SunSpec Model 16 — Simple IP Network
SunSpec Model 16 is a standardized information model defined by the SunSpec Alliance for reading and writing the IP network configuration of any SunSpec-compliant DER device over Modbus TCP. This template gives your ModbusCloud portal access to the device's interface name, IP configuration mode, assigned IPv4 address, subnet mask, default gateway, primary and secondary DNS servers, and link control. Because Model 16 is vendor-neutral, the same template works across inverters, energy meters, and battery storage controllers that implement the SunSpec standard. Verifying and correcting network settings remotely removes the need for on-site access.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 11, read and write
- Brand
- SunSpec
- Last updated
Registers (11)
11 read, 8 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| id | Read | ||||
| l | Read | ||||
| nam | Read and write | ||||
| cfg | Read | ||||
| ctl | Read and write | ||||
| addr | Read and write | ||||
| msk | Read and write | ||||
| gw | Read and write | ||||
| dns1 | Read and write | ||||
| dns2 | Read and write | ||||
| lnkctl | Read and write |
Loading registers…
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Verify the assigned IPv4 address of a remote SunSpec device without visiting the site.
- Confirm the subnet mask and gateway are correct after a network infrastructure change.
- Monitor the interface enable state to detect unexpected link dropouts across multiple sites.
- Audit DNS server settings on SunSpec devices during a company-wide network migration.
- Compare IP configuration mode across a fleet to identify devices still using DHCP when static addressing is required.
Installation
Confirm the target device supports SunSpec Model 16 by checking its Modbus register map or SunSpec PICS document; most SunSpec-compliant inverters and meters with Ethernet interfaces include this model.
Connect the device to the same LAN segment as the ModbusCloud Gateway and ensure TCP port 502 is reachable from the Gateway to the device.
In the ModbusCloud portal, add a new device, import the SunSpec Model 16 Simple IP Network template, and set the correct unit ID and base address offset for the target device.
Read back the addr register and compare it to the device's known IP address to confirm the template is polling the correct model block.
Things to watch for
All string registers return empty or garbled values. Why?
SunSpec strings are UTF-8 encoded and null-padded to their full declared length. Some Modbus clients that do not strip trailing null bytes display garbage. Verify your gateway firmware handles null-terminated SunSpec strings correctly, and read the full register width declared in the model block length register l.
The gateway connects but no register values appear at all.
SunSpec Model 16 is positioned at a dynamic offset within the device Modbus map, not at a fixed absolute address. The model block starts where the device places it after the SunS marker and Common Model. Scan from the SunS marker at address 0, 40000, or 50000 to locate the correct base address before applying this template.
Writing to addr, msk, or gw caused the device to go offline.
Writing network configuration registers such as addr, msk, gw, dns1, dns2, or lnkctl takes effect immediately on many devices and will disconnect the device from the network if incorrect values are written. Always prepare and verify new settings before writing. Have physical access arranged as a fallback before making any write operations.
The cfg register reads an unexpected numeric code. What does it mean?
The cfg register is an enumeration where each numeric value represents an IP assignment mode, typically 0 for unknown, 1 for DHCP, and 2 for static. The exact symbol mapping is defined in the SunSpec Model 16 SMDX specification. Cross-check the raw value against that table to determine the current mode.
Knowledge base articles for this device
SunSpec Modbus: one register map for many inverters
SunSpec Modbus is the open register map SMA, Fronius, SolarEdge and Kostal share. The layout, int+SF vs float, the TCP port per brand and reading a mixed fleet.
Fronius Modbus: read a Symo GEN24 over Modbus TCP
Fronius Modbus explained: enable Modbus TCP on the Symo GEN24 on port 502, choose between int+SF and float, read the right SunSpec registers and scale them correctly. Practical guide for solar installers.
SMA Modbus: reading a Sunny Boy over Modbus TCP (installers)
SMA Modbus explained: enable the Modbus TCP server on port 502, choose between the SMA profile (unit ID 3) and SunSpec (unit ID 126), read the right registers, and handle the NaN values at night. Practical guide for installers.
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