This data logger can measure and store DC Voltage readings automatically. The professional applications can be provided by the PC software DGraphTM. Logger status, alarm indication and low battery indication are via flashing red/green LED and yellow LED. The button on housing can be used to start logging, or confirm and clear LED alarm when LED alarm is hold status. User can plug data logger straight into PCs USB port without any cables. Before getting started, user need to install USB driver and DGraphTM software, provided on the CD which is included in product packing box. All the software can run under Windows XP, Vista, 7 or 8(32 bit and 64 bit Versions). User can easily use DGraphTM software to setup sample rate, high/low alarm limit and start/stop method, and download data to PC, etc.. And then user can view, analyse and print the data, or export other file formats(txt, xsl, csv, bmp, jpg). Especially, for some professional applications, user can set access password, name each channel, enable/disable specified channel, input calibration data for each channel, disable LED indication for saving power, and select sample mode(Instant, Average, Maximum and Minimum), etc.. Portable, precise, compact and low cost; Easy to log and analyse data Unique and uniform PC software DGraphTM can meet your higher requirements Elaborate design make it perfectly work in more application field Strict design ensure long term reliable work Enhanced electrostatic protection design to prevent unexpected damage. Each unit have single serial number identified by DGraphTM software to manage data simply All data from different data logger and all different measurement parameters can be graphed and analysed together. FEATURES: USB interface directly communicate with PC for setup and data download, user can set access password for data logger; User can name each channel and enable/disable specified channel freely LED alarm enable/disable, LED alarm hold enable/ disable and alarm limit settings for all channels via DGraphTM User can input formula to customize compound line; User can create and customize new unit easily and freely; Logging status indication via red/green LED and battery status indication via yellow LED; Start logging method: Immediately, button and delayed; User can input two point calibration value for each channel when setup; Replaceable lithium battery and logged datas will not lost if battery exhausted