hp816x无法自动设置功率传感器电源模式

嗨aagne***，谢谢你的询问。
您所看到的是当用于以这种方式记录数据时功率计的正常限制。
自动量程模式中使用的量程切换需要时间，并且可能与采样触发时序冲突。
大多数情况下，采样的触发速度比可以实现的范围切换更快。
因此，此应用程序不支持自动量程。
默认情况下，MFlambdascan功能+ prepareMFlambdascan +将设置足够高的功率范围，以测量设置中可调谐激光器的功率水平。
如果已知最大测量功率将较低，则可以使用+ setInitialRangeParams +功能更改此范围设置，例如由于激光器和功率计之间的路径中的插入损耗。
使用较低功率范围的优点是，这还允许通过降低噪声水平来测量较低的信号电平。
因此，测量的动态范围受到低侧噪声水平和高侧最大可测量功率的限制。
最大水平通常是范围标称值的两倍。
因此，在-10dBm功率范围内，可以测量到-7dBm的最大电平。
为了在测量中获得更高的动态范围，例如测量带内低插入损耗和带外衰减的带通滤波器，MFlambdascan函数具有+ numberofScans +的参数。
当设置为2或3而不是1时，波长扫描以较低的功率范围重复（默认情况下为20dB，可以使用+ setInitialRangeParams +更改）并使用最佳扫描将扫描“拼接”在一起
每个波长点。
如果您想要获得更高的动态范围，这可能是您想要使用的。
一些功率计，81636B，N7744A和N7745A也设计用于提供特别宽的动态范围，同时记录单一功率范围设置。
我希望这有助于理解这些功能是如何工作的。
最好的问候，迈克



     以下为原文

  Hi aagne***,
Thanks for asking. 
What you are seeing is the normal limitation of the power meters when used for logging data this way. The range switching that is used in autorange mode takes time and can conflict with the sample triggering timing. Most often the sampling is triggered faster than the range switching can be achieved. So autoranging is not supported in this application.
By default the MFlambdascan function +prepareMFlambdascan+ will set a power range that is high enough to measure the power level set for the tunable laser in the setup. This range setting can be changed with the +setInitialRangeParams+ function if it is known that the maximum measured power will be lower, for example because of insertion loss in the path between laser and power meter. 

The advantage of using a lower power range is that this also allows measuring lower signal levels by reducing the noise level. So the dynamic range of the measurement is limited by the noise level on the low side and the maximum measurable power on the high side. The maximum level is typically twice the nominal value of the range. So in the -10dBm power range for example, a maximum level of -7dBm can be measured.
To obtain a higher dynamic range in a measurement, like for measuring bandpass filters with low insertion loss in-band and very attenuation out of band, the MFlambdascan function has the parameter for +numberofScans+. When this is set to 2 or 3 instead of 1, then the wavelength scan is repeated with decreased power range (in steps of 20dB by default which can be changed with +setInitialRangeParams+ ) and the scans are "stitched" together using the best scan for each wavelength point. This may be what you want to use if you are trying to get a higher dynamic range.

Some of the power meters, the 81636B, the N7744A and the N7745A are also designed to provide especially wide dynamic range while logging in a single power range setting.

I hope that helps understand how the functions are working.

Best regards,
Mike

嗨迈克，谢谢你的回答。
我将研究关于扫描2和3的数量，范围减少，初始范围的关系。
今天我发现其他问题，我使用MFlambdascan测试自动扫描，我只使用81680a可调谐激光器和81636B功率计之间的光纤连接，激光功率设置低功率0dBm。
当我扫描小范围（例如1540到1541nm，步长0.01nm），然后扫描结束，激光停止在1541nm，我看到功率计显示为-5.12dBm，然后我看到我的计算机的MFlambdascan显示1541nm = -
5.12dBm，功率计显示和MFlambdascan匹配。
当我扫描大范围（例如1500到1541nm，步长0.01nm），然后扫描结束，激光停止在1541nm，我看到功率计显示为-5.12dBm。问题来了，我看到我的电脑的MFlambdascan
显示1541nm = -6.75dBm，功率计显示与MFlambdascan不匹配，顺便说一下，扫描范围大到1500到1541nm，MFlambdascan将显示大于-6.75dBm。
通常吗？
最好的问候，aagne***



     以下为原文

  Hi mike,
Thanks for your answer.

