I created a modbus sunspec server flow for nodered which seems to work, didn’t test the power limiting yet, although the value (100%) seems to read correct.
[{"id":"0e653fa492d095a3","type":"group","z":"af5e2095a73fd6b0","name":"SunSpec TCP Modbus Server 1","style":{"label":true},"nodes":["84679027d0b86a8e","0d232675e2162ea7","6b059763da11294d","3057eb4d3fc0a4c7","8aeba526ff040a8c","69dc5d0199b5e293","d29dea8b916c6d89","d35e32def6767db0","f9d097a063c97250"],"x":54,"y":2196.5,"w":892,"h":244.5},{"id":"84679027d0b86a8e","type":"modbus-server","z":"af5e2095a73fd6b0","g":"0e653fa492d095a3","name":"TCP Modbus PV Server","logEnabled":true,"hostname":"127.0.0.1","serverPort":"5021","responseDelay":100,"delayUnit":"ms","coilsBufferSize":"1000","holdingBufferSize":"1000","inputBufferSize":"1000","discreteBufferSize":"1000","showErrors":true,"showStatusActivities":true,"x":810,"y":2260,"wires":[[],[],[],[],[]]},{"id":"0d232675e2162ea7","type":"modbus-flex-write","z":"af5e2095a73fd6b0","g":"0e653fa492d095a3","name":"","showStatusActivities":true,"showErrors":true,"showWarnings":true,"server":"347fea107e1f82f1","emptyMsgOnFail":false,"keepMsgProperties":false,"delayOnStart":false,"startDelayTime":"","x":790,"y":2340,"wires":[[],[]]},{"id":"6b059763da11294d","type":"modbus-read","z":"af5e2095a73fd6b0","g":"0e653fa492d095a3","name":"Read PV Percentage","topic":"","showStatusActivities":true,"logIOActivities":false,"showErrors":true,"showWarnings":true,"unitid":"","dataType":"HoldingRegister","adr":"155","quantity":"1","rate":"5","rateUnit":"s","delayOnStart":false,"enableDeformedMessages":false,"startDelayTime":"","server":"347fea107e1f82f1","useIOFile":false,"ioFile":"","useIOForPayload":false,"emptyMsgOnFail":false,"x":200,"y":2400,"wires":[["69dc5d0199b5e293"],[]]},{"id":"3057eb4d3fc0a4c7","type":"function","z":"af5e2095a73fd6b0","g":"0e653fa492d095a3","name":"PV Data to Modbus Server","func":"/*\n \n SunSpec PV Modbus Server Data\n\n Based on:\n https://raw.githubusercontent.com/remcom/sunspec-esphome/refs/heads/master/components/sunspec/sunspec.cpp\n https://www.forum-fronius.pl/wp-content/uploads/asgarosforum/2812/Inverter_register_map.pdf\n\n*/\n\n// Hier kun je eenvoudig waarden aanpassen of koppelen aan je sensoren\nlet inv = { ac_w: msg.ac.watt|| 0,\n ac_a: msg.ac.amps || 0,\n ac_v: msg.ac.volt || 0,\n ac_hz: msg.ac.hz || 0,\n ac_kwh: msg.ac.kwh || 0,\n dc_w: msg.dc.watt || 0,\n dc_v: msg.dc.volt || 0,\n dc_a: msg.dc.amps || 0,\n temp: msg.temp || 0 };\n\n\nlet regs68 = new Array(46).fill(0xFFFF);\n\n// --- BLOCK 2: INVERTER MODEL (S101 - 1 fase) ---\nregs68[0] = 1;\nregs68[1] = 0xFFFF;\nregs68[2] = 101; \nregs68[3] = 50; \n\n// AC Waarden\nregs68[4] = Math.round(inv.ac_a * 100); // 40072: TotalAC Amps\nregs68[5] = Math.round(inv.ac_a * 100); // 40073: Phase A AC Amps\nregs68[8] &= -2 ; // 40076: AC Amps SF\nregs68[12] = Math.round(inv.ac_v); // 40080: AC Volts\nregs68[15] = 0; // 40083: AC vOLTS SF\nregs68[16] = Math.round(inv.ac_w); // 40084: AC Watts\nregs68[17] = 0; // 40085: AC Watts SF\nregs68[18] = Math.round(inv.ac_hz * 100); // 40086 AC Freq\nregs68[19] &= -2; // 40087 AC Freq SF\n\n// Energy\nregs68[26] = Math.round(inv.ac_kwh * 1000) >> 16;\nregs68[27] = Math.round(inv.ac_kwh * 1000) & 0xFFFF;\nregs68[28] = 0; // 40096: Wh SF\n\n\n// DC Waarden (Nu specifiek uit de array)\nregs68[29] = Math.round(inv.dc_a * 100); // 40097: DC Amps (SF -1)\nregs68[30] &= -2; // 40098: DC Amps SF\nregs68[31] = Math.round(inv.dc_v); // 40099: DC Volts\nregs68[32] = 0; // 40100: DC Volts SF\nregs68[33] = Math.round(inv.dc_w); // 40101: DC Watts\nregs68[34] = 0; // 40102: DC Watts SF\n\nregs68[35] = Math.round(inv.temp * 10); // 40103: Temperature\nregs68[39] &= -1; // 40107 Temperature SF\n\nregs68[40] = inv.ac_w > 0 ? 