Setting the PROFIBUS DP Address on a SIMOTION D435-DP After Controller Replacement

A SIMOTION D4x5-2 DP variant (including the D435-DP in the field case below) stores its PROFIBUS DP station address in non-volatile device memory. When the controller is replaced in the field, the new unit ships with no DP address - even if the SD card is transferred from the old unit. The address must be set in SIMOTION SCOUT (or TIA Portal with the SCOUT plug-in) inside HWConfig, and the project must be downloaded to the new controller. This article documents the exact procedure, the underlying reason, the verification steps, and the integration path with an Omron NJ301-1100 master via a CJ1W-PRM21 PROFIBUS module.

1. Problem Statement and Field Case

After swapping a failed SIMOTION D435-DP for a new unit, the engineer reports the following symptoms:

• The new controller executes the user program from the SD card correctly.
• The local HMI (directly attached to the D435-DP) shows the application running and accepts operator input.
• The Omron NJ301-1100 (Sysmac NJ series) controller on the plant network cannot see the D435-DP on the PROFIBUS DP segment.
• Other plant HMIs that normally exchange data with the D435-DP also report the device as missing.
• Power cycling the D435-DP and the Omron NJ does not restore communication.
• The "I'm here" / heartbeat signal from the D435-DP never reaches the master, so the application logic that depends on this signal (typically a cyclic bit at a defined offset in the I/O image) never trips.

2. Affected Hardware, Firmware, and Engineering Tools

Primary reference: SIMOTION D4x5-2 Commissioning Manual (Siemens entry ID 61189579). Page 105 (Commissioning / hardware) explicitly states that the IP/DP address previously set in the device is deleted when the unit is replaced, and must be re-assigned during commissioning.

3. SIMOTION D4x5-2 Family Reference

The D4x5-2 family is the second-generation SIMOTION drive-based controller. The hardware variants differ in axis count and the integrated fieldbus interface:

The "-DP" suffix in the order number (or the "DP" mark on the front panel) indicates the presence of the integrated PROFIBUS DP interface on X136. This is the interface whose station address must be set in HWConfig for the troubleshooting case described here. The "-PN" variants use PROFINET only and do not have X136 - in that case the address concern is PROFINET device name resolution via DCP, not a PROFIBUS address.

4. Root Cause: Why the DP Address Is Lost on a New Device

PROFIBUS DP station addresses on a SIMOTION D4x5-2 are configured parameters, not auto-negotiated values. PROFIBUS DP does not provide a DCP-like auto-assignment mechanism (in contrast to PROFINET). Each station must be assigned a unique address by the engineering tool and downloaded to the device. The PROFIBUS address is stored in the device's non-volatile configuration memory, separate from the runtime project that lives on the SD card.

When a D4x5-2 controller is replaced:

1. The new unit ships with no PROFIBUS DP address set.
2. The SD card from the old unit contains the runtime project, technology packages, and retain data, but not the DP station address.
3. The runtime boots, executes the user program, and answers to the local HMI over the integrated PROFINET/Ethernet service interface (X120 / X130).
4. The PROFIBUS DP interface (X136) remains silent because its station address is undefined. The DP master's polling list does not match any live station at that address, so the master reports the D435-DP as missing.

This is the exact scenario the SIMOTION D4x5-2 Commissioning Manual describes on page 105: the previously set IP/DP address is no longer valid on the new device and must be re-assigned.

5. Required Tools, Software, and Materials

• SIMOTION SCOUT V4.x or V5.x (or TIA Portal with the SCOUT add-in), installed and licensed.
• Original project archive: a .zip or unzipped SIMOTION project folder containing the HWConfig and the technology objects / programs.
• PG/PC interface to reach the D435-DP. Two options are supported by the D4x5-2:
  • Industrial Ethernet (TCP/IP) over X120 or X130 service port. Use a standard Ethernet cable and assign the PG/PC a fixed IP in the same subnet (e.g., 169.254.11.22 with the controller default 169.254.11.10). This is the recommended path.
  • PROFIBUS DP via a Siemens PC adapter (e.g., 6GK1571-1BA00) or CP 5512 / CP 5611 / CP 5612 PCI card, connected to the bus.
• Plant documentation: the PROFIBUS DP station address previously used by the D435-DP (e.g., 3, 12, or whatever the master is configured to poll). This must match the slot the master is configured to poll - the project cannot auto-discover it.
• Master-side configuration: the GSD file for SIMOTION D (Siemens vendor ID 0x0150) installed in the Omron CX-Configurator FDT for the CJ1W-PRM21.
• USB or Ethernet cable suitable for the PG/PC interface, plus administrator rights on the engineering PC to install drivers for Siemens PC adapters.

