C135 PCS 7 (PCS7)
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Resolving 'SFC Chart Does Not Exist (Any Longer) Note (1739:20)' During Download Identification in PCS 7 v8.2

Resolving 'SFC Chart Does Not Exist (Any Longer) Note (1739:20)' During Download Identification in PCS 7 v8.2

In SIMATIC PCS 7 v8.2, encountering the error dialog 'SFC chart does not exist (any longer). Note (1739:20)' during the AS download identification phase (stalling before the download dialog appears) indicates that the internal online/offline comparison cache within the S7 program database (specifically the ES_MAP or ba_cat tables) references a deleted or modified SFC chart whose block instance is missing from the compiled program. Even after performing block database cleanup, consistency checks, and slow project reorganization, the download analyzer fails when matching online controller blocks against the offline database. To permanently resolve this defect, engineers must install the official Siemens hotfix patch 'SIMATIC CFC V8.2 Update 3', clear the offline comparison cache, and recompile the S7 program.

Table of Contents

Mechanism of the Download Identification Phase in PCS 7

When an engineer initiates an automation download in SIMATIC Manager or CFC (PLC > Download...), the engineering software does not immediately transmit blocks to the controller.

First, it executes the Download Identification Phase:
1. The engineering system reads the block directory from the online CPU work memory.
2. It compares online block numbers, checksums, and timestamps against the offline S7 Program database and the ES_MAP (Engineering Station Mapping) catalog.
3. It identifies which blocks were added, deleted, or modified to construct the Download Changes delta package.

If the download analyzer encounters an entry in ES_MAP referencing an SFC chart ID that was deleted or restructured, but whose internal pointer was not cleared, the identification routine crashes with:
SFC chart does not exist (any longer). Note (1739:20).

Root Causes of Note 1739:20 During Download Identification

This specific failure in PCS 7 v8.2 originates from three interrelated issues:

  1. Systemic CFC Compiler Bug in PCS 7 v8.2 (Base to Upd2): The CFC/SFC compiler in unpatched v8.2 failed to delete internal tracking records in the project's chart management table when SFC Types or instances were removed. Siemens officially acknowledged this defect and issued CFC V8.2 Update 3.
  2. Orphaned ES_MAP Block References: ES_MAP is an internal binary file tracking the mapping between CFC charts and compiled Function Blocks (FBs/DBs). If an SFC was deleted offline while the compiled FB remained online in the CPU, the comparison algorithm crashes.
  3. Incomplete SFC Type Modification: Modifying an SFC Type interface (adding/removing steps) while instances were still loaded online creates an unresolvable structural discrepancy.

Why Standard Database Reorganization Fails to Clear the Error

Engineers often attempt:
- Deleting ES_MAP instances manually.
- Running Save As with Reorganization (Slow).
- Deleting all charts except one simple chart.

However, the error persists because:
- Slow reorganization compacts database sectors but does not alter table relationship schemas defined by the flawed compiler.
- As long as the unpatched CFC v8.2 binary (cfc.exe / sfc.exe) executes the download identification routine, it continues to misinterpret historical comparison records.

The Official Siemens Patch: CFC V8.2 Update 3

Siemens resolved Note 1739:20 definitively with SIMATIC CFC V8.2 Update 3:
- Entry ID: 109743846.
- Functionality: Replaces the faulty download analyzer module.
- Automated Cache Scrubbing: During the download identification phase, the patched analyzer automatically purges obsolete SFC chart references from the comparison cache, allowing the download dialog to open smoothly.

Step-by-Step Procedure: Purging Cache and Recovering Download

Follow this procedure to eliminate the error:

Step 1: Install SIMATIC CFC V8.2 Update 3

  1. Close SIMATIC Manager and all engineering tools.
  2. Download and install CFC V8.2 Update 3 (or the latest cumulative update) from SIOS.
  3. Restart the Engineering Station.

Step 2: Clear Offline Compilation Cache

  1. Open SIMATIC Manager and open the affected project.
  2. In the component view, navigate to [AS Station] > [CPU Object] > S7 Program.
  3. Select the Charts folder.
  4. Select menu Options > Charts > Check Consistency. Allow the tool to repair any identified broken pointers.

Step 3: Execute Full Compilation

  1. Right-click the Charts folder and select Compile > Charts as Program.
  2. Select Entire program (do not select Changes only).
  3. Check the box Generate SCL source (if available) to force clean block re-generation.
  4. Ensure compilation completes with 0 errors.

Step 4: Execute AS Download

  1. Select PLC > Download....
  2. The download identification phase will now execute cleanly without Note 1739:20.
  3. Select Download Changes (or Entire program if the plant is in a planned shutdown) and proceed.

Diagnostic Matrix for AS Download Aborts

The table below outlines common download identification errors:

Note / Error CodeError DescriptionRoot CauseRemediation ActionNote 1739:20SFC chart does not exist (any longer)Orphaned SFC reference in comparison cacheInstall CFC V8.2 Upd3; full compileNote 1739:15SFC Type cannot be modifiedActive instances exist onlineUpdate block types across all chartsNote 1739:35Insufficient memory in CPUWork memory fragmentedPerform memory compression in Module InfoError 4540Download rejected by CPUBlock number exceeds CPU limitReconfigure reserved FB ranges in CFC

Verification

To confirm that the download pipeline is restored:
1. Download Identification Execution: In CFC Editor, click PLC > Download; verify that the download dialog opens within 5 seconds without triggering Note 1739:20.
2. Delta Download Test: Execute Download Changes in RUN mode; verify that all modified blocks transfer to the S7-400 CPU without stopping the controller.
3. Online Monitoring Check: Switch CFC to online test mode; verify that all SFC charts display live step states with solid green halos.

Limitations and Operational Precautions

Engineering teams must observe the following precautions:
- Never manually delete system files inside the S7 project directory (*.dbf, *.db) in Windows Explorer; database manipulations must strictly use SIMATIC Manager tools.
- If performing a full download (Entire program), the S7-400 CPU will transition into STOP mode; schedule full downloads strictly during plant cold shutdowns.
- Ensure all engineering workstations participating in multi-user engineering have CFC V8.2 Update 3 installed to prevent re-corrupting the project database.

Engineer FAQ

Will installing CFC V8.2 Update 3 force a full CPU download?

No. Installing CFC Update 3 repairs the engineering compiler and download analyzer on the ES; it does not force an entire CPU download or require a controller STOP.

What should I do if the error persists even after installing Update 3?

If the database was severely damaged prior to updating, create a new S7 Program folder in the project, copy the valid CFC charts into it, compile the new program, and download.

Where can I find the official Siemens announcement for Note 1739:20?

Siemens published the fix details in the release notes of SIMATIC CFC V8.2 Update 3 under SIOS Entry ID 109743846.

Technical References

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Related Tags

  • SFC Error 1739:20
  • CFC Update 3
  • Download Identification
  • ES_MAP
  • PCS 7 V8.2
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