LPNDR Library: Reading PROFINET Data Records in TIA Portal

Overview

The LPNDR (Library for PROFINET Data Records) block library is a Siemens-supplied collection of SCL/FB function blocks for the SIMATIC S7-1200/S7-1500 controllers that read PROFINET diagnostics and configuration data records directly from PN devices. The library is published by Siemens as support entry 109753067 and is the recommended user-program method for reading record sets such as GlobalInfo, PortStatistics, NeighborInfo, and LLDP-MIB from PROFINET switches (e.g. SCALANCE XC208, XC216, XR-500) and I/O stations that are already accessible from the controller's PROFINET interface.

For TIA Portal users who need to identify what is plugged into a SCALANCE XC208 — port status, station names, MAC addresses — the LPNDR library is the right starting point. It does not, however, expose the IP addresses of the connected nodes. That limitation is critical for any commissioning engineer who plans to use LPNDR as a topology-discovery tool alongside or as a substitute for SINEC PNI.

Where to Obtain the LPNDR Library

1. Open the Siemens Industry Online Support entry 109753067 – Library for PROFINET data records.
2. Download the ZIP archive that contains the global library (.zal16 / .al16) and the example project.
3. Extract to a working directory. Do not open the library directly from the ZIP — TIA Portal cannot edit or read libraries in compressed form.
4. In TIA Portal, choose Options → Global libraries → Open library and browse to the extracted .al16 file.
5. Drag the LPNDR master copies from the library's Types folder into your project's Program blocks.

Function Block Inventory

The library exposes a family of FBs whose names follow the pattern LPNDR_<RecordName>. Each block wraps a single PROFINET Read Record (RPC Read Record) service call against the configured device.

Each block contains the same call pattern: it issues a RDREC (read data record) instruction to the configured PROFINET device on the configured AR (application relationship) and unpacks the returned raw byte stream into a typed UDT instance for direct access in the user program.

LPNDR_ReadGlobalInfo Interface

The most commonly requested block — and the one referenced in the field report — is LPNDR_ReadGlobalInfo. Its standard instance DB exposes the following inputs and outputs (confirm with the version of the library downloaded for your TIA Portal release):

The GlobalInfo UDT contains arrays for vendor/device ID, station names (as WSTRING), MAC addresses (as ARRAY[1..6] OF BYTE), and port descriptors. The exact element count depends on the connected switch's port density — for a SCALANCE XC208 the array is sized for up to 8 ports.

STATUS Word Decoding

When ERROR is asserted, decode STATUS as follows (PROFINET Read Record negative response per the standard):

IP Address Limitation

This is a real limitation when the operator console needs to map "which IP is on which port" for quick fault classification. Two practical workarounds are documented in the field report:

1. Use SINEC PNI (Primary Network Initialization) to recursively walk the network from the engineering PC. PNI queries each reachable device for its IP suite via SNMP/PN DCP and therefore can populate the IP address column. PNI is not executable from a SIMATIC PLC — it runs on a Windows host and is suitable for commissioning and diagnostics, not for continuous runtime use from the controller.
2. If the IP mapping must be available to the PLC, derive it indirectly: maintain a project-side table that maps station name → IP (entered at commissioning) and look up the IP by joining against the GlobalInfo station name array.

SCALANCE XC208 Integration

To use the LPNDR library with a SCALANCE XC208 the switch must be present in the same PROFINET IO system as the S7-1500/1200 CPU that hosts the FB. The setup steps are:

1. In the TIA Portal device view, add the SCALANCE XC208 to the PROFINET subnet of the CPU. Assign a device name and check the IO controller assignment.
2. Confirm the switch is online and reachable — the IO LED on the XC208 should be solid green and the controller should report "No fault" on the device.
3. Drag LPNDR_ReadGlobalInfo into the program and create an instance DB.
4. Wire LADDR to the Hardware identifier of the XC208 (visible in Properties → System constants or in the device's IO tag view).
5. Call the FB in a cyclic OB, for example OB1 or OB35, and trigger REQ from a clock generator (1 s is typical for monitoring; use 5–10 s for log-only use cases).

