The resistances of seven wind tunnel model shelterbelts were determined with platform balance. The resistance coefficient was C_α = l6.3 (1-α)~(0.55) when the shelterbelt structure was expressed as ventilation, and which was C_β = 14.0 when shelterbelt structure was expressed as sparisity.
During the system program and structure design, through accurate calculating and strict reasoning, and taking PLC as control center, we accomplished the communication between PLC and electronical platform balance, realized the function of weighing up cannon-pot automatically, made judgement of the gained weight and gave relevant alarm sigal;
This kind of the electronical platform balance is equipped with peripheral of 7211AM,74C922 intelli- gentized chip and Watchdog circuit. the method is efficient,cred- ible, precise and absolutely accord with the design requirement.