SunSpec Model 145 — Extended Settings
SunSpec Model 145 is the Extended Settings model in the SunSpec inverter control suite, used on solar inverters and DER devices that implement the SunSpec Modbus TCP standard. The template reads the model identifier and block length, and provides read/write access to six ramp rate setpoints: normal ramp-up and ramp-down rates, emergency ramp-up and ramp-down rates, and soft-start connect ramp-up and ramp-down rates, all expressed as a percentage of maximum current per second. It also exposes the default active current ramp rate and a shared scale factor. Importing this template lets installers audit and adjust inverter ramp behavior directly from the ModbusCloud portal.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 10, read and write
- Brand
- SunSpec
- Last updated
Registers (10)
10 read, 7 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| id | Read | ||||
| l | Read | ||||
| nomrmpuprte | Pct | Read and write | |||
| nomrmpdnrte | Pct | Read and write | |||
| emgrmpuprte | Pct | Read and write | |||
| emgrmpdnrte | Pct | Read and write | |||
| connrmpuprte | Pct | Read and write | |||
| connrmpdnrte | Pct | Read and write | |||
| agra | Pct | Read and write | |||
| rmp_sf | Read |
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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 that normal ramp-up and ramp-down rates match grid operator requirements after commissioning a new inverter.
- Monitor the active current ramp rate register to confirm the correct scale factor is applied before writing any setpoints.
- Alert on unexpected changes to emergency ramp-down rates that could indicate unauthorized remote configuration of the inverter.
- Compare soft-start connect ramp rates across multiple sites to enforce a consistent reconnection profile after grid outages.
- Track ramp rate setpoint writes over time to build a change log for compliance reporting under grid code obligations.
Installation
Enable Modbus TCP on the inverter under the communication or Modbus section of its web interface, and note the assigned IP address and TCP port (default 502).
Connect the inverter to the same LAN segment as the ModbusCloud Gateway, or confirm an existing Ethernet path is reachable from the Gateway.
In your ModbusCloud portal, add the Gateway, import the SunSpec Model 145 template, and set the Modbus unit ID to match the inverter's configured unit ID (commonly 1 or 126 depending on manufacturer).
Spot-check register id (address 0) and confirm the returned value is 145, then read rmp_sf (address 9) to verify the scale factor before interpreting any ramp rate values.
Things to watch for
Why does the id register return a value other than 145?
The SunSpec model map is position-scanned: if your gateway is pointed at the wrong base address, it will read a different model's id register. Confirm the inverter's SunSpec map starts at address 0, 40000, or 50000, then re-import the template with the correct Modbus offset so that the id register lands at the right block-relative position.
Ramp rate values look far too large or too small. What is wrong?
All ramp rate registers (nomrmpuprte through agra) are raw integers that must be multiplied by 10 raised to the power of rmp_sf. Read rmp_sf first. A value of -2 means the raw register values are hundredths of a percent per second. Apply the scale factor before comparing values to your grid code limits.
The gateway connects but none of the ramp rate registers return data.
Some inverters only expose Model 145 if the firmware supports the SunSpec extended control suite. Confirm your device firmware meets the minimum version required by the manufacturer for Model 145, and that SunSpec extended controls are enabled in the device's communication settings.
Is it safe to write new ramp rate setpoints, and what should I watch out for?
Writing to nomrmpuprte, nomrmpdnrte, emgrmpuprte, emgrmpdnrte, connrmpuprte, or connrmpdnrte can immediately change how quickly the inverter ramps output current. Setting rates too high may violate grid operator limits or inverter protection thresholds. Always verify the rmp_sf scale factor and write one setpoint at a time, checking the inverter's status output before proceeding to the next.
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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