How can I have a waveform graph (or chart) updated using the value propertynode without loosing previous data plots?

[dpir]

I want to have a master waveform graph (or chart) capable of displaying data via the value property node. There are several value nodes in a flat sequence structure. The problem is that the graph (or chart) doest keep the previous data and does display just the very last value property node. Can anybody help me? 

[johnsold]

A graph does not "keep" any data. It is strictly an indicator which displays the most recent values written to it. 

A chart has an internal buffer, called, Chart History which retains previously written data until the buffer is full. Then it removes the oldest data when new data is sent to the chart.

1. Sequence structures are almost never needed in good LabVIEW programs. They defeat dataflow and limit parallelism.

2. Value property nodes (and local variables) should only be used under special circumstances and a sequence structure is not one of those.

A state machine with shift registers or a Producer/Consumer architecture are more likely to be better ways of doing what you are trying to do and can be implemented without sequence structures or Value property nodes.

Lynn

[dpir]

Thanks a lot!