I-V curve scan

The I-V curve scan sweeps the PV input and records the current-voltage characteristic of the connected strings, so faults, damage or installation errors in the array can be found without a separate tracer. Sunny Tripower CORE1-US inverters measure one curve per MPPT input, so strings in parallel on that input show up as one combined curve, and the measured current cannot exceed the MPPT input current rating. On the CORE1-US, each scan briefly stops feed-in and runs the inverter at reduced power for about 20 seconds per MPPT input, and it can run at most 10 times per day unless the inverter is restarted. CORE1 results have over 200 data points per input, are stored until the next scan, can be saved to PDF, and show temperature and irradiance when the optional SMA Sensor Module is fitted. The function is listed for STP 33/50/62-US-41 from firmware 03.12.21.R, and the table lists firmware as not available for STP 50-US-40. On Canadian Solar CSI and Solis three-phase inverters, you set Start_V and Interval_V in the I/V Curve menu, then press ENT to start the scan. The display shows Scan OK when it finishes, and you then pick a string number to view its results. These CSI and Solis inverters record 60 data points per scan, and some models state a maximum scanning range of 100-1450V or 850-1450V. CPS inverters can start a scan over Modbus by writing 0xA801 to register 0x2B12. Reading the same register returns whether the scan is in progress, finished or failed. The Sunny Tripower X 12 to 25 datasheet lists I-V generator diagnostics as a feature.

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• sentence 1: support check: partial - Scan of I/V curves per string and deviations indicating faults/errors are stated, and no extra measurement devices needed; but 'sweeps PV input' is paraphrase and it's mixed across products, mostly fine though 'damage' etc. are covered. -->