4 : 1; // 40108 Generating power (4) or off (1)\n\nregs68[42] = 0; // 40110 Events\nregs68[43] = 0; // 40111 Events\nregs68[44] = 0; // 40112 Events\nregs68[45] = 0; // 40113 Events\n\nreturn {\n payload: { value: regs68, 'fc': 16, 'unitid': 1, 'address': 68 , 'quantity': 46 }\n};\n","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":480,"y":2340,"wires":[["0d232675e2162ea7"]]},{"id":"8aeba526ff040a8c","type":"inject","z":"af5e2095a73fd6b0","g":"0e653fa492d095a3","name":"PV Values","props":[{"p":"ac.watt","v":"pv1.ac.power","vt":"global"},{"p":"ac.volt","v":"pv1.ac.voltage","vt":"global"},{"p":"ac.amps","v":"pv1.ac.current","vt":"global"},{"p":"ac.hz","v":"pv1.ac.frequency","vt":"global"},{"p":"ac.kwh","v":"pv1.ac.energy","vt":"global"},{"p":"dc.volt","v":"pv1.dc.voltage","vt":"global"},{"p":"dc.amps","v":"pv1.dc.current","vt":"global"},{"p":"dc.watt","v":"pv1.dc.power","vt":"global"},{"p":"temperature","v":"pv1.temperature","vt":"global"}],"repeat":"2","crontab":"","once":true,"onceDelay":"5","topic":"","x":170,"y":2340,"wires":[["3057eb4d3fc0a4c7"]]},{"id":"69dc5d0199b5e293","type":"function","z":"af5e2095a73fd6b0","g":"0e653fa492d095a3","name":"Get PV Percentage","func":"msg.payload = msg.payload[0];\n\nnode.status({\n fill: msg.payload === 100 ? \"green\" : msg.payload === 0 ? \"red\" : \"yellow\",\n shape: \"dot\",\n text: `PV Percentage=${msg.payload}`\n});\n\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":450,"y":2400,"wires":[["d29dea8b916c6d89"]]},{"id":"d29dea8b916c6d89","type":"change","z":"af5e2095a73fd6b0","g":"0e653fa492d095a3","name":"","rules":[{"t":"set","p":"pv1.percentage","pt":"global","to":"payload","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":810,"y":2400,"wires":[[]]},{"id":"d35e32def6767db0","type":"function","z":"af5e2095a73fd6b0","g":"0e653fa492d095a3","name":"PV Static Blocks to Modbus Server","func":"/*\n \n SunSpec PV Modbus Server Data\n\n Based on:\n https://raw.githubusercontent.com/remcom/sunspec-esphome/refs/heads/master/components/sunspec/sunspec.cpp\n https://www.forum-fronius.pl/wp-content/uploads/asgarosforum/2812/Inverter_register_map.pdf\n\n*/\n\nlet inv = { manufacturer: msg.manufacturer, \n model: msg.model,\n version: msg.version,\n serial: msg.serial,\n max_w: msg.maxwatt};\n\nlet regs = new Array(200).fill(0xFFFF);\n\n// --- BLOCK 1: COMMON MODEL (S1) ---\nregs[0] = 0x5375; // \"Su\"\nregs[1] = 0x6E53; // \"nS\"\nregs[2] = 1; // Model ID 1\nregs[3] = 66; // Lengte\n\n// Save inverter info\nfor (let i = 4; i < 68; i++) {\n regs[i] = 0;\n}\n\n// Manufacturer\nfor (let i = 0; i < inv.manufacturer.length && i < 32; i++) {\n let regIdx = 4 + Math.floor(i/2);\n if (i % 2 === 0) regs[regIdx] = inv.manufacturer.charCodeAt(i) << 8;\n else regs[regIdx] |= inv.manufacturer.charCodeAt(i);\n}\n\n// Model\nfor (let i = 0; i < inv.model.length && i < 32; i++) {\n let regIdx = 20 + Math.floor(i/2);\n if (i % 2 === 0) regs[regIdx] = inv.model.charCodeAt(i) << 8;\n else regs[regIdx] |= inv.model.charCodeAt(i);\n}\n\n// Options\nfor (let i = 0; i < 8; i++) {\n let regIdx = 36 + i;\n regs[regIdx] = 0;\n}\n\n\n// Version\nfor (let i = 0; i < inv.version.length && i < 