Sungrow SG125CX-P2

Commercial PV inverter

The SG125CX-P2 has its own device type in Sungrow's PV inverter protocol. A read-only Modbus RTU client can identify that type and read inverter power, state and energy, provided the site's existing logger and serial-bus ownership are respected. The manufacturer's RS485_1 RJ45 is serial wiring, not an Ethernet socket.

Sungrow SG125CX-P2 PV string inverter
  • Modbus RTU

Commercial PV inverter

Compatibility

Compatible through a qualified Modbus RTU monitoring path

Sungrow's SG125/110/75CX-P2 manual identifies RS485_1 for a monitoring device, and its PV inverter protocol V1.1.80 explicitly lists SG125CX-P2 as device type 0x2C2D with read-only registers and RTU framing.

SG125CX-P2 only, manual Ver19 (October 2025) and protocol V1.1.80 (March 2026). Confirm the installed regional variant, software, logger, serial address and exclusive-master arrangement before commissioning. No installed firmware minimum or tested site result is established here.

Connect it with

The system owner has approved an exclusive RTU master path and the occupied logger or communication module is accounted for

  • Modbus
  • Edge
  • Platforms
Commercial PV inverter
Interface
Gateway
Edge
Output
SG125CX-P2SG125CX-P2 RS485_1
Isolated serial interfaceApproved RS-485-to-host adapter
ZGW-20 GatewayHosts Edge locally
EpiSensor EdgeModbus client + register map
Customer platformMQTT · API · files
Modbus RTU · RS-485
Isolated serial
Runs locally
Optional onward data
Use RS485_1 for the monitoring bus, not the meter's RS485_2/3 terminals. Its terminal block and RJ45 are alternate wiring forms of the same interface. Do not attach a second RTU master to an occupied bus or parallel a third-party logger with the manufacturer's communication module. The customer-platform output is optional; Edge remains the local system of record.

Models

Download
ModelsInterfaceRoute into Edge
SG125CX-P212 MPPTs; protocol device type 0x2C2D; RS485_1 terminal block or serial RJ45Read-only FC04 through an approved exclusive-master RS-485 connection.
SG110CX-P2, original SG110CX and SG125CX-P3Different device types and model generationsCheck the exact installed model and its type code. Do not inherit this guide's electrical or software assumptions.

Specifications

The installation manual assigns RS485_1 to the COM100E or another monitoring device and reserves RS485_2/3 for the external meter. The RS485_1 terminal block and RJ45 carry the same serial function; the latter is not Ethernet. Sungrow also warns against connecting a third-party RS485 logger alongside its communication module.1

Exact model
SG125CX-P2, protocol device type 0x2C2D12
AC rating
125 kW rated output; confirm the regional AC voltage variant on the installed nameplate1
Monitoring bus
RS485_1 A1/B1; the RJ45 alternative uses pin 3 for B and pin 6 for A1
Meter terminals
RS485_2/3 are assigned to the external meter, not the third-party monitoring bus1
RTU defaults
9600 bit/s, 8 data bits, 1 stop bit, no parity by default; inverter address 1 by default, settable 1–2472
Identity read
FC04 at one-based register 5000, wire address 4999, returns 0x2C2D for this model2
Active-power read
FC04 at registers 5031–5032, wire start 5030; signed 32-bit watts, low word first2

Interface

Documented measurements and integration boundaries for SG125CX-P2.

  • Device type and serial identity establish that the measurement belongs to the expected inverter.
  • Documented running information includes active power, energy yield, work state and selected phase and MPPT measurements.
  • These are inverter telemetry points. A separate, appropriately specified point-of-connection meter is needed for independent export or settlement evidence.

Assessment

SG125CX-P2 with the documented RS485_1 path and protocol V1.1.80. This is an interface design and bounded read, not a record of tested site operation or approved control.

