I have a client who is reporting that Easy Charts in their HMI are updating 30 to 45 sec after they see other discrete indications on the screen have updated. Is there a way to optimize this performance, or is this just the nature of a historian-based chart? Are there any other ways to chart real-time data in Vision?
Thank you!
How positive are you that this client's local time is actually correct? That's the most common cause of easy chart "lag" in my experience. If the local machine thinks "right now" is 45 seconds in the past, then your 'realtime' easy chart is always going to be wrong.
Thank you for the input. I will definitely check that.
There is a point in the process where the operator is watching the chart for a change to determine a set point for a subsequent step, so I do believe they are seeing a lag between discrete indications and a chart on the same screen, but I cannot confirm that this lag actually adds up to 30+ seconds.
Actually just checked and that machine is within one or two seconds of time.gov.
Paul's suggestion was spot on for me
For future reference, the lag is created by the relative difference between the gateway and the client computer times.
I threw a label on a vision window and bound the text as:
secondsBetween({[System]Client/System/CurrentDateTime},{[System]Gateway/CurrentDateTime})
A similar type of timestamp issue occurs when using OPC connections to PLCs and the PLC time is wrong. This affects both Vision and Perspective.