Sunwoda SunESS

Supported Devices

Device Type	Modbus TCP (Ethernet)	RS485	Curtailment
SunESS-5H	❌	✅	❌
SunESS-10H
SunESS-15H
SunESS-20H

Wiring

Ethernet

For correct ethernet wiring: Follow the the guidelines for ethernet wiring.

RS485

RS485 Wiring

• For correct RS485 wiring: Follow the guidelines for RS485 wiring.
• If the wiring shown in the table below is incorrect, please let us know.
• There is no general consensus in the industry about the usage of A and B for the RS485 polarity, so it may be counterintuitive and opposite of what you might expect for some devices.

Device	SmartgridOne Controller model OM1	SmartgridOne Controller model IG8	RS485-USB converter	RS485-Ethernet converter
	RS485 A	RS485_POS	RS485 A	TX+
	RS485 B	RS485_NEG	RS485 B	TX-
	RS GND	GND	Not available	G

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1. Overview

Sunwoda SunESS-H systems support external EMS integration using the PCS communication port, which provides RS485 (Modbus RTU) and CAN.
This document describes how to connect a SunESS system to an EMS using RS485 RTU.

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2. Required Hardware

2.1 PCS Communication Port

Located on the right side of the SunESS Control Module and labeled:

PCS Communication (RS485/CAN)

2.2 RS485 Pinout (RJ45)

Pin	Function	Wire Color
1	RS485 A	Orange-white
2	RS485 B	Orange
3	NC	Green-white
4	CANH	Blue
5	CANL	Blue-white
6	NC	Green
7	Wakeup +5V	Brown-white
8	Wakeup –	Brown

Only Pin 1 (A) and Pin 2 (B) are used for RS485.

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3. Wiring the SunESS to an EMS (RS485)

3.1 RS485 Wiring

• SunESS PCS Port EMS RTU Port
• Pin 1 (A) ---------> RS485 A (D+)
• Pin 2 (B) ---------> RS485 B (D-)

3.2 Cable Recommendations

• Twisted pair, shielded
• 24–18 AWG
• Ground shield at one side only (typically EMS side)

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4. Termination & RS485 Bus Rules

4.1 Termination

SunESS requires:

• 120 Ω resistor installed on COM1 port

When used in parallel systems, termination is applied only on the master unit.

4.2 RS485 Bus Rules

• Daisy-chain only (no star topology)
• A ↔ A and B ↔ B must be consistent across devices
• Ensure EMS termination is set appropriately (ON or off depending on your wiring)

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5. Configuring SunESS for EMS (RS485) Communication

Configuration is performed using the PowerLite app.

Steps

1. Connect to SunESS using Bluetooth/Wi-Fi
2. Enter the device settings
3. Open PCS Setting
4. Select the protocol: Default (INV-08)
   • Enables SunESS standard RS485/CAN protocol

This is required for EMS communication.

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6. EMS Communication Settings (Modbus RTU)

Note: Actual SunESS register maps are not included in the manufacturer manual and must be requested from Sunwoda or inverter/EMS vendor.

Typical working defaults:

Parameter	Value
Protocol	Modbus RTU
Baudrate	9600 or 19200
Data bits	8
Parity	None
Stop bits	1
Slave ID	1

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7. Parallel SunESS Systems

Up to 3 cabinets can be connected in parallel.

7.1 Battery-to-Battery Communication

• COM0 → COM1 is used for internal SunESS communication
• Daisy-chain between cabinets

7.2 EMS Connection

• Only the master SunESS communicates with the EMS
• Connect the EMS RS485 lines to the master’s PCS port

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8. Startup & Verification

8.1 Power-Up Sequence

1. Close inverter battery switch (if installed)
2. Close SunESS circuit breaker (MCB)
3. Hold Power button for ≥3 seconds
4. Display lights up and system boots

8.2 Communication Verification

EMS should:

• Poll the SunESS slave ID and receive valid Modbus responses
• Report SOC, voltage, current, alarms, etc.

SunESS should:

• Display solid status LED (normal operation)

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9. Troubleshooting

Common issues and checks:

Issue: EMS cannot read SunESS registers

• A/B reversed → swap RS485 A/B
• Termination missing → ensure 120 Ω installed at COM1
• Wrong PCS protocol → select Default (INV-08)
• Wrong Modbus settings → verify baud, parity, ID

Issue: Parallel system not synchronizing

• COM0/COM1 cables not daisy-chained correctly
• Slave cabinet not powered on
• Incorrect master selection

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10. Field Procedure (Quick Guide)

1. Wire RS485:
   • Pin 1 → EMS A
   • Pin 2 → EMS B
2. Install 120 Ω resistor on COM1
3. Configure PCS protocol = Default (INV-08)
4. Configure EMS Modbus settings
5. Power on SunESS
6. Verify Modbus communication