We have an Agilent U1620A Scopemeter, and can't get the data logger to start in scopemode (It works in DMM mode).
According to the manual, it should start to log immediately. It doesn't, and it shows no graphs or measurement values. It does not react to the "Run/Stop" button either.
We updated to firmware 0.150.9, but that didn't help.
What are we doing wrong?
According to the manual, it should start to log immediately. It doesn't, and it shows no graphs or measurement values. It does not react to the "Run/Stop" button either.
We updated to firmware 0.150.9, but that didn't help.
What are we doing wrong?
It appears that if there is no signal present on the input, the logger (in scope mode) will not start. Following the directions in the manual results in no logging, no display, no stats, etc. This is often the case if you are just experimenting with the scope to become familiar with the capabilities and don't have a signal source connected to one of the input channels.
I was about to call Agilent support when I thought that perhaps it required at least some minimal input signal to trigger. So I connected a square wave @ 600 Hz and 4V -- and bingo -- it recognizes the input and begins logging. I plotted frequency vs. time in this case.
Bottom line, you need some kind of input signal to trigger it to wake it up in scope mode. This is not the case for the DMM mode where even with no leads connected, it will register values and allow you to begin logging, even if it's just noise or zero ohms...
Is this a bug? Or a feature? Hard to know. What's not clear is what the minimum threshold is to recognize something on the input -- I'll run some tests with a simple DC offset to see if that's enough to wake it up or whether it requires some kind of AC signal of a certain amplitude. In either case, the manual could be more clear on this point stating what the minimum input conditions are (based on the probe used) to allow logging to commence. Without this, I agree it appears that the unit is broken or doesn't work right...particularly if you're just becoming familiar with the U1620A. Hope this helps.
Therefore in order to start the data logger in scope mode, you need to select the measurement in the Scope screen, for example 'Frequency".
After that, when you go to logger mode you will able to start the data logging in the Scope mode.
I hope this helps.
1) First, I tried this many times and "thought" I had a measurement selected. There is an important (and subtle) distinction between selecting a measurement (e.g. Frequency, V or AVG, etc) and then pressing the "SELECT" softkey again to select it -- but then in a 2nd step, pressing the "MEASURE" softkey to actually cause the selected measurement to be active for logging purposes. Therefore, although the Freq measurement in this case was indeed "SELECTED", it wasn't "active"...hence there was nothing to measure or log.
2) My suggestion is two-fold:
(a) At the very beginning of the Section 5 of the User Guide (page 86 of this document: http://cp.literature.agilent.com/litweb/pdf/U1610-90040.pdf ), there should be a bold warning that states: "You must first select and activate a measure function before logging can start". The starting point of this instruction assumes that you can just press the LOGGING softkey and begin logging when, in fact, you cannot begin logging unless you first go through the setup process of selecting a measurement. It's true that later in this section, this point is briefly mentioned, but I think putting it up front would help avoid confusion.
(b) Since some people may not have the manual nearby, the U1620A could easily pop up a warning similar to "Scope Logging Mode is Disabled Until a Measurement is Activated. Please go back and activate a measurement"
Also, what makes this confusing is that in the case of the DMM logging, it starts immediately without having to select a measurement -- to the behavior is different between the two, which adds some inconsistency in the UI. Again, this can be addressed with a simple warning message on the U1620A screen and in the manual at the start of section 5.
3) The other point that I think needs a little more clarification in the manual is this: I had two measurements selected for Channel 1, and when in the scope logging mode, I could not see a way to measure Channel 2. After re-reading the manual again, it refers only to two measurements. I then surmised that if you want to view Channel 2, you must go back and deactivate at least one of the Channel 1 measurements which is effectively consuming all 2 logging channels. Once I did that, I was able to split the logging measurements between Channel 1 and Channel 2. I believe that the manual could make this more clear (particularly if you're trying to log between Channel 1 and Channel 2.
However, I could also find it very helpful in the LOGGING menu area to allow you to select any of the 2 measurements structured between Channel 1 and Channel 2. This would save a lot of hassle having to reset or disable measurements which you may want to retain in SCOPE mode.
Let's use an example to make this more clear:
1) Suppose I'm measuring FREQ and Vp-p on CH1 and CH2. We'll call these FREQ(1), Vpp(1), FREQ(2), Vpp(2)
2) I can see all 4 of these on the bottom of the screen in SCOPE view mode.
3) Now I decide I want to log CH1 and CH2.
4) Currently, if I press LOGGING, it automatically starts to log only FREQ(1) and Vpp(1). There is no way to log FREQ(2) or Vpp(2) without going back and clearing the measurements on all the channels and selecting again what I want to log. This is a lot of work, especially when flipping back and forth between SCOPE and LOGGING modes.
5) My suggestion is that when you are in the LOGGING menu, there is a softkey that allows you to ROTATE between the available unique combinations so you can log the specific measurements you want _without having to reset the measurements in SCOPE mode_.
Pressing the SELECT LOGGING MEASUREMENT key would rotate as follows:
FREQ(1), Vpp(1)
FREQ(2), Vpp(2)
FREQ(1), FREQ(2)
Vpp(1), Vpp(2)
FREQ(1), Vpp(2)
FREQ (2), Vpp(1)
.... and through all the combinations in case I missed any ...
Of course, there are other implementations that could achieve a similar result -- but the key message here is that with a minor enhancement, it would greatly improve the user experience and make logging measurements more efficient.
Additional Feedback
Some other features related to logging that would be very welcome are:
1) Allow user to set logging interval other than 1 second.
(a) Less than 1 second is helpful for capturing transients -- how fast can you go without overtaxing the CPU/display?
(b) Longer than 1 second is helpful for measurements that don't change fast, and it reduces the amount of data while extending the logging duration. For example, maybe I want to log temperature for 1 month. I may only need a data point every 10 seconds or 1 minute, especially if there is a long thermal lag on the thing I'm measuring. I would see the UI offering obvious steps, such as 1, 2, 5, 10, 15, 30, 60 seconds -- and then 2, 5, 10, 30, 60 minutes -- and then hourly increments up to 24 hours -- or allow a user-defined interval.
(c) I haven't verified yet if the logging measurements are time-stamped in the output file, but if not, they should be.
2) Allow trace color selection between the 2 logging channels
3) Consider allowing 4 logging channels (2 measurements/scope input)
4) Allow user-settable scales on logging output (particularly vertical range). Right now it autoranges, which is fine -- but sometimes you want to compare two graphs using the same scale and being able to force the vertical min/max/center to a specific set of values is very important. Another reason is that sometimes you may have a small glitch when connecting a cable -- and it can distort the entire logging range by compressing the data you want to see. So having a user settable vertical scale is very important in any logging situation.
I have many other ideas/suggestion for how to improve the U1620A user experience and would welcome the opportunity to speak directly to the product management team responsible for this product line. Please send me a direct message via the forum with your contact information and we can continue this offline. Thank you!