# Powerchart: interpolation "curveStepAfter" **URL:** \ **Category:** Ignition\ **Created:** [November 6, 2025, 4:04pm UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003 "2025-11-06T16:04:59Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![stijn.verhelst](https://avatars.discourse-cdn.com/v4/letter/s/73ab20/32.png) [@stijn.verhelst](https://forum.inductiveautomation.com/u/stijn.verhelst)\ **Post date:** [November 6, 2025, 4:04pm UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/1 "2025-11-06T16:04:59Z")
Hi everyone, We would like to use the interpolation type “curveStepAfter” for our Powerchart. To achieve a true curveStepAfter visualization, we need to set the “pointCount” parameter to -1. - D3’s curveStepAfter: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/8/a875ea3ee99418d6c966c822a15ef5312ce594e5.png) - Graph with pointCount = 300: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/f/6f1a3fcccb1ac63c5beb01474b1d817d566eca55.png) - Graph with pointCount = -1: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/6/965c02625968c3b50c13923ff914a45bdb34f840.png) However, when we set pointCount = -1, we encounter performance issues when loading data over longer time periods, since all of that data needs to be loaded into the browser at once. Is there a way to preserve the true curveStepAfter interpolation behavior while avoiding the limitations caused by loading large amounts of data? Kind regards, Stijn ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [November 6, 2025, 4:10pm UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/2 "2025-11-06T16:10:06Z")
Consider using tall output format if displaying multiple pens, and post-processing in **private** custom properties. Non-private custom properties are sent to the browser even if not used there. ---
**Author:** ![vtran](https://avatars.discourse-cdn.com/v4/letter/v/779978/32.png) [@vtran](https://forum.inductiveautomation.com/u/vtran)\ **Post date:** [November 6, 2025, 5:08pm UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/3 "2025-11-06T17:08:44Z")
What’s the date type of the tag? If you’re expecting it to be stepping, then it should be one of the integer types (Integer, Short, Long depending on the data range). Sometimes, OPC tags can still come in as Float/Double, but you can still force it to be an integer type in Ignition. Alternatively, I think you can also change the Deadband Style to Discrete under the tag’s History config ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/0/e043f30ecc68884dd4bd653c3b49a1b5fb66a6f3.png) ---
**Author:** ![stijn.verhelst](https://avatars.discourse-cdn.com/v4/letter/s/73ab20/32.png) [@stijn.verhelst](https://forum.inductiveautomation.com/u/stijn.verhelst)\ **Post date:** [November 6, 2025, 6:49pm UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/4 "2025-11-06T18:49:51Z")
> [@pturmel](#): > > Consider using tall output format if displaying multiple pens I've reviewed the Perspective Power Chart documentation but cannot find a setting to choose between tall and wide output formats. Users currently select their own pens, which populates the `pens[x].data.source` field with the historical tag path. The tall/wide output format option appears to be available only for Tag History Bindings and the [system.tag.queryTagHistory](https://www.docs.inductiveautomation.com/docs/8.1/appendix/scripting-functions/system-tag/system-tag-queryTagHistory) scripting function, not directly on the Power Chart component itself. Could you clarify where this option is available? > [@pturmel](#): > > and post-processing in **private** custom properties. Non-private custom properties are sent to the browser even if not used there. This is an interesting optimization point. Could you elaborate further? We have several custom tag properties, and understanding how to leverage private custom properties for post-processing would be interesting for reducing data transmission. > [@vtran](#): > > What’s the date type of the tag? Most of our tags are Float. We have several tags that increase approximately linearly over time, but once they reach a certain value, they remain exactly at that value for about 2 hours. After the next OPC tag read, the value resets to its minimum. Since there are no tag value changes during this plateau, no new entries are written to the historian (which is the desired behavior), but this causes improper visualization with incorrect interpolation applied (e.g. not having the `pointCount = -1` and `pens[x].display.interpolation = curveStepAfter`). I've attempted to illustrate this below: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/2/923ad57f173fc5daedda66adaf9681654a23a149.png) > [@vtran](#): > > Alternatively, I think you can also change the Deadband Style to Discrete under the tag’s History config We could experiment with this approach, although I understand it primarily affects the logic behind how values are recorded rather than how they're visualized in the Power Chart component. ---