16; i++) {\n let regIdx = 44 + Math.floor(i/2);\n if (i % 2 === 0) regs[regIdx] = inv.version.charCodeAt(i) << 8;\n else regs[regIdx] |= inv.version.charCodeAt(i);\n}\n\n\n// Serial\nfor (let i = 0; i < inv.serial.length && i < 32; i++) {\n let regIdx = 52 + Math.floor(i/2);\n if (i % 2 === 0) regs[regIdx] = inv.serial.charCodeAt(i) << 8;\n else regs[regIdx] |= inv.serial.charCodeAt(i);\n}\n\n// --- BLOCK 2: INVERTER MODEL (S101 - 1 fase) ---\nregs[68] = 1;\nregs[69] = 0xFFFF;\nregs[70] = 101; \nregs[71] = 50; \n\n// AC Waarden\nregs[72] = 0; // 40072: TotalAC Amps\nregs[73] = 0; // 40073: Phase A AC Amps\nregs[76] &= -2 ; // 40076: AC Amps SF\nregs[80] = 0; // 40080: AC Volts\nregs[83] = 0; // 40083: AC vOLTS SF\nregs[84] = 0; // 40084: AC Watts\nregs[85] = 0; // 40085: AC Watts SF\nregs[86] = 0; // 40086 AC Freq\nregs[87] &= -2; // 40087 AC Freq SF\n\n// Energy\nregs[94] = 0;\nregs[95] = 0;\nregs[96] = 0; // 40096: Wh SF\n\n\n// DC Values\nregs[97] = 0; // 40097: DC Amps (SF -1)\nregs[98] &= -2; // 40098: DC Amps SF\nregs[99] = 0; // 40099: DC Volts\nregs[100] = 0; // 40100: DC Volts SF\nregs[101] = 0; // 40101: DC Watts\nregs[102] = 0; // 40102: DC Watts SF\n\nregs[103] = 0; // 40103: Temperature\nregs[107] &= -1; // 40107 Temperature SF\n\nregs[108] = 1; // 40108 Generating power (4) or off (1)\n\nregs[110] = 0; // 40110 Events\nregs[111] = 0; // 40111 Events\nregs[112] = 0; // 40112 Events\nregs[113] = 0; // 40113 Events\n\n\n// --- Nameplate Block (Model 120) ---\nregs[122] = 120; // Model 120\nregs[123] = 26; // Length\nregs[124] = 4; // DER type = PV\nregs[125] = inv.max_w; // WRtg (watts, SF=0)\nregs[126] = 0; // Power SF = 0\n\n\n// --- Controls Block (Model 123) ---\nregs[150] = 123; // Model ID 123\nregs[151] = 24; // Length\nregs[155] = 100; // WMaxLimPct default = 100 (no limit)\nregs[157] = 0; // WMaxLimPct_RvrtTms = 0 (no auto-revert)\nregs[159] = 1; // WMaxLim_Ena = 1 (enabled)\nregs[173] = 0; // WMaxLimPct_SF = 0\n\nlet regs8bit = [];\n\nregs.forEach(num => {\n let msb = (num >> 8) & 0xFF;\n let lsb = num & 0xFF;\n regs8bit.push(msb, lsb);\n});\n\nreturn {payload : { 'value': regs8bit, 'register': 'holding', 'address': 0 , 'disableMsgOutput' : 0 }};","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":500,"y":2260,"wires":[["84679027d0b86a8e"]]},{"id":"f9d097a063c97250","type":"inject","z":"af5e2095a73fd6b0","g":"0e653fa492d095a3","name":"PV Static Values","props":[{"p":"manufacturer","v":"Growatt","vt":"str"},{"p":"model","v":"PV1 2000","vt":"str"},{"p":"serial","v":"0001","vt":"str"},{"p":"version","v":"1.0","vt":"str"},{"p":"maxwatt","v":"2000","vt":"num"}],"repeat":"","crontab":"","once":true,"onceDelay":"0.1","topic":"","x":190,"y":2260,"wires":[["d35e32def6767db0"]]},{"id":"347fea107e1f82f1","type":"modbus-client","name":"","clienttype":"tcp","bufferCommands":true,"stateLogEnabled":false,"queueLogEnabled":false,"failureLogEnabled":true,"tcpHost":"127.0.0.1","tcpPort":"5021","tcpType":"DEFAULT","serialPort":"/dev/ttyUSB","serialType":"RTU-BUFFERD","serialBaudrate":9600,"serialDatabits":8,"serialStopbits":1,"serialParity":"none","serialConnectionDelay":100,"serialAsciiResponseStartDelimiter":"0x3A","unit_id":1,"commandDelay":1,"clientTimeout":1000,"reconnectOnTimeout":true,"reconnectTimeout":2000,"parallelUnitIdsAllowed":true,"showErrors":false,"showWarnings":true,"showLogs":true},{"id":"9aaab91be38b9afd","type":"global-config","env":[],"modules":{"node-red-contrib-modbus":"5.45.2"}}]
