The established protocol for easy integration of SMA inverters

Modbus protocol interface

Yield optimization directly from the inverter

With the Modbus protocol interface, SMA makes the flexible integration of inverters possible. The benefits are obvious. Through the use of this well-known, public industry standard, other providers can integrate SMA devices into their systems without having to follow the SMA-specific inverter protocol. System data is transferred via this standardized protocol for further processing and can, as such, be flexibly integrated into any system regardless of the manufacturer. The importance for system planning: You can use SMA inverters in your preferred standard system at any time without having to take manufacturer specifics into account. Direct inverter integration into control room systems or the connection of inverters in building automation systems are both ideal applications.

More benefits

More benefits

  • Easy connection of SMA inverters
  • Documented protocol standard for quick system integration


  • Manufacturer-independent interoperability of system components through uniform protocol language


  • Protocols uploaded directly to inverter
  • Retrieval of detailed values possible
  • High-performance Ethernet interface for the connection of data loggers or control room operated PV systems


  • Modbus recognized as an international and widespread industry standard
  • SMA, a SunSpec Alliance member, contributes to implementation of a protocol standard for PV systems

SMA Modbus: General Information

Why is the Modbus interface reaction time defined as only five to ten seconds in the technical documentation?

How do I read the number of MPP trackers?

Why does Modbus crash after a few days?

Why do I receive a NaN instead of a value for some registers at night?

Why is the register's current value not displayed and only is -1 or the maximum value showing up?

Why were only 9 requests (polls) out of 270 answered with OK, for example, and how can these connection problems be resolved?

Why are two answers occasionally sent via Modbus upon request?

What does error code 11 mean when requesting some Modbus registers?

SMA Modbus: Registers

30797 – grid current of line conductor

30799 – grid current of line conductor

30801 – grid current of line conductor

40016 – Maximum change limit value

40016 – Active power set point default setting

40155 – MAC address

40497 – MAC address

SMA SunSpec Modbus: General Information

Which registers may be cyclically written for system control without destroying the device’s flash memory?

SMA SunSpec Modbus: Registers

40186 – model ID (ID)

40217 – DC power (DCW), in W*10

40219 – internal temperature (TmpCab), in °C

40224 – operating status (St)

40353 – choking (WMaxLim_Ena)

40358 – fixed power factor (OutPFSet_Ena)

40366 – control of reactive power limitation percentage (VArPct_Ena)

40632 – ID of MPP tracker (ID): 1

40641 – DC input 1 (DCA), in A*10

40642 – DC voltage input 1 (DCV), in V*10

40643 – DC power input 1 (DCW), in W*10

40652 – ID of MPP tracker (ID): 2

40661 – DC input 2 (DCA), in A*10

40662 – DC voltage input 2 (DCV), in V*10

40663 – DC power input 2 (DCW), in W*10

Modbus protocol interface


Modbus protocol interface


With Sunny Design, you can plan your tailor-made PV system in just a few clicks.

Planning tool Sunny Design

With Sunny Design, you can plan your tailor-made PV system in just a few clicks.

Plan your system now

Do you have any questions?

If you have any questions, please contact SMA.

Contact us now