Disabling S7-1200 PROFINET IO Device Failure Errors in TIA V17

Problem Overview

When consolidating multiple SIMATIC S7-1200 stations (e.g., a fleet of CPU 1214C DC/DC/DC controllers spread across geographically distributed wind turbine sites) into a single TIA Portal project, every PROFINET IO device configured in the device configuration must be reachable at runtime. If an IO device listed in the project is physically absent on the network, the CPU logs an "IO device failure – IO device not found" diagnostic entry and the SF (Group Fault) LED illuminates. The fault propagates to OB82, OB83, OB86, and the diagnostic buffer, generating noise that masks real process faults and trips the maintenance crew into nuisance callouts.

This article documents three field-proven methods to suppress or mask expected PROFINET IO device failures on the S7-1200 (firmware V4.2 through V4.6) inside TIA Portal V17 while still preserving the ability to detect truly missing critical devices.

Prerequisites

• SIMATIC S7-1200 CPU 1214C DC/DC/DC (order number 6ES7214-1AG40-0XB0) with firmware V4.2 or higher. TIA Portal V17 minimum CPU firmware is V4.2; V4.4 is required for full symbolic diagnostic access.
• TIA Portal V17 Update 4 or later (Build 17.0.0.170). The LCC (Library of Communication and Configuration) requires the matching V17 distribution; older V16 libraries can be upgraded but the internal block versions are not always available.
• The configured PROFINET IO devices must be standard PROFINET devices (not shared devices, not MRP clients on ring ports that the S7-1200 CPU is supposed to manage).
• Programming knowledge of SCL or LAD/FBD, and a basic understanding of the PNIO stack diagnostics.

Understanding S7-1200 CPU Error Behavior

The S7-1200 system manual defines a layered fault response. When the PROFINET controller detects a station failure (lost AR - Application Relationship), the following sequence occurs:

1. The PNIO stack raises a station-level diagnostic interrupt.
2. The operating system calls OB86 (Rack/Station failure). If OB86 is not loaded, the CPU transitions to STOP. If OB86 is present but empty, the CPU remains in RUN but logs the diagnostic buffer entry.
3. The diagnostic buffer records event ID 0x013C ("IO device failure") or 0x013E ("IO device returned") with the station number and PROFINET device name.
4. The SF LED is latched until the diagnostic buffer is read or the station returns.

Reference: SIMATIC S7-1200 Manual Collection – CPU Error Behavior.

The fatal error path is separate: when the firmware detects a non-recoverable internal fault (e.g., firmware defect, watchdog overflow), the CPU attempts a defect-mode restart. After a successful restart, the diagnostic buffer records a power-on event; after a failed restart, the CPU remains in STOP with the SF LED steady on. This behavior cannot be masked with user logic; it is a hardware/firmware level escalation.

Method 1: D_ACT_DP – Native Enable/Disable Function

The D_ACT_DP function is part of the standard IEC 61131-3 distributed I/O library and is documented in the Siemens support entry "How do you enable and disable DP slave and PROFINET IO device?". The block signature is:

The ADDR parameter must point to the diagnostic address of the IO device. In TIA Portal V17, locate it in Devices & Networks → [IO Device] → Properties → PROFINET interface → [Port / Diagnostics tab. The diagnostic address is the slot-0 submodule address assigned automatically by the PROFINET controller, and it is the only valid input for D_ACT_DP on a PROFINET IO device (on PROFIBUS DP, use the slave's diagnostic address).

Error Code Reference for D_ACT_DP

SCL Example Call

// Deactivate station 4 (diagnostic address 256) on cold start
IF "FirstScan" THEN
    "dbDisableStations".REQ  := TRUE;
    "dbDisableStations".MODE := 2;       // 2 = deactivate
    "dbDisableStations".ADDR := 256;     // diagnostic address of IO device 4
    D_ACT_DP(
        REQ     := "dbDisableStations".REQ,
        MODE    := "dbDisableStations".MODE,
        ADDR    := "dbDisableStations".ADDR,
        RET_VAL := "dbDisableStations".RetVal,
        BUSY    := "dbDisableStations".Busy);
END_IF;

Method 2: LCC ReconfigSys and ReconfigIOSystem

The Siemens LCC (Library Communication & Configuration) provides finer-grained reconfiguration. The V17 distribution is shipped as LCC_V17.zip and contains the FB ReconfigIOSystem, the FB ReconfigIODevice, and supporting types. The V16 library does not always port cleanly to V17 because the PNIO_IFC type definitions were refactored between V16 and V17 (the V16 → V17 upgrade preserves the blocks but flags the PNIO_IFC_v2 as obsolete).

