Sungrow SG25-50CX-P2

Compatibility

Compatible with EpiSensor Edge over Modbus RTU or Modbus TCP

The SG25-50CX-P2 user manual Ver114 documents RS485 terminals A1 and B1 on COM2 for monitoring devices. Sungrow's Communication Protocol of Residential & Commercial PV Grid-Connected Inverters V1.1.80 lists every model in this family with its device type code and defines read-only FC04 running registers. Edge reads them as a Modbus RTU client through a ZMB-31 Modbus Interface or the Gateway serial port, or as a Modbus TCP client through the WiNet-S Ethernet port.

SG25CX-P2, SG30CX-P2, SG33CX-P2, SG36CX-P2, SG40CX-P2 and SG50CX-P2 (global versions), from user manual SG25_30_33_36_40_50CX-P2-UEN-Ver114-202604 and protocol V1.1.80 of 27 March 2026. The CN, P2H, LV and JP variants have other device type codes. Site check: read the device type code and nominal power, then compare active power with the inverter's own reading.

Connect it with

• Modbus Interface ZMB-3X From €399 ex VAT Configure
• Gateway ZGW-20 From €899 ex VAT Configure
• Evaluation Gateway on a Raspberry Pi Edge with one device licensed Free Set up

Models

Specifications

The SG-CX-P2 family covers 25 to 50 kW three-phase string inverters with two PV strings per MPPT, three MPPTs on the 25, 30 and 33 kW models and four on the 36, 40 and 50 kW models. COM2 carries the RS485 monitoring port, the meter port and the DI, DRM and DO contacts; COM1 takes a Sungrow communication module.²

Rated AC output power

25, 30, 33, 36, 40 and 50 kW²

Maximum AC output power

27.5, 33, 36.3, 40, 44 and 55 kVA (SG30CX-P2: 30 kVA in Germany, Belgium, Austria, Ukraine and Denmark)²

Independent MPP inputs

3 (SG25/30/33CX-P2); 4 (SG36/40/50CX-P2); 2 strings per MPPT^1, 2

Max. PV input voltage

1100 V²

Communication

RS485; WLAN and Ethernet through an optional module²

RS485 defaults

Slave address 1 (1 to 247), 9600 bit/s, 8 data bits, 1 stop bit, RTU; parity none or settable¹

Modbus TCP

Through WiNet-S, WiNet-S2 or Logger1000 Ethernet, port 502, DHCP by default¹

Degree of protection

IP66, corrosion class C5²

Operating ambient temperature

-30 to 60 °C; altitude up to 4000 m²

Interface

Documented measurements and integration boundaries for SG25-50CX-P2.

• FC04 input registers. Sungrow numbers registers from 5000 and the address sent is one less: register 5000 is wire address 4999 (0x1387).
• Identity: 4990 to 4999 serial number (UTF-8), 5000 device type code (U16), 5001 nominal active power (U16, 0.1 kW), 5002 output type (0 two phase, 1 3P4L, 2 3P3L).
• Energy: 5003 daily yield (U16, 0.1 kWh), 5004 to 5005 total yield (U32, kWh), 5144 to 5145 total yield (U32, 0.1 kWh).
• AC: 5019 to 5021 phase or line voltage (U16, 0.1 V, chosen by output type), 5022 to 5024 phase currents (U16, 0.1 A), 5031 to 5032 total active power (S32, W), 5033 to 5034 reactive power (S32, var), 5035 power factor (S16, 0.001), 5036 grid frequency (U16, 0.1 Hz), 5148 grid frequency (U16, 0.01 Hz).
• DC: 5011 to 5016 MPPT 1 to 3 voltage and current (0.1 V, 0.1 A), 5115 to 5116 MPPT 4, 5017 to 5018 total DC power (U32, W), 7013 onward string currents (U16, 0.01 A) where the hardware supports them.
• State: 5038 work state 1 (0x0 run, 0x8000 stop, 0x1400 standby, 0x5500 fault, 0x9100 alarm run), 5008 internal temperature (S16, 0.1 °C), 5071 array insulation resistance (U16, 1 kΩ).
• 32-bit values send the low-order register first: U32 0x01020304 arrives as 03 04 01 02. Unavailable reads return 0xFFFF (U16), 0xFFFFFFFF (U32), 0x7FFF (S16) or 0x7FFFFFFF (S32).

Setup

1. Choose one monitoring link

   Use either COM2 RS485 (A1 and B1) or a WiNet-S module on COM1. The user manual says that once a communication module is in use, a data logger must not be connected on RS485 at the same time. Keep A2 and B2 for the Smart Energy Meter.

2. Match the serial settings

   This guide uses protocol V1.1.80 and user manual Ver114. The protocol gives slave address 1 by default (settable from 1 to 247), 9600 bit/s, 8 data bits, 1 stop bit and RTU mode; parity is none or settable. Keep one Modbus master on the line.

3. Read the device type code first

   Send FC04 to wire address 4999 (register 5000), quantity 2. The first word is the device type code (0x2C32 for SG50CX-P2, 0x2C35 for SG33CX-P2) and the second is nominal active power in 0.1 kW. Record both with the nameplate before reading measurements.

4. Decode 32-bit values low word first

   Total active power is S32 at registers 5031 to 5032: send FC04 to 5030, quantity 2. Sungrow sends the low-order word first, so combine as high × 65536 + low and subtract 4294967296 if bit 31 is set. A reply of 0x7FFFFFFF is unavailable, not real power.

5. Compare and keep control out of scope

   Compare active power and grid frequency with the iSolarCloud or local app reading while the inverter is running (work state 0x0). The RW registers in section 2.2 (start and stop, power limits) use FC03, FC06 and FC10 and are outside this guide; control needs the site owner's and Sungrow's agreement.

Common questions

Which function code does the SG50CX-P2 use for running data?

FC04, read input registers. Table 3 of the protocol marks the running information as read-only with Modbus command 0x04. The parameter registers in table 4 use FC03, FC06 and FC10.¹

Why is register 5031 sent as address 5030?

The protocol says to visit every register by subtracting 1 from its address: register 5000 to 5001 is read at address 4999 to 5000. The same rule moves 5031 to 5030.¹

Can I use COM2 RS485 and a WiNet-S module at the same time?

The user manual says that once a communication module is in use, the inverter must not be connected to a data logger over RS485 at the same time. Choose one monitoring link for Edge.²

How do I tell an SG36CX-P2 from an SG40CX-P2 over Modbus?

Read register 5000. The SG36CX-P2 returns 0x2C36 and the SG40CX-P2 returns 0x2C37. Both have four MPPTs, so the device type, not the MPPT count, identifies the model.¹