Measurement and analysis of the timing delay for serial port in PC
He Feng · Cehui kexue · 2009
It is essential to record the time information in dynamic surveying,which requires high precision as one of the basic observation.It is a convenient and feasible method to record the time by the serial port in PC,but the time delay should be taken into account.This paper introduces the principle of PC timing by serial port and the correlative factors which influence time delay.The inspecting method for time delay is illustrated,and then the experiments are carried out in which the influences of different correlative factors on time delay are tested and analyzed.According to the experiments,the time delay is equal to some milliseconds,which could be reduced to 0.35ms through the method of enhancing the process priority of the timing program;the influence of time delay is not evident to dynamic surveying on the condition of low velocity,and it may even be ignored in some inspecting equipments.