ReconfigIOSystem Interface

ReconfigIOSystem Status Word Bits

Call Sequence

1. Open TIA Portal V17 → Options → Manage Libraries → import LCC_V17.zip.
2. Drag ReconfigIOSystem into the project. TIA may require you to update the type version to V17.0.1; accept.
3. Wire hwInterface to the CPU PROFINET interface symbol (e.g., "Local~PROFINET_interface_1").
4. Call from OB100 with mode := 0 and populate deviceList with the PROFINET station names of the wind turbines not present at this site.
5. Evaluate status bit 1 (Done) before allowing OB1 to read any IO from those devices.

If the ReconfigIOSystem block is not visible in the V17 master copy library, verify that the Hardware Support Package for the CPU 1214C is installed at firmware V4.4 or higher: Options → Support Packages → Installed. The block depends on the PNIO system constants generated by the compiler; without the matching support package, the type references resolve to V15.1 stubs that do not export the reconfiguration entry points.

Method 3: Configuration-Time Suppression (No Code Change)

If runtime reconfiguration is not required (e.g., the per-site device list is static and known at engineering time), the cleanest approach is to not configure the absent devices in the TIA project at all, and use a centralized project where each site has a derived sub-device set via a project library master copy. This avoids the firmware-level diagnostic entirely.

For a single shared project across sites, use TIA Portal's "Station Configuration Editor" feature (V17 Update 4+): Project tree → CPU → Properties → PROFINET interface → Operating mode → "IO device substitution permitted". With this option enabled, the PNIO stack tolerates the listed devices being absent for the configured Watchdog time (default 3 s) and does not raise OB86 during that grace period. Beyond the watchdog, the failure propagates normally.

Diagnostic Event ID Reference (S7-1200 PROFINET)

Verification Procedure

1. Compile the project (Project → Compile → Software (rebuild all)) and download to the CPU 1214C. Ensure the CPU is in STOP during download.
2. Power-cycle the CPU; observe OB100 executes and the D_ACT_DP or ReconfigIOSystem call completes with RET_VAL = 0 / status bit 1 set.
3. Connect TIA Portal online → Online & Diagnostics → Diagnostics buffer. Confirm that no event 0x013C entry is present for the deactivated stations.
4. Verify the SF LED is OFF after the boot sequence completes (allow up to 10 s for the PROFINET stack to settle).
5. Reconnect one of the deactivated devices; verify that an event 0x013E ("IO device returned") is logged. If expected, call D_ACT_DP with MODE := 1 from OB1 on a rising edge of the return event to formally reactivate.
6. Force a real fault by disconnecting a critical device (one that should still alarm). Confirm OB86 fires, the diagnostic buffer logs the failure, and the SF LED activates. This validates that suppression is targeted and not blanket.

Troubleshooting Matrix

Edge Cases and Field Notes

• Device name vs. IP address. PROFINET devices are identified by their station name, not IP. If two sites use the same device name (e.g., "et200sp-turbine-1"), the CPU at site B will see site A's device when networked together. Always encode the site in the device name (e.g., "et200sp-FR-S01-T01").
• OB86 priority. If OB86 is loaded with priority higher than OB1, it preempts and may race with D_ACT_DP in OB100. Configure OB86 with priority 7 and OB100 with priority 27 to ensure restart completes first.
• Firmware V4.5 behavior change. From firmware V4.5 onward, the diagnostic buffer no longer records a 0x013C event for devices deactivated via D_ACT_DP in OB100. Older V4.2/4.3 firmware still records the entry even on successful deactivation. Check the CPU's Online & Diagnostics → Diagnostics tab to confirm the firmware version.
• PROFINET vs. PROFIBUS mix. D_ACT_DP works on both, but the ADDR interpretation differs. On PROFINET, use the diagnostic address of the IO device's slot 0. On PROFIBUS, use the slave's diagnostic address (slot 0 of the slave).

Related Official Documentation

For deeper reference on the methods described here:

• Siemens Support Entry 105020938 – Enable/Disable DP slave and PROFINET IO device
• Siemens Support Entry 29430270 – Which options are available in the TIA Portal to deactivate an IO device?
• SIMATIC S7-1200 Manual Collection – CPU Error Behavior