What the screen is telling you is simple: the chart can display configured data, but its initial scale remains 0 to 100. The Extra Scheme Components Plugin does not provide a component-property setting for replacing that default range. An operator must change the scale manually on the running scheme.
What should appear before you change the scale?
First establish that the chart component itself is present and active. Add the chart to the scheme and complete its component properties. Those properties control whether the chart is displayed and which configured data it presents; they do not define a different default scale.
| Setting or condition | Location | Effect |
|---|---|---|
| Chart component | Scheme configuration | Places the chart on the operator screen |
| Component properties | Chart configuration | Defines the component and its data presentation |
| Scale endpoints | Running chart, changed by the user | Changes the visible range from the default 0 to 100
|
Do not search the component properties for an alternate default-range field. Configure the display first, then handle scaling from the operator screen.
Check: Open the scheme and confirm that the chart frame, axes, or plotting area appears before tracing any data problem.
Is the chart connected to the intended tag?
A visible chart can still be empty or misleading when its data binding points to the wrong tag. Trace the signal from the chart back through the configured tag, communication driver, and controller value. The tag may contain the correct process value while the chart references another data source; in that case, the tag is right and the binding is wrong.
- Identify the process variable that the chart is meant to display.
- Read that variable in the SCADA tag view or equivalent live-data display.
- Compare the live tag with the data source selected in the chart component properties.
- Confirm that the communication driver is updating the tag rather than leaving a cached or stale value.
- Compare the SCADA value with the controller value using the controller engineering tool or another established diagnostic view.
When the controller and SCADA tag agree but the plot does not, correct the chart binding. When the tag and controller disagree, work backward through the driver configuration, address mapping, data type, and communication status before changing the chart.
Check: Change the process value under controlled conditions and verify that the chart receives the same change as the bound tag.
Why can a working chart still look wrong?
The default range can hide valid data. A value much smaller than 100 may appear almost flat near the bottom of the plot. A value above the visible maximum may be clipped or remain outside the displayed area. Neither symptom proves that the tag or driver has failed.
| Operator symptom | Check | Likely decision |
|---|---|---|
| Chart is present but no trend is visible | Read the live tag and confirm that it changes | Repair the binding or upstream data path if the chart does not follow |
| Trend looks nearly flat | Compare the tag's normal operating band with 0 to 100
|
Manually narrow the visible range |
| Trace reaches the top or leaves the plot | Compare the live value with the current upper endpoint | Manually raise the upper endpoint |
| Displayed value disagrees with the controller | Inspect driver status, mapping, and data type | Correct the data path before scaling |
Scaling changes how values are presented; it does not repair a wrong address, failed driver, stale tag, or incorrect data type.
Check: Confirm that the live value falls within the current chart range and that its plotted position is reasonable for that range.
How does the operator change the chart range?
Use the scale controls available to the user on the running chart. The exact control placement depends on the installed plugin interface, so identify the chart's manual scale or range control rather than looking for an unsupported design-time property.
- Open the scheme containing the configured chart.
- Select or activate the chart so its user controls are available.
- Open the manual scale or range adjustment.
- Enter or select lower and upper endpoints that bracket the actual operating values.
- Apply the change and inspect the trace against the revised axis.
Choose endpoints from the process operating band and alarm context, not merely from the instantaneous reading. A range that is too wide hides useful movement; a range that is too narrow clips normal excursions. If operators require a standard viewing range, document the endpoints in the operating procedure because the plugin requires the user to make the change manually.
Check: Verify that the axis shows the selected endpoints and that the current tag value appears at the expected relative position.
What mistakes recur during commissioning?
The most common mistake is treating a display-scale problem as a controller or driver fault. Read the numeric tag before editing communications. Another is changing the scale while the chart is bound to the wrong signal; a plausible trace can then conceal the binding error.
Commission the layers in a fixed order:
- Confirm the controller value.
- Confirm that the driver delivers the same value.
- Confirm that the SCADA tag updates.
- Confirm that the chart references that tag.
- Change the visible scale manually.
Also test what happens when the scheme is reopened or the client session is restarted. The known configuration rule is that the scale can be changed only manually by a user. Record the observed reload behavior for the installed system instead of relying on an alternate default-range property.
Check: Repeat the layer-by-layer comparison after reopening the display and note whether another manual scale adjustment is required.
How do you verify the complete signal path?
Run one controlled end-to-end test after configuring the component and selecting the operating range. Use a safe process change, simulated input, or approved controller test value appropriate to the installation.
- Record the starting controller value.
- Confirm the same starting value at the driver and SCADA tag.
- Confirm that the chart plots that value within the selected scale.
- Change the source value by a visible amount.
- Verify that the controller, driver, tag, and chart move in the same direction and by the same engineering-value change.
- Confirm that neither endpoint clips the expected operating band.
If every layer agrees but the trend remains visually compressed, adjust only the manual scale. If any layer disagrees, stop at the first mismatch and correct that connection before repeating the test.
Check: Complete the test only when the controller value, live tag, plotted trace, and selected axis range all agree.
FAQ
Why does the Rapid SCADA chart stay at 0 to 100?
The chart uses the default 0 to 100 range. The Extra Scheme Components Plugin permits the user to change that scale manually, not through a different default-range component property.
Why does the chart appear but show no useful trend?
Read the live tag first. If the tag changes, check the chart binding and range; if the tag does not change, trace the driver, address mapping, data type, and controller value.
Why does a correct Rapid SCADA tag plot the wrong data?
The chart may reference a different data source. Compare the tag selected in the component properties with the live tag that matches the controller.
How do I verify a manual chart-scale change?
Confirm the new axis endpoints, make a controlled source-value change, and verify that the controller, driver, SCADA tag, and plotted trace show the same engineering-value movement within the selected range.