请教关于 DAQ PCI6221 的问题

[xiaoluge]

我今天看PCI6221的资料，发现资料上说了这么一句话：“All three ground references—AI GND, AO GND, and D GND—are connected on the device.”我就不明白为什么那三个地是连在一起的，既然连在一起，为什么不只弄一个地端（弄那么多也很麻烦的嘛，呵呵）。

[Yukee]

this remark tells that that card is not floating one.

that is available which makes many connected locations for you.

[xiaoluge]

谢谢了，你是不是说弄那么多端口是为了有更多的接线的地方，是不是啊？

还有“that card is not floating one”是什么意思啊？ 3x

[Yukee]

Yes.

let me think a channle to explain for you.

if the device is floating one ,example a "Scope", then ,it can test our AC voltage's waveform or the other parameter.

if not floating (share earth ground). it cann't be. high voltage will burn away the device. 

[xiaoluge]

呵呵，谢谢了

[yulzhu]

其实这个问题很简单

你找到这块卡的user manual

里面都它的结构图