Questions about Trend Display behavior in EasyBuilder Pro

[jmcascales]

• HMI Model: cMT3162X V2
• EasyBuilder Pro Version: 6.10.01.609

Hello everyone,

I am currently working with the Trend Display object in EasyBuilder Pro, and I would like to achieve the following features or understand if they are possible:

1) Automatic Y-axis scaling (generic)

I would like to display a Y-axis that automatically adapts to the values of the sampled variables.
However, I don’t want to bind the Y-axis to a specific variable. Instead, I am looking for a generic Y-axis that dynamically adjusts based on all displayed data.

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2) Y-axis zoom limitation vs gesture zoom

When using the Y-axis zoom tool, there is a point where it cannot zoom in further.
However, if I zoom using a two-finger gesture, I can zoom in much more.

The issue is that when I release my fingers, the extra zoom is lost and the display returns to the previous zoom level.

For my application, it is important that:

• The zoom applied with gestures remains fixed

• The user can keep that zoom level without reverting

Is there any way to make the gesture zoom persistent?

3) Long-term storage and automatic data management for Trend data

My goal is to keep the Trend data stored for as long as possible.

To achieve this, I would like to:

• Use an external USB device as the main storage location instead of (or in addition to) the internal memory

• Maximize the available storage time for historical data

• Implement some kind of automatic data management, where:

  • Old data is automatically deleted

  • New data continues to be recorded without interruption

In other words, I am looking for a solution similar to a circular buffer system, but using external storage, so that the Trend history can be kept available for the longest possible time without running out of memory.

I would like to know:

• If it is possible to store Data Sampling files directly on a USB device

• How storage limits can be configured or monitored

• Whether automatic overwrite/cleanup mechanisms can be configured

[Arden.y]

Hi @jmcascales ,

Thank you for your questions. We would be happy to clarify those for you.

To achieve an dynamic Y-axis scaling feature, we recommend using the Dynamic limit or Dynamic scale object, and then include this alongside the Trend Display.

The built-in gesture-based zoom feature on the Trend Display object does not currently provide a mechanism to lock or preserve the zoom level after the gesture is released.

If a more permanent zoom view is required, we recommend using the Dynamic limits feature in the Channel tab of the Trend Display settings. This lets you better control the channel’s min and max from LW registers, so you can control the displayed Y-axis range directly and it won’t revert back. These registers can then be updated from numeric inputs or a macro, so it will be easier to navigate the display.

In terms of long-term USB storage, it is possible to store Data Sampling files directly on USB. In the Data Sampling object Settings, under the History files section, select save to USB disk as the destination. You can also set the folder name and file organization, and the preservation limit here.

On cMT/cMT X Series, USB-mode data sampling already behaves similarly to a pipeline: records accumulate in HMI memory, and as soon as the HMI hits 10,000 records, the batch is transferred to the USB and the oldest 1,000 records on the HMI are cleared. The USB holds the long-term archive.

For additional details, please refer to Chapter 8 — Data Sampling in the EB Pro User Manual, which covers the full set of storage options and configuration settings: Link.