"# VisualHMI USB HID \u626b\u7801\u67aa\uff1aon_key \u626b\u63cf\u7801\u8f6c ASCII\n\n> 2026-08-04 | 2026-08-04\n> http:\/\/www.modbus.cn\/en\/51602.html\n\n**\u4e32\u53e3\u5c4f\/HMI \u5f00\u53d1, \u5176\u4ed6\u6280\u672f\u8d44\u6599**\n\n---\n\nUSB Host + \u5b9a\u5236\u56fa\u4ef6\uff0c\u76f4\u63a5\u63a5 HID \u6761\u7801\u626b\u63cf\u67aa\uff0c\u626b\u7801\u5185\u5bb9\u7ecf on_key(key) \u56de\u8c03\u8fdb Lua\u3002\u5de5\u4e1a\u4ed3\u50a8\u3001\u4ea7\u7ebf\u8ffd\u6eaf\u7528\u5f97\u7740\u3002HMI&M&DX \u7cfb\u5217 + USB \u63a5\u53e3 + \u5b9a\u5236\u56fa\u4ef6\u3002\n\n## 1. API\uff1aon_key(key)\n\nkey \u4e3a 16 \u4f4d\u65e0\u7b26\u53f7\u6574\u6570\uff1a\u4f4e 8 \u4f4d = USB HID Usage ID\uff08\u626b\u63cf\u7801\uff09\uff0c\u9ad8 8 \u4f4d = Shift \u72b6\u6001\uff08\u975e 0 \u8868\u793a Shift \u6309\u4e0b\uff0c\u533a\u5206\u5927\u5c0f\u5199\uff09\u3002**\u4f4e 8 \u4f4d == 0x28\uff08Enter\uff09\u8868\u793a\u6761\u7801\u7ed3\u675f**\uff0c\u6b64\u65f6\u63d0\u4ea4\u5b57\u7b26\u4e32\u5e76\u6e05\u7a7a\u7f13\u51b2\u3002\n\n## 2. Lua\uff1aHID \u626b\u63cf\u7801\u8f6c ASCII\n\n\u7528\u67e5\u8868\u628a Usage ID \u6620\u5c04\u6210\u5b57\u7b26\uff08\u542b Shift \u5927\u5199\u6001\uff09\uff0c\u9047\u5230 0x28 \u7ed3\u675f\u7b26\u5199 LW2000\uff1a\n\n```\n_barCode = \"\"\nusbScanGun = {\n  [0x04] = {\"a\",\"A\"}, [0x05] = {\"b\",\"B\"}, ... [0x1D] = {\"z\",\"Z\"},\n  [0x1E] = {\"1\",\"!\"}, [0x1F] = {\"2\",\"@\"}, ... [0x27] = {\"0\",\")\"},\n  [0x2C] = {\" \",\" \"}, [0x28] = {\"n\",\"n\"}  -- Enter\n}\nfunction on_key(key)\n  local usage = key & 0xFF\n  local shift = (key >> 8) & 0xFF\n  if usage == 0x28 then        -- \u7ed3\u675f\u7b26\n    set_string(VT_LW, 0x2000, _barCode)\n    _barCode = \"\"\n    return\n  end\n  local ch = usbScanGun[usage]\n  if ch then\n    _barCode = _barCode .. (shift ~= 0 and ch[2] or ch[1])\n  end\nend\n```\n\n\u626b\u7801\u67aa\u672c\u8d28\u662f**\u952e\u76d8\u6a21\u62df**\uff1aHID \u4e0a\u62a5\u7684\u662f\u626b\u63cf\u7801\u4e0d\u662f ASCII\uff0c\u5f97\u81ea\u5df1\u67e5\u8868\u8f6c\u3002Shift \u72b6\u6001\u5728 key \u9ad8 8 \u4f4d\uff0c\u5927\u5c0f\u5199\u9760\u5b83\u533a\u5206\u30020x28 \u662f\u56de\u8f66\u7ed3\u675f\u7b26\u2014\u2014\u6536\u5230\u5c31\u63d0\u4ea4\uff0c\u522b\u7b49\u8d85\u65f6\u3002\u5b9a\u5236\u56fa\u4ef6\u4e13\u5c5e\u3002\n\n\u6574\u7406\u81ea \u5e7f\u5dde\u5927\u5f69\u79d1\u6280 VisualHMI \u5f00\u53d1\u6587\u6863\uff08hmi-doc.gz-dc.com\uff09\u5176\u4ed6\u6280\u672f\u6559\u7a0b\u300cUSB HID\u626b\u7801\u67aa\u300d\uff0c\u7248\u6743\u5f52\u5927\u5f69\u79d1\u6280\u6240\u6709\u3002\n\n---\n*modbus.cn*\n"