# Online chart HDA - visualize values in web browser

**URL:** <https://community.br-automation.com/t/online-chart-hda-visualize-values-in-web-browser/12886>\
**Category:** HMI & Visualization\
**Tags:** mapp-view\
**Created:** [October 5, 2026, 10:41pm UTC](https://community.br-automation.com/t/online-chart-hda-visualize-values-in-web-browser/12886 "2026-10-05T22:41:19Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Giovanni\_Boschello](https://avatars.discourse-cdn.com/v4/letter/g/FF8800/32.png) [@Giovanni\_Boschello](https://community.br-automation.com/u/Giovanni_Boschello)\
**Post date:** [October 5, 2026, 10:41pm UTC](https://community.br-automation.com/t/online-chart-hda-visualize-values-in-web-browser/12886/1 "2026-10-05T22:41:19Z")

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Hello,

I am using online chart HDA chart but I am not able to see values in the chart.

I see time values that goes on, Y values I see the scale that adapted itself but I would expect to see Y values that goes on on the chart (and I don’t see them).  
I have values samped by opcua timer 7 (1000 ms) and I the task class of variables is every 1000 ms.

Any suggestion?  
I suspect it is a matter of timing but I don’t know.

Thanks

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**Author:** ![tommi.piiparinen](https://dub1.discourse-cdn.com/brcommunity/user_avatar/community.br-automation.com/tommi.piiparinen/32/2183_2.png) [@tommi.piiparinen](https://community.br-automation.com/u/tommi.piiparinen)\
**Post date:** [October 6, 2026, 5:12am UTC](https://community.br-automation.com/t/online-chart-hda-visualize-values-in-web-browser/12886/2 "2026-10-06T05:12:25Z")

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OnlineChart HDA uses OPC UA Historical Data Access to retrieve the values so you need to have that configured on the PLC.

Automation Help: [OPC UA C/S historical data configuration](https://help.br-automation.com/#/en/6/communication/opcua/configuration/historizing/opcuacs_uahdcfg.html)

You can also check with UA Expert by adding a new History Trend View (Document → Add → Historical Trend View) and drag the variables to the configuration part to see if the data historization is working.

Here it is also important that the client and server have their times set correctly, might be that the OnlineChart HDA is requesting data for a wrong time frame if the clocks differ.

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**Author:** ![roshini.kurian](https://dub1.discourse-cdn.com/brcommunity/user_avatar/community.br-automation.com/roshini.kurian/32/11770_2.png) [@roshini.kurian](https://community.br-automation.com/u/roshini.kurian)\
**Post date:** [October 6, 2026, 1:40pm UTC](https://community.br-automation.com/t/online-chart-hda-visualize-values-in-web-browser/12886/3 "2026-10-06T13:40:04Z")

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Hi Giovanni,

Based on the behavior described, it looks like the chart is receiving the time axis updates but not displaying any Y-axis data. This is typically caused by either historizing not being active on the variable, as Tommi mentioned previously or a graph binding/configuration issue,

A few key items to verify:

- Confirm historizing is enabled (`Enable = true`) for the exact variable used by the chart in **OpcUaMap.uad** , along with a valid buffer size and sampling interval.
- Verify the graph’s `yAxisReference` matches the name of a configured Y-axis.
- Check that the graph’s `value` binding points to the same variable that has historizing enabled and that the value is updating online.
- Also verify the Y-axis min/max limits and `timeSpan` settings are appropriate for the actual data range.

Could you confirm whether historizing is enabled for the variable in **OpcUaMap.uad** and what the current `yAxisReference` is set to for the graph?

Best,

Rosh