... voltage warning, automatic shutdown. GLZ-B model adopt RS232 interface, extract datum and import EXCEL for graphics, analysis software ... Computer Communication: USB1.1 Model difference:ModelDifferenceGLZ-AWithout computer interface, can only store the data on the mainframeGLZ-Binterface, ... import data into the computer to enter data processingCLZ-C Interface, RS-485 double way recorder, can record PAR ...