**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\ **Post date:** [November 6, 2025, 6:53pm UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/5 "2025-11-06T18:53:05Z")
> [@vtran](#): > > Alternatively, I think you can also change the Deadband Style to Discrete under the tag’s History config This is the key. > [@Power Chart Interpolation](https://forum.inductiveautomation.com/t/power-chart-interpolation/111041/9): > > I'm pretty sure the display.Interpolation property is applied to the displayed trend data after the points are aggregated and interpolated from the historian raw data to match the required point count. These trends are both incrementing second counters. The green has an analog deadband style and the orange is discrete. Other than that they are setup the same with a deadband of 5. The display.Interpolation is set to curveStepAfter. Setting the pointCount to a high number make the charts interpo… > [@stijn.verhelst](#): > > We could experiment with this approach, although I understand it primarily affects the logic behind how values are recorded rather than how they're visualized in the Power Chart component. This was my understanding too, but this is incorrect (see post attached) ---
**Author:** ![msmith](https://avatars.discourse-cdn.com/v4/letter/m/aca169/32.png) [@msmith](https://forum.inductiveautomation.com/u/msmith)\ **Post date:** [January 23, 2026, 2:20am UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/6 "2026-01-23T02:20:24Z")
Even with the deadband style set to discrete, ignition still interpolates the data, is there a workaround to have floats not interpolate? ---
**Author:** ![vtran](https://avatars.discourse-cdn.com/v4/letter/v/779978/32.png) [@vtran](https://forum.inductiveautomation.com/u/vtran)\ **Post date:** [January 23, 2026, 3:56pm UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/7 "2026-01-23T15:56:10Z")
Is it on a Powerchart? You might need to adjust the Pen’s Interpolation settings. In your case, probably one of the CurveStep ones. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/0/80b7f2a1bb083ef8a3aafbaa9d52586c6ded4928.png) And depending on your query range, might also want to adjust your Max Time Between Samples on your tag config if you’re seeing too many gaps. ---
**Author:** ![msmith](https://avatars.discourse-cdn.com/v4/letter/m/aca169/32.png) [@msmith](https://forum.inductiveautomation.com/u/msmith)\ **Post date:** [January 26, 2026, 9:06pm UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/8 "2026-01-26T21:06:25Z")
Yes I am using CurveStepAfter on the power chart. Floats seem to always be interpolated regardless of deadband style. ---
**Author:** ![Jordan\_Brandon](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@Jordan\_Brandon](https://forum.inductiveautomation.com/u/Jordan_Brandon)\ **Post date:** [February 3, 2026, 12:20am UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/9 "2026-02-03T00:20:38Z")
I have been having the same issue for a long time. My tag Deadband Style property is set to discrete and the pen style in the chart is curveStepAfter. Any advice? This has been a major problem for all my users for a long time. We were able to fix it in Vision’s Easy Chart, but not Perspective’s Power Chart. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/4/b/4b49b85fff6e91e212d5043e4f84d74f7f0e136e.png) ---
**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\ **Post date:** [February 3, 2026, 4:25am UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/10 "2026-02-03T04:25:32Z")
Can you show the tag's history config, just for fun? ---
**Author:** ![Jordan\_Brandon](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@Jordan\_Brandon](https://forum.inductiveautomation.com/u/Jordan_Brandon)\ **Post date:** [February 3, 2026, 6:37pm UTC](https://forum.inductiveautomation.com/t/powerchart-interpolation-curvestepafter/112003/11 "2026-02-03T18:37:55Z")
@nminchin ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/8/f8773f754bb4e61fc28bf1a353e2488df95e8e35.png)