InteroperabilitySupported with conditions
The exact model and monitoring serial interface appear in manufacturer documentation; the installed logger and bus ownership constrain commissioning.12
AccuracySupported with conditions
Power units, signed representation and address convention are documented. Inverter values do not replace an independent connection-point meter.2
SecurityNot yet assessed
The cited RTU interface does not establish authenticated or encrypted device messages. Restrict physical and network access in the site design.12
ReliabilityNot yet assessed
No site availability, polling-loss recovery or historical backfill guarantee is established for this connection.1
RuggednessSupported with conditions
The exact manual specifies outdoor enclosure and operating limits; preserve regional variant and installation conditions.1
ScalabilitySupported with conditions
The manual documents a multi-inverter RS485 daisy chain, but address uniqueness and the one-master topology remain site constraints.12
LifecycleNot yet assessed
Versioned documents exist, but they do not guarantee firmware support or a replacement lifetime for an installed unit.12

Setup

Check identity before reading active power

These are synthetic request and data examples, not measurements from a commissioned inverter. Include the actual slave address and a CRC-checked response frame at the site.

Identity request
FC04, wire address 4999 (0x1387), quantity 1. The returned type 0x2C2D identifies SG125CX-P2.
Power request
FC04, wire address 5030 (0x13A6), quantity 2. This selects documented registers 5031–5032.
Synthetic power data
0xE848 followed by 0x0001 combines low word first to 0x0001E848, or 125000 W.
Unavailable value
The signed 32-bit sentinel 0x7FFFFFFF indicates unavailable data; do not chart it as output.
Acceptance boundary
Confirm type, function, byte count, unit, word order, CRC and a live reference before adding further points.

Acceptance: A checked read establishes one monitoring path. It does not authorise power commands, protection changes or market dispatch.

  1. Record the complete SG125CX-P2 nameplate, country variant, firmware, connected WiNet or COM logger and the existing monitoring or plant-control owner.

    Do not assume a free bus because two connector forms are present.

  2. Obtain approval for a single RTU master.

    Use RS485_1 A1/B1 or its serial RJ45 wiring, following the manufacturer's installation instructions. Keep RS485_2/3 meter wiring, local stop, alarms and protection untouched.

  3. Confirm address and serial framing on the installed system; the published 9600 bit/s, 8N1 and address 1 are defaults only.

    Validate complete responses and CRC16 before interpreting points.

  4. Read FC04 at wire address 4999 for one register and require device type 0x2C2D.

    If it differs, stop and identify the actual model rather than applying this map.

  5. Read active power using FC04, start address 5030 and quantity two.

    Decode low word first as signed 32-bit watts, reject the signed unavailable sentinel, and compare against a current local reference.

  6. Keep all power limiting, grid-code, start/stop and reactive-power writes outside this read-only commissioning scope.

    Inverter telemetry does not prove physical flexibility delivery or revenue-grade export.

Common questions

Is the RS485_1 RJ45 a network socket?
No. Sungrow's pinout assigns pin 3 to RS485 B and pin 6 to RS485 A. Optional Ethernet is a separate communications-module connection.1
Can another logger be attached beside the current logger?
Do not add a second RTU master to an occupied serial bus. The manual also warns against using a third-party RS485 logger at the same time as its communication module. Agree a documented export or engineered topology with the system owner.1
Does the register number 5031 go in the request?
No. The protocol says to subtract one from its one-based register numbers. The active-power pair starts at wire address 5030 and is read with FC04.2
Does a power reading prove dispatch delivery?
An inverter reading shows one device's reported state. Check the instruction, controller acknowledgement and an independent electrical measurement at the relevant boundary to evaluate delivered response.12

Sources

  1. SG125CX-P2 / SG110CX-P2 / SG75CX-P2 user manual, Ver19, October 2025 (opens in a new tab) (PDF) Sungrow
  2. Communication Protocol of Residential & Commercial PV Grid-Connected Inverters V1.1.80 (opens in a new tab) (PDF) Sungrow

Further reading

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