[问答]

33401A万用表读取电压读数太高

问答对人有帮助，内容完整，我也想知道答案 0 您好，我可以使用一些帮助解决问题。首先是一点背景：我的公司要求我自动进行一些测试，但我没有这方面的经验。我正在学习，到目前为止已经取得了一些成功。我正在使用一些Agilent 33401A万用表以及一些较新的Agilent万用表。我正在使用labview进行软件控制。我的问题在于33401A万用表。我在新的数字万用表上以同样的方式挂钩所有内容并且没有遇到此问题。我把V +，LO和I（当前）终端连接起来了。我有我的软件连接并进行测量。一切都正确读取，直到我切换到读取电压。当我这样做时，电压读数太高，因此输入功率增加。在约500mA的电流下，电压读数约为1.6V。一旦切换回当前读数模式，输入功率就会下降到应有的状态。所以这个问题很可能出现在电压测量中。我知道数字万用表会有一些负载，但这些万用表似乎不合理。同样，这不会发生在与我的新DMM完全相同的设置中。是否有任何我可以更改的设置或我可以做的任何事情来帮助将此负载降低到更合理的水平？我试过改变测距和分辨率无济于事。当我切换到电压读数模式时，问题总会出现。对不起，我的经验不足，我很感激任何帮助！德鲁以上来自于谷歌翻译以下为原文 Hello, I could use some assistance fixing an issue. A little background first: my company is asking me to automate some testing but I have no experience doing so. I am learning as I go and so far have found some success. I am using some Agilent 33401A multimeters as well as some newer Agilent multimeters. I am using Labview for the software control. My problem is with the 33401A multimeters specifically. I hook everything up the same way on my newer DMMs and do not experience this issue. I have the V+, LO, and I(current) terminals hooked up. I have my software connect and take measurements. Everything reads correctly until I switch to read voltage. When I do this the voltage reads too high and my input power is therefore increased. The voltage is reading about 1.6V high on about 500mA of current. As soon as I switch back to current reading mode the input power drops back down to where it should be. So the issue is likely somewhere in the voltage measurement. I understand that there will be some load by the DMM but it seems to be unreasonably large with these multimeters. Again, this does not happen in the exact same set up with my newer DMMs. Are there any settings I can change or anything I can do to help bring this loading down to a more reasonable level? I've tried changing the ranging and resolution to no avail. The problem always comes back when I switch to voltage reading mode. Sorry for my inexperience, I'd appreciate any help! Drew 0
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答案对人有帮助，有参考价值 0 问题是由34401A上同时使用电流和电压输入引起的。在34401A的电压模式下，Lo插孔承载DUT电压的电流AND负电位。这已经在仪器内部的负路径上，即在PCB路径上和前/后开关中产生电压降。今晚我已经检查了当前频道会发生什么，如果你切换到DCV。在DCI模式下，34401A处于1A范围，即使用其内部0.1欧姆分流电阻。如果切换到DCV，则使用其内部5欧姆分流电阻将电流范围切换为10mA。 500mA电流依次使分流器过载，因此二极管保护网络将被激活。它由两个二极管组成，它们将负载限制在大约1.2V，加上电流路径上的一些电压降，这相当于您观察到的1.6V。在此配置中不应使用此仪器，以避免因此永久性过载而造成的损坏！较新的TrueVolt数字万用表（如34460,461,465,470）表现不同。它们总是在DCV模式下切换到3A电流范围，因此没有过载。无论如何，如上所述，仍会存在内部电压降，这会产生一些误差。请在您的设置中使用两个不同的DMM。 Frank编辑：Dr_Frank于2015年10月13日上午3:23完全重写了这篇文章，由于之前的测试。以上来自于谷歌翻译以下为原文 The problem is caused by the simultaneous usage of current and voltage input on the 34401A. In voltage mode of the 34401A, the Lo jack carries the current AND the negative potential of your DUT voltage. That already creates a voltage drop on the negative path inside the instrument, i.e. on the PCB path, and in the front/rear switch. Tonight I've checked what happens with the current channel, if you switch to DCV. In DCI mode, the 34401A is on the 1A range, i.e. using its internal 0.1 Ohm shunt resistor. If you switch to DCV, current range switches to 10mA, using its internal 5 Ohm shunt resistor. The 500mA current in turn in overloads the shunt, so the diode protection network will be activated. This consists of two diodes, which limit the burden to about 1.2V, plus some voltage drop on the current path, which adds up to the 1.6V you observe. You should not use this instrument in this configuration, to avoid damage caused by this permanent overload! The newer TrueVolt DMMs like 34460, 461, 465, 470 behave differently. They always switch to the 3A current range at DCV mode, so that there is no overload. Anyhow, there will still be an internal voltage drop, which gives some error, as described above. Please, use two different DMMs in your setup. Frank Edited by: Dr_Frank on Oct 13, 2015 3:23 AM Completely re wrote the article, due to previous testing.

2018-9-20 11:35:13 评论举报宋阳