Hi,I am using a NI PCI-6221 card to output a voltage step by step to change the wavelength of a laser,at each voltage step,I use a GPIB card on the PC to get some data points and then average them,at the same time the PC reads datas from a RS232 port.After finishing that,the voltage goes to the next step till I stop the VI manually.
Normally the VI should always run at the same speed,and it did last night when finished it.But today it runs quite fast at first,and then slow down to the normal speed as last night.For example I want to get 100 points after averaging,now the VI get the first 50 points quite fast and then it slows down to a normal speed to get the rest 50 points.And what is bad is the first 50 points seems wrong,because the wavelength does not change.
I am new to Labview.I guess there are some data buffers for the GPIB and RS232,so when I stop the VI,the data continue written into the buffer,so when I run the VI again,the VI read data points from the buffers instead of the card ports,so it runs quite fast at first and when the buffer is clear it slow down.Am I right?
I want the VI run step by step stablely.So how to deal with such case?Anyone kind can help me?Thanks in advance!
帖子被coz在
01-01-2008 01:58 AM时编辑过了
