Is realtime XY plot with history (chart XY) possible in SignalExpress ? If not, what options do I have ?
Yes it is possible, have a look at this Knowledge Base:
ok, but this seems to work only for graph type display. Doing the same thing with waveform chart display to keep history is not working. My way around was to create a mean scalar values from the recorded data and plot these in a scalar XY Graph. The strange think was that I had to add a time chart of these values for the scalar XY graph to update. Missing something here ?
Depending on your version of SignalExpress it is possible to enable history for charts as well: http://digital.ni.com/public.nsf/allkb/62729f5063c1c5e68625727c0067b815?OpenDocument
Agree that according to the documentation it should be possible, but for some strange reaseon it did not work for me. I have SE 2013 and used a simple DAQmx acquisition with cdaq 9188 and NI9234.
I've always added an Amplitudes and Levels step to pass my signals through. You can then drag those A&L signals (DBL) to a chart and view as XY graph. You can adjust the history length on the graph in Options> Data View> Chart History Length.
Keep in mind however, your sample rate will change when acquiring/viewing data from DBL signals from the Amplitudes & Levels step. So if you need more resolution you'll need to increase your sample rate.
I have used Scalar XY graph following your suggestions, although I increased the sampling rate of the channel, the graph cannot update itself realtime. The number of data points as well as chart update frequency is very low.. What do you suggest to overcome this issue?