unsigned 16-bit value, 0.01 Hz per count. Example 0x1388 = 5000 = 50.00 Hz.

Acceptance: Compare with generator frequency, rather than mains frequency at offset 64.

  1. Set the controller address and serial format to match the monitoring client.

    Use the HGM7220N/7220S protocol table for FC03 measurement reads, retain each unit and signedness, and compare voltage and frequency with the display before collecting longer trends.

  2. Record CT ratios and the physical measurement location.

    Compare the first electrical values with the controller display before using them in totals or trends.

  3. Keep missing responses distinct from a stopped generator.

    Store communication availability beside running state so a disconnected cable does not look like healthy standby.

  4. Build a read-only point list for monitoring.

    Remote start, synchronisation and breaker operation require a separate control design with the existing panel interlocks and feedback.

Sources

  1. HGM7220N product (opens in a new tab) (PDF) SmartGen
  2. HGM7220N protocol (opens in a new tab) (PDF) SmartGen

Further reading

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