Read Write registers

1200001Inverter RTC date and time(continuous read and write)RWU16N/AHigh Bit Year [19-99]
Low Bit Month [1-12]
2200011RWU16N/AHigh Bit Day [1-31]
Low Bit Hour [0-23]
3200021RWU16N/AHigh Bit Minute [0-59]
Low Bit Second [0-59]
4251001Grid Injection Power Limit SwitchU16N/A10:Off; 1:ON
5251031Grid Injection Power Limit SettingU16N/A1000[0.0%-100.0%]
6251041Smart Meter COM. StatusU16N/A10:Meter COM. Abnormal
1:Meter COM. Normal
7251052Phase A Power On MeterI32W1
8251072Phase B Power On MeterI32W1
9251092Phase C Power On MeterI32W1
10500001Hybrid Inverter Working Mode SettingU16N/A1Please refer to table Hybrid Inverter Working Modes
11500011EPS/UPS function SwitchU16N/A10:OFF;1:ON
12500041Off-grid Voltage SettingU16V10
13500051Off-grid Frequency SettingU16Hz100[45.00-65.00]Hz
14500061Off-grid asymmetric output function switchU16N/A10:OFF;1:ON
15500071Peak Load Shifting SwitchU16N/A10:OFF;1:ON
16500091Max. Grid Power Value SettingU16kVA10
17502021Inverter AC Power SettingU16N/A10:Off
1: Total Power Setting, Register: 50203
2: Power on each Phase Setting, Registers: 50204-50206
18502031Total AC Power SettingI16kW100Total Power Scheduling Settings
19502041Phase A Power SettingI16kW100Phase A Power Scheduling Settings
20502051Phase B Power SettingI16kW100Phase B Power Scheduling Settings
21502061Power C Power SettingI16kW100Phase C Power Scheduling Settings
22502071Battery Power SettingI16kW100
23502081Max. AC Power Limit SettingI16kW100
24502091Min. AC Power Limit SettingI16kW100
25502101Priority Power Output SettingU16NA10:PV Output Priority 1:Battery Output Priority
26502111PV Power SettingU16kW100
27525001Battery ConfigurationU16N/A1Please Refer to table Battery configuration
29525021On-grid Battery SOC Protection SwitchU16N/A10:OFF,1:ON
30525031On-grid Battery End SOCU16N/A1000[0.0%-100.0%]
31525041Off-grid Battery SOC Protection SwitchU16N/A10:OFF,1:ON
32525051Off-grid Battery End SOCU16N/A1000[0.0%-100.0%]
34530061Scheduled Charge&DischargeU16N/A1bit0- bit5 stands for period1-period6,
bit7-bit15 Reserved;
0: disable
1: enable
35530071Charge/Discharge SettingU16N/A1Period1:
36530081Battery Charge ByU16N/A1Period1:
Reserved: 0xFF
38530101Power LimitU16N/A1000Period1:
Reserved: 0xFF
40530121Start TimeU16N/A1Period1:
High 8bits(Hour):[0,23]
Low 8bits(Mins):[0,59]
41530131Stop TimeU16N/A1
Same Period1
43530151Battery Charge ByU16N/A1
45530171Power LimitU16N/A1000
47530191Start TimeU16N/A1
48530201Stop TimeU16N/A1
Same as Period1
50530221Battery Charge ByU16N/A1
52530241Power LimitU16N/A1000
54530261Start TimeU16N/A1
55530271Stop TimeU16N/A1
Same as Period1
57530291Battery Charge ByU16N/A1
59530311Power LimitU16N/A1000
61530331Start TimeU16N/A1
62530341Stop TimeU16N/A1
Same as Period1
64530361Battery Charge ByU16N/A1
66530381Power LimitU16N/A1000
68530401Start TimeU16N/A1
69530411Stop TimeU16N/A1
Same as Period1
71530431Battery Charge ByU16N/A1
73530451Power LimitU16N/A1000
75530471Start TimeU16N/A1
76530481Stop TimeU16N/A1
77535008BMSVersionSTRN/A1Only for EMS
78535081BMS StatusU16N/A1Please refer to table BMS control
79535092BMS ErrorCodeU32N/A1Please refer to table BMS fault registers
80535112BMS ProtectionCodeU32N/A1
81535132BMS WarnCodeU32N/A1
82535151BMSChargeVoltLimitU16V10Only for EMS
84535171BMSDishargeVoltLimitU16V10Only for EMS

Write registers continue on the next page…


  • Hey
    Thanks, great information, very helpful.
    I’m owning an M-Tec system (the same, just different badge) and I’m currently trying to decipher some of the values and there are two that confuse me, maybe you got some more experience and you can help.
    What is Invt_A_P (And B and C of course)? In total it’s always up to 100 W above the sum of PV power and battery power. PV power and battery power are matching the values in the official dashboard, so I do trust them, at least as far as you can trust companies and their dashboards. Might it be the inverter power including heat losses? The inverter has a big heat sink and it is still above 40 °C, so that might match. I’ wouldn’t be surprised at all if the company hides the system losses in its dashboard. What’s your experience, do you think that might be right?
    Second items isn’t that important, just confusing: Backup power is always something like 60 W, though the backup line isn’t even connected. I guess that’s a measurement error, probably tolerances on the current sensors, plus maybe something like a tolerance compensation to be sure to never get a measurement below the real value. Do you see something similar?
    Hm, while writing this, I begin to wonder if the things might be related, with the system pulling it’s own power demand from the backup line.


    • Hi Holger,
      Invt_A_P (And B and C of course) translates to Inverter_L1_Power, Inverter_L2_Power and Inverter_L3_Power in Germany and is simply the english naming convention for the three phases in use. It represents the AC output power of the inverter per phase and is not directly related to either PV power nor battery power.
      You don’t find these values on the overview page of the app or webpage, but you can see it under Devices -> realtime information in the “inverter AC parameters” block


  • Hi, thank you, this site helped a lot. I also wanted to connect via Modbus TCP, this worked for me at the end (i just used QModMaster):
    Slave-IP: IP of the Inverter (device “espressif” on the router)
    TCP-Port: 502
    Modbud Mode: TCP
    Unit ID: 255
    Read Holding Registers (0x03)
    Start Address: e.g. 33001 for the charging state (you must add 1 to the register number)

    This should word on Wattsonic inverters Gen3, M-Tec Gen3 and some other brands with the same inverter inside.

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