Decoding CPU Diagnostic Buffer Message 'No Entry in Text Database' and Hexadecimal Event IDs in PCS 7

The message 'No Entry in text database. Hexadecimal values will be displayed' in the SIMATIC S7-400 / PCS 7 CPU diagnostic buffer indicates that the STEP 7 engineering software lacks the symbolic text library definition for a specific internal firmware or communication event. For Event ID 16#A217 with Additional Info 16#80C3, the event signifies an outgoing S7 communication resource error (Class 0xA system event), where status code 16#80C3 indicates that internal communication resources or connection buffers were exhausted. To decode unknown hexadecimal events, cross-reference the Event ID class and status words against the STEP 7 System Software Reference Manual.

Executive Summary

When diagnosing automation anomalies in SIMATIC S7-400 controllers running PCS 7 V8.2, maintenance engineers frequently encounter the diagnostic buffer entry: 'No Entry in text database. Hexadecimal values will be displayed'. This occurs when a firmware event ID, particularly from communication processors, system function blocks (SFBs), or internal operating system tasks, has no corresponding entry in the local STEP 7 text database (s7tex*.dbf). In this case, Event ID 16# A217 with DatID 16# 50 C0 and Additional Info 16# 80C3 points directly to an S7 communication block error. This guide breaks down the structure of STEP 7 diagnostic buffer records, decodes the specific hexadecimal parameters, and outlines diagnostic resolution steps.

Architectural and System Mechanics

The SIMATIC S7 CPU Diagnostic Buffer stores a ring memory of diagnostic events containing structured binary fields:

Event ID (e.g., 16# A217):
High Nibble (16#A): Indicates an event class related to communication functions, user operating states, or peripheral events.
Remaining Bytes (16#217): Identifies the specific function block or internal operating system service.
DatID (Data ID):
16#50: Identifies the data format as S7 communication / system service status.
16#C0: Indicates an outgoing event (clearing of a previous fault condition).
Additional Info 1 (16# 80C3):
Standard STEP 7 communication status code: 16#80C3 = 'Internal resources temporarily exhausted' or 'Maximum number of simultaneous communication jobs reached'.
Additional Info 3 (16# 3FE6):
The local connection ID or diagnostic reference address representing the active S7 connection.

Step-by-Step Engineering and Implementation Procedure

Step 1: Extract Diagnostic Buffer Record Details

In SIMATIC Manager, select the CPU 416-3, open 'PLC' -> 'Diagnostic/Setting' -> 'Module Information' -> 'Diagnostic Buffer'. Click 'Save As...' to export the raw buffer to a text file for complete hexadecimal analysis.

Step 2: Decode the Hexadecimal Parameters

Event ID 16# A217: Event class A represents S7 communication services (e.g., BSEND, BRCV, USEND, URCV, or NetPro configured connections).
DatID 16# 50 C0: 50 indicates communication job reporting; C0 designates an outgoing event (transition from error back to normal state).
Additional Info 16# 80C3: Corresponds to standard communication error code 80C3 (Resource bottleneck: CPU communication buffer full or partner not acknowledging packets).
Additional Info 16# 3FE6: Hexadecimal representation of internal connection reference (decimal 16358).

Step 3: Investigate S7 Communication Load in NetPro and HW Config

Open NetPro, select the CPU 416-3, and inspect the connection table.
Check the number of configured S7 connections versus the maximum communication connection limit of the CPU 416-3.
In HW Config, open CPU Object Properties -> 'Cycle/Clock Memory'. Inspect the parameter 'Scan cycle load from communication (%)' (default 20%). If OS communication is heavy, increase communication load allotment up to 30-40%.

Step 4: Update STEP 7 Hardware Updates and Text Databases

To prevent the 'No Entry in text database' warning for newer firmware events, install the latest STEP 7 Hardware Support Packages (HSP) and CPU firmware description files on the Engineering Station.

Verification

Verify diagnostic status:
1. In Module Information -> Communication tab, inspect active connections and verify that connection count is well within CPU limits.
2. Monitor the CPU diagnostic buffer during peak OS polling; confirm that new 80C3 resource exhaustion events do not reoccur.
3. Verify that WinCC runtime tags across the relevant S7 connections update smoothly without yellow communication quality flags.

Limitations and Operational Precautions

Operational precautions:
- Do not increase communication cycle load excessively (e.g., above 50%), as this reduces CPU processing time available for cyclic OB execution, potentially increasing OB1 or cyclic OB cycle times.
- An outgoing event (DatID C0) indicates that the system has recovered; do not restart the controller solely because an outgoing event was logged.
- When using third-party communication blocks or custom SCL functions, ensure communication blocks check BUSY, ERROR, and STATUS outputs before re-triggering jobs.

Engineer FAQ

Q: Why does STEP 7 say 'No Entry in text database'?

A: Because the local STEP 7 software version does not have the text string description corresponding to that specific firmware or internal system event ID.

Q: What does error code 80C3 mean in S7 communication?

A: Error 80C3 indicates that internal communication memory or connection resources are temporarily exhausted.

Q: Does Event ID 16#A217 cause the CPU to enter STOP mode?

A: No. Event A217 is an informational or communication warning event that does not trigger CPU shutdown.

Q: How can I identify which connection caused 16#3FE6?

A: Examine the connection table in NetPro or Module Information -> Communication to find the connection ID matching the hex address.

Q: Will updating CPU firmware eliminate this message?

A: Updating STEP 7 HSPs and CPU firmware text libraries provides plain-text descriptions for previously unrecognized event IDs.

Technical References

Related Tags

Diagnostic Buffer, Event ID A217, Error 80C3, S7-400, Communication Diagnostics

`Communication Diagnostics`

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Decoding CPU Diagnostic Buffer Message 'No Entry in Text Database' and Hexadecimal Event IDs in PCS 7