I will research relations with numberofScans 2 and 3 ,range decrement,initial range. 



Today i find other question,i use MFlambdascan to test auto sweep,and i just only use fiber connect between 81680a tunable laser and 81636B power meter,and laser power setting low power 0dBm.

When i sweep small range(ex. 1540 to 1541nm,step0.01nm),then sweep is end,the laser stop at 1541nm,and i saw the power meter display is -5.12dBm,then i saw my computer's MFlambdascan display 1541nm=-5.12dBm,the power meter display and MFlambdascan is match.

When i sweep large range(ex. 1500 to 1541nm,step0.01nm),then sweep is end,the laser stop at 1541nm,and i saw the power meter display is -5.12dBm.The question is coming,i saw my computer's MFlambdascan display 1541nm=-6.75dBm,the power meter display and MFlambdascan is not match,by the way,the sweep range is large then 1500 to 1541nm,the MFlambdascan will display bigger then -6.75dBm.
Is it normally?



Best regards,
aagne***

这是一个很好的观察，但它应该是我们所期望的。
与1540nm相比，激光器在1500nm处具有更低的最大功率。
因此，从1500nm开始的扫描需要使用较低的功率水平。
扫描运行时，激光器使用在所选波长范围内可达到的最高功率（达到所选功率水平）。
它调节自身以在扫描期间保持该水平恒定。
当你的激光在1541nm处停止时，听起来就像扫描一样，它恢复到设定的功率水平。
这看起来适合你所看到的吗？



     以下为原文

  That's a good observation, but it should be what we expect. The laser will have a lower maximum power at 1500nm compared to 1540nm.
So a sweep that starts from 1500nm needs to use a lower power level. When the sweep is run, the laser uses the highest power that it can achieve over the chosen wavelength range (up to the selected power level). It regulates itself to keep that level constant during the sweep. It sounds like after the sweep when your laser stopped at 1541nm, that it returns to the set power level. Does that seem to fit what you see?

哦迈克！
你是我的救星，帮我解决很多问题。
我问***安捷伦8164a的问题，他们总是告诉我他们不支持的仪器，相比之下，你的服务是如此完美。
顺便说一句，我想为8164a改进一些东西，希望你能给我一些想法，非常感谢。
我想使用可调谐激光扫描和功率计立即获得功率值，可以立即绘制波形，但我没有找到最好的想法，我会解释我的想法。
1.使用命令改变激光波（sour0：wav？nm）并读取功率计的值（fetc1：pow？）进行for循环，激光波长将加i，这个想法很慢。
2.使用扫描命令让它自动扫描，并继续读取功率值，这个想法将改善idea1问题，但最低扫描速度（500pm / s）对我这么快，我只读了70％数据，是否有
任何触发命令让功率计输出继续？不是我输入命令反馈功率值。
非常感谢你。
祝贺，aagne***编辑：kai.chang于2014年1月22日上午2:57



     以下为原文

  Oh mike!
You are my lifesaver,help me solve much problem.
I ask the 8164a's problem with taiwan agilent,they always tell me that Instrument they don't support,In contrast your service was so perfect.

By the way,i want improve something for 8164a,hope you give me some idea,thanks a lot. 
I want use tunable laser sweep and power meter get power value immediately,that can right away drawing waveform,but i didn't find a best idea to do,i will explain my idea.

1.Use the command change the laser's wave(sour0:wav ?nm) and read power meter's value(fetc1:pow?) in for loop,the laser wavelenght will add with i,this idea was slow.

2.Use the sweep command let it auto sweep,and continue to read power value,this idea will improve idea1 question,but lowest sweep speed(500pm/s) was so fast with me,i just read 70% data,

Is that have any trigger command let power meter export continue?not i enter a command feedback a power value.

