High-Frequency Volume Ratio (VR)

Query intraday minute-bar VR (Volume Ratio) for A-share securities via the market data service.VR = (up_volume + 0.5 * flat_volume) / (down_volume + 0.5 * flat_volume) * 100.Default period N=26. VR > 450 overbought, VR < 40 oversold.codes: comma-separated security codes (e.g. '600000.SH,000001.SZ').interval: minute bar width — 1/3/5/10/15/30/60.starttime/endtime: 'YYYY-MM-DD HH: MM: SS' intraday range.