Unable to change X-axis values in playback

[EdBye]

I need help with an issue in SignalExpress which I am new to and struggling a bit.

In PlayBack mode DisplayView I can’t get the X-Axis to retain the values I set. I can change them but as soon as I click ‘play’ the max value alters to what appears to be the buffer length of the recorded data, the on screen, AutoScale is off. The play-position indicator shows that I have more data than one buffer length and exporting the log file to Excel confirms that all the data (greater than one buffer in length) is there.

Regards

ed

[mickeyw]

Hi Ed,

Many thanks you using the National Instruments forums. How exactly are you setting the axis? Are you saving the programme before playing it? If you have access to LabVIEW, do you see the same issue when you convert the signal express programme into LabVIEW code?

Many thanks,

[EdBye]

My Mike,

Thanks for replying and giving suggestions.

I don't have Labview but could get evaluation version if you think this might help. I would be even less familiar with this than SignalExpress so the effort might not be worth it.

I have tried pre and post saving to set the x-axis, the results are the same. It looks like the values I set in the x-axis are overwritten by values within or associtaed with the recorded/saved file and I feel I must be missing something simple. I tried the help function and as far as I'm aware I'm following the information necessary.

What I do is  set signal express to playback mode and in dataview having dragged my voltage logged file to the graph I right click and select 'properties' - 'scales'. for the 'time' option I uncheck autoscale andalter the max value to 300 ( I have 300 sec of recorded data) and click 'ok'. My data view graph changes x-axis to 300 max and a small ammount of data is compressed at the left hand side of the graph. I then click play at the top and the x-axis changes to 10 sec. The bar at the top shows 300s and scrolls though with what apperas to be just evry 10s of data (block) being displayed on the main graph.

If I then check 'properites' for the x-axis as above, auto sclae is still unchecked and max value reads 9.9s. I can change this and the graph x-axis changes until the next block gets placed on the screen where the x-axis reverts to 10s. After I make this change my data of unkown block gets compressed to the first 10s at the left, it fills the graph once updtae occurs but only the current (I assune) block.

if I look at 'playback options' I see nice little images of my data over 300s  with start time 0 stop time 300 relative to log start time, block size 1000, overlap 0%, ignore last itteration if partial is checked and play entire intervals only is not checked.

I set the record side up for sampling 100Hz with block size 1000.

Hope this information helps you understand what is going on and that you can tell me what I've missed.

Kind regards

Ed Bye

[Phil_J1]

Hi Ed,

You're right that this appears to be an issue in SignalExpress. I tried your instructions with both a scalar on a chart and a waveform on a waveform graph and both seem to reset to the data's bounds instead of the user set bound, even when autoscale is off. I'll take a closer look into why that is.

Just to be clear, are you trying to see your entire log? Or are you trying to do some post-processing on your log after having recorded it? Playback is designed for the latter; playback will play your log back in chunks (as defined by the playback optioned you also mentioned) which is what you are seeing when you press the run button. If you add more step to the project while in playback mode, the steps can use the log as an input.

If you're trying to view your whole log and possibly zoom into it and analyze it manual and visually, it's currently recommended that you do that in the Record/Monitor mode. All you have to do is drag the log you want from the Log Area (located in the bottom left of the application) into the main Data View. The whole log should apprear there and you should be able to view it.

Phil

[EdBye]

Hi Phil

Thanks for your speedy reply.

I spent hours trying to figure out what i was doing wrong, putting it down to the learning curve. I think I'm pleased to discover its a bug and not me.

I hadn't got as far as trying to do analyis just want to scroll trhough and magnify entire log.

tried your suggestion re record/monitor mode, now I have no time (X-axis) display  on the main graph when I check propertiesmin and max values have hugh numbers which I guess is the internal representation of the actual/sytem date & time on the small graph undeneath, is there a way to get the scale to display on the main graph as changing the min/max values don't work - scale reverts to blank or off as soon as the cursor9s) are moved. 

Also is there a way to change the time format to 'start of log'.

Hope you can help with these points.

regards

Ed

[Phil_J1]

Hi Ed,

I'll answer in steps.

1. "now I have no time (X-axis) display on the main graph".

I'm not sure what you mean by that, a screenshot would be very helpful. The x-axis should say "Time (s)" under the scale values. Your scale values should be from a min that is represented as a time, and so should the max, by default.

2. "when I check properties min and max values have hugh numbers which I guess is the internal representation of the actual/sytem date & time on the small graph undeneath"

That is absolutely correct - it's called a Timestamp; what you see is a system date & time (timestamp) as a floating point number. (I know what you are thinking)

3. "Also is there a way to change the time format to 'start of log'."

Kind of. By right-clicking the graph, and selecting Timestamp >> Ignore Timestamp. This will set the graph to display the start of the log as time = 0, instead of the actual date and time. So if your log is 300 secs long, the scale will read 0 to 300s. Now going back to comment #2, when you are in Ignore TImestamp mode, the property page should show min and max of 0 and 300 respectively.

4. "scale reverts to blank or off as soon as the cursor9s) are moved."

I assume this is related to comment #1, and that you manually set axis labels, but when you zoom in or out, the scale get reset to blank; is this what you are saying?

Also what version of SignalExpress are you using? You can find this by selecting from the main menu Help >> About...

Phil

[michifez]

Hi Phil,

I am trying to achieve something similar with a waveform graph in LabVIEW, but have yet to pull it off.

Context: After data is recorded on to an excel file, it is read back with the intention of using a recorded variable as the time axis. One method used is to set the time axis so that it shows the relative time, with which a multiplier could be used to enforce the desirable time axis values (indirectly).

Question: Is there a property node that can do this? The multiplier property node comes close, but it would much easier to instead have the exact values on the time axis.

Your assistance would be appreciated.

Thanks

Ifeanyi

[Phil_J1]

Hi,

You probably already figured out the solution, but have you tried using the property for Scale >> Min and Max and set those to achieve what you want. That would allow to skip the multipler. Or perhaps a combination of these properties on the Scale can accomplish this.

If this doesn't work, have you tried posting this question to the general LabVIEW forum?

Phil