Calling Pattern in SCL

// Trigger read every second
IF "clk_1Hz" THEN
    "db_ReadGlobalInfo"(REQ := TRUE,
                         LADDR := "Local~PROFINET_interface_1".SCALANCE_XC208.HW_ID);
END_IF;

// Edge-detect completion
IF "db_ReadGlobalInfo".DONE THEN
    // Copy out for logging / HMI
    "tagStationName" := "db_ReadGlobalInfo".GlobalInfo.StationName[1];
    "tagMacAddress"  := "db_ReadGlobalInfo".GlobalInfo.MacAddress[1];
END_IF;

IF "db_ReadGlobalInfo".ERROR THEN
    "tagLastStatus" := "db_ReadGlobalInfo".STATUS;
END_IF;

Avoid calling the FB faster than the controller can complete the record read. On an S7-1516 with a single XC208 the round-trip is typically 30–80 ms; on a CPU 1214C it can exceed 200 ms. The BUSY output protects against re-trigger, but ignoring it (cycling REQ every scan) will generate error 0x0000_81xx (busy) and is a common cause of "empty UDT" complaints.

Reading Multiple Records Sequentially

Real commissioning diagnostics usually need GlobalInfo and PortStatistics from the same switch. The recommended pattern is a state machine that calls each FB in turn, gated on DONE or ERROR of the previous:

CASE "diag_state" OF
    0: // Idle — wait for request
        IF "diag_trigger" THEN
            "db_ReadGlobalInfo"(REQ := TRUE, LADDR := "XC208_HW_ID");
            "diag_state" := 10;
        END_IF;

    10: // GlobalInfo done?
        IF "db_ReadGlobalInfo".DONE THEN
            "db_ReadPortStats"(REQ := TRUE, LADDR := "XC208_HW_ID");
            "diag_state" := 20;
        ELSIF "db_ReadGlobalInfo".ERROR THEN
            "diag_state" := 50;
        END_IF;

    20: // PortStatistics done?
        IF "db_ReadPortStats".DONE THEN
            "diag_state" := 0;
        ELSIF "db_ReadPortStats".ERROR THEN
            "diag_state" := 50;
        END_IF;

    50: // Fault — log and return to idle
        "diag_state" := 0;
END_CASE;

Verification Procedure

1. Compile and download the project. Go online with the controller.
2. Open the instance DB of LPNDR_ReadGlobalInfo in the watch table. Force REQ once.
3. Confirm BUSY rises, then DONE pulses and ERROR stays FALSE.
4. Expand the GlobalInfo UDT — for each occupied port, StationName[n], MacAddress[n], and PortNumber[n] must be non-zero.
5. Cross-check one row against the SCALANCE WBM (Information → Port Statistics and Layer 2 → LLDP). The MAC address must match exactly.
6. Disconnect a device and re-trigger the read. The corresponding array entry should revert to zeros within one cycle.

Troubleshooting Matrix

Version Compatibility Notes

The LPNDR library is republished for each major TIA Portal release. Known releases:

• TIA Portal V15.1 — original release used in the source project
• TIA Portal V16 — current target release (most widely deployed on S7-1500 systems as of 2024–2025)
• TIA Portal V17 / V18 — updated library editions with extended record coverage

Opening a V15.1-era project in V16 with a V16 library will not break the existing FBs, but newer records (e.g. PortMirror, multicast filtering) are only available with the matching library version. Always check the readme inside the ZIP for the exact TIA Portal version the library was compiled against.

Related Documentation

• Siemens Support entry 109753067 – Library for PROFINET data records
• TIA Portal Cloud documentation: Diagnostics and configuration data records
• SCALANCE XC208 operating instructions (WBM chapter Layer 2 → LLDP and Information → Diagnostics)
• SINEC PNI user manual (Primary Network Initialization) for the engineering PC path

FAQ