Thank you very much.

Congratulation,
aagne***

Edited by: kai.chang on Jan 22, 2014 2:57 AM

嗨aagne***，谢谢，这是一个讨论使用这些产品的好地方，因为编程也与我们现有的产品兼容。
据我了解，您希望在激光波长扫描时实时上传各个功率值。
这通常不是优选的，因为它限制了测量速度与制作GPIB命令的速率，并且还需要PC的持续关注。
因此，通常功率计用于在扫描期间记录所有样本，然后在扫描之后，可以上载功率值集和来自激光记录的波长值集。
这就是MFlambdascan功能在816x PnP驱动程序中的作用。
顺便说一句，如果你还没有尝试过，有一个免费的GUI软件，可以通过这种方式使用PnP驱动程序。
您可以在此处获取：[www.agilent.com/find/n7700]您需要安装主N7700A软件包和IL Engine软件包以及您已有的PnP驱动程序。
无论如何，如果你需要读取各个值，那么在GPIB上发送命令和数据的速率将是速度限制。
您可以通过写一个短循环来重复发送FETCH命令并读取响应来检查该速率。
8164A主机的速度比较新的8164B慢。
考虑到这种速率限制，我认为您最好使用这些命令进行激光的步进扫描，而不是为每个波长步骤发送单独的命令。
然后，您可以将激光编程为在每个波长下保持所需的时间，然后再继续，并且可以在每个步骤完成时为功率计提供触发。
您需要将主机触发系统配置为“环回”或“反馈”，以便激光器的输出触发器输入到功率计。
然后应禁用功率计的连续触发，+ init：cont 0+，并配置功率计的输入触发器以在触发时进行测量。
然后应该可以使用fetch命令收集每个读数，尽管我不确定什么是从PC计时命令的最佳方法。
在任何情况下，使用PnP驱动程序也可以更容易地编写这些类型的命令。
本主题中描述了类似的程序，但这也是使用功率计记录而不是单独读取每个值。
8163B - >可调谐拉伸的步进波长测量
祝你好运！
麦克风



     以下为原文

  Hi aagne***,
Thanks, this is a good place to discuss using these products since the programming is compatible with our current products too.

As I understand it, you are hoping to upload the individual power values in real-time while the laser wavelength scans.
That isn't usually preferred because it limits the measurement speed with the rate of making GPIB commands and also requires pretty continuous attention from the PC. 

So usually the power meter is used to log all of the samples during the scan and then after the scan both the set of power values and the set of wavelength values from the laser logging can be uploaded. That is what the MFlambdascan function is doing in the 816x PnP driver. By the way, if you haven't yet tried it, there is a free GUI software available that uses the PnP driver this way. You can get it here:
[www.agilent.com/find/n7700]
You will need to install the main N7700A package and the IL Engine package along with the PnP driver that you already have.

Anyway if you need to read the individual values as they come, then the rate of sending commands and data on the GPIB will be the speed limitation. You could check that rate by writing a short loop to repeatedly send the FETCH command and read the response. This speed will be slower with the 8164A mainframe than with the newer 8164B.

Considering this rate limitation, I think you could best use the commands for stepped sweeps of the laser instead of sending a separate command for each wavelength step. Then you can program the laser to stay at each wavelength for the necessary amount of time before continuing and it can give a trigger to the power meter when each step is complete.  You need to configure the mainframe trigger system to "loopback" or "feedback" so that the output triggers from the laser are input to the power meter. Then the continuous triggering of the power meter should be disabled, +init:cont 0+ , and the input trigger of the power meter configured to measure when triggered. It should then be possible to collect each reading with a fetch command, although I'm not sure what will be the best way to time the commands from the PC.

In any case, these type of commands may also be easier to write using the PnP driver. A similar program is described in this topic, but this is also using the power meter logging instead of reading each value separately.
8163B -> stepped-wavelength measurements with tunable las
 

Good luck!
Mike