Configuring APL Block Icons to Open Trend Views Directly in Archive Mode

To configure a SIMATIC PCS 7 Advanced Process Library (APL) block icon so that clicking the trend button on its faceplate immediately opens historical archive tags instead of online real-time curves, append the parameter ';1' to the 'trendpicturename' property on the block icon in Graphics Designer (e.g. '@pg_apl_trend.pdl;1'). The standard string '@pg_apl_trend.pdl' commands the faceplate to open in cyclic online buffer mode. Appending ';1' instructs the APL trend script to immediately configure the WinCC TrendControl in archive mode, binding directly to Tag Logging process value archives, provided archive logging is configured for the monitored variable.

Architecture of APL Trend Views: Online Buffer vs Archive Mode

In SIMATIC PCS 7 APL technological blocks (such as MonAnL, PIDConL, MotSpdCL), the standard faceplate includes a trend view button that opens @pg_apl_trend.pdl. This picture embeds a WinCC TrendControl.

By default, the trend view initializes in Online Mode:

It displays data cyclically starting from the exact second the faceplate was opened.
Historical data recorded prior to opening the faceplate is blank until the operator manually navigates toolbar options to switch to archive mode.
For process troubleshooting, operators require immediate historical context (e.g. the preceding 30 minutes or 2 hours) the instant the faceplate trend opens.

The ';1' Property Suffix Syntax and Script Mechanics

Siemens introduced an undocumented configuration flag in APL V8.0 SP2 and higher:

The APL script APL_TrendOpen evaluates the string parameter assigned to the block icon property trendpicturename.
Default parameter: @pg_apl_trend.pdl -> Evaluates parameter as 0 (Online mode).
Parameter with suffix: @pg_apl_trend.pdl;1 -> Evaluates parameter as 1 (Archive mode).
When the suffix ;1 is detected, the trend script automatically executes an internal method call switching the TrendControl provider from the online tag engine to the WinCC Process Value Archive (TagLoggingFast or TagLoggingSlow).

Step-by-Step Configuration on APL Block Icons

Follow this procedure in WinCC Graphics Designer to apply the setting:

Open Template or Process Graphic:
- To apply globally: Open @TemplateAPL.pdl (or @TemplateAPLV8.pdl) on the Engineering Station.
- To apply to a specific graphic: Open the target process graphic (e.g. Reactor01.pdl).
Select Block Icon:
- Click the block icon (e.g. @MonAnL/1 or @PIDConL/1).
Locate Property trendpicturename:
- Open Object Properties, expand Configurations (or System).
- Locate property trendpicturename.
Modify Property Value:
- Change the text from @pg_apl_trend.pdl to @pg_apl_trend.pdl;1.
Save and Propagate: Save the picture. If modifying @TemplateAPL.pdl, run Plant Hierarchy > Create/Update Block Icons to propagate the change across all plant process graphics.

WinCC Tag Logging Prerequisites for Archive Trend Display

For archive trends to display valid curves upon faceplate opening, the technological tag must be archived:

In the AS CFC chart, the block output (e.g. PV_Out.Value) must have attribute S7_archive = true (or configured via Process Object View under the Archive tab).
Execute an OS Compilation with Tags and messages selected.
In WinCC Explorer, verify that the archive tag exists inside Tag Logging under Process Value Archives.

Comparison of APL Trend Display Operating Modes

The table below contrasts trend visualization behaviors based on configuration string:

Trend Property SyntaxInitial Display ModeHistorical Data on OpenCPU / Disk OverheadTag Logging Requirement@pg_apl_trend.pdlOnline Cyclic BufferNone (Starts recording on open)LowestNot required (Uses live RAM tags)@pg_apl_trend.pdl;1Historical ArchiveImmediate (Past 30 min / 1 h)Low (SQL Archive query on open)Mandatory (Must exist in Tag Logging)Custom Trend PDLUser DefinedDefined by custom scriptVariableDepends on custom control design

Verification

Verify archive trend initialization in WinCC OS Runtime:

Open WinCC OS Runtime and navigate to a process graphic containing the modified block icon.
Click the block icon to open the technological faceplate (e.g. MonAnL).
Click the Trend View button (curve icon) on the faceplate view selector.
Confirm that the trend window opens with historical curves pre-populated from past minutes without requiring operator toolbar clicks.
Verify that the time axis displays past timestamps and the curve ruler displays accurate past process values.

Limitations and Operational Precautions

Review the following operational precautions regarding trend configurations:

Unarchived Tags Show Blank: If @pg_apl_trend.pdl;1 is configured on a block whose process variable is NOT configured in Tag Logging, the trend window will open completely blank.
Template Overwrites: If modifying standard @TemplateAPL.pdl, create a project-specific template (e.g. @TemplateAPL_Custom.pdl) to prevent the OS Project Editor from overwriting your custom property settings during updates.
SQL Query Load: Opening dozens of archive trends simultaneously on low-bandwidth terminal networks can increase SQL server query traffic; optimize archive acquisition cycles accordingly.

Engineer FAQ

What happens if I set trendpicturename to @pg_apl_trend.pdl;1 for a tag that is not archived?

The trend view will open in archive mode, but because no historical records exist in the WinCC SQL database for that tag, the curve area will display completely empty with no lines.

Can I configure the default time range (e.g. past 2 hours) for the opened trend view?

Yes, within the properties of the embedded WinCC TrendControl in @pg_apl_trend.pdl or via the APL faceplate settings block, the default time range for the time axis can be configured.

Does this ';1' parameter work in PCS 7 V7.1?

No. The automatic archive mode evaluation was officially introduced in APL V8.0 SP2. Earlier library versions require manual operator toggling via toolbar buttons.