6. Step-by-Step: Setting the DP Address in HWConfig

1. Open the project in SCOUT. Launch SIMOTION SCOUT, then Project > Open. Browse to the original project archive and open it. If the project is part of a SIMATIC multi-project (e.g., combined with a SIMATIC S7 controller), open the multi-project root.
2. Open HWConfig. In the project tree, double-click the SIMOTION D4x5-2 device node. This launches the hardware configuration (HWConfig) editor, which uses the same UI as SIMATIC S7-300 station configuration. The rack view shows the integrated CPU, the integrated drive control (CX slots), and the fieldbus interfaces.
3. Locate the integrated DP interface. On a D4x5-2 DP variant, the PROFIBUS DP interface is shown as "DP" on the rack, with the order number suffix "2AD" or similar. The corresponding physical connector is X136 on the front panel of the controller.
4. Open the DP interface properties. Double-click the DP interface module. The Properties dialog opens.
5. Set the station address. In the Properties dialog, navigate to the "Parameters" tab. Enter the PROFIBUS DP station address that matches the slot the Omron PRM21 master is configured to poll (for example, "3"). The address must be unique on the segment.
6. Verify the bus profile and baud rate. In the same dialog, confirm the bus profile (DP, DPV1, DPV2) and the baud rate (1.5 Mbps is the typical default for motion applications, with 3 Mbps, 6 Mbps, and 12 Mbps also supported). All stations on the segment must use the same baud rate. The PROFIBUS standard (IEC 61158 / IEC 61784) supports 9.6 kbps up to 12 Mbps.
7. Configure the DP mode. The D4x5-2 DP can act as a DP slave (most common when paired with a higher-level controller) or as a DP master (when the SIMOTION itself is the master of subordinate drives or I/O). Confirm the role matches the plant design.
8. Compile and save. Use Station > Save and Compile in HWConfig. SCOUT will warn if there is a station address conflict with another slave in the project.
9. Download the hardware configuration to the target. Right-click the SIMOTION station in HWConfig and select "Download to Target System." Select the PG/PC interface (Industrial Ethernet TCP/IP is preferred for the service port) and confirm. If SCOUT warns about an online/offline project ID mismatch (expected after a hardware replacement), confirm and proceed.
10. Restart the controller if prompted. SCOUT will report whether the new address requires a STOP-to-RUN transition or a power cycle. Some firmware versions accept the new address on the fly; others require a restart.
11. Persist the project to the SD card. After the download, transfer the project to the SIMOTION's persistent storage (Target System > Copy RAM to ROM, or equivalent) so the address is also preserved across future power cycles. The runtime project on the card should match the device's non-volatile configuration.

7. Step-by-Step: Online Commissioning Without the Original Project

If the original SCOUT project archive is unavailable, the DP address can still be written to the new D435-DP by going online directly. This recovery path is documented on page 105 of the SIMOTION D4x5-2 Commissioning Manual:

1. Connect the PG/PC to the D435-DP's service Ethernet port (X120 or X130) using a static IP in the controller's subnet.
2. In SCOUT, choose Project > Accessible Nodes (or PLC > Accessible Nodes in older versions). SCOUT will broadcast a discovery on the Ethernet subnet and list any SIMOTION devices it finds, along with their current IP address and DP address (or "not assigned").
3. Select the D435-DP node and click "Online." Accept any project ID mismatch warning.
4. Navigate to the device's hardware configuration view and open the DP interface properties (X136).
5. Enter the correct station address and save. The address is written to the device's non-volatile memory.
6. After the address is set, rebuild the project as soon as possible so that the project archive on the engineering PC matches the device configuration. Without the archive, future downloads to the unit will use default parameters and may overwrite the address.
7. Verify the link as described in section 8.

8. Verifying the PROFIBUS Link

1. Check the DP interface LEDs on the D435-DP. The integrated DP port (X136) has a "BF" (Bus Fault) LED. After correct configuration, the BF LED should be off, indicating that the slave is being polled on the bus.
2. Use SCOUT's HWConfig online diagnostics. In HWConfig, click PLC > Online > Diagnostics, or Station > Online. The PROFIBUS DP subnet view lists every detected station with its address, status (green/OK, red/fault), and the master's view. The D435-DP should appear at the configured address with a green status.
3. Verify from the master side. On the Omron side, open CX-Configurator FDT and confirm that the SIMOTION slave is now visible at the expected address. The CJ1W-PRM21 module should report the slave as "Data Exchange" (DX) on the assigned slot.
4. Test the application handshake. Force a small cyclic data read or trigger the application-level "I'm here" bit from the SIMOTION side and confirm the Omron NJ301-1100 receives it in its allocated I/O area. The application should now resume normal operation.
5. Inspect the diagnostic buffer. In SCOUT, open the SIMOTION diagnostic buffer (Target System > Diagnostic Buffer). The most recent entries should show PROFIBUS state transitions (e.g., DP slave going to "Data Exchange"). No new bus faults should be present.
6. Check the diagnostic repeat counter on the master side. If the CJ1W-PRM21 reports a non-zero repeat counter for the SIMOTION slot, the segment has wiring or termination issues independent of the address. Address those first.

9. LED and Diagnostic State Matrix

10. Master-Side Commissioning on the Omron NJ + CJ1W-PRM21

The NJ301-1100 belongs to Omron's Sysmac NJ family and natively supports EtherNet/IP on its built-in port. It does not include an integrated PROFIBUS DP interface, so a PROFIBUS DP segment with a SIMOTION D4x5-2 DP requires one of the following topologies:

• A CJ-series PROFIBUS master module (e.g., CJ1W-PRM21) installed on a CJ rack behind the NJ. The NJ exchanges data with the CJ over the backplane, and the PRM21 polls the SIMOTION slave on PROFIBUS DP. This is the typical production path.
• A third-party PROFIBUS-to-EtherNet/IP gateway. This is uncommon for high-speed motion data because of added latency, but it can be used for slow supervisory data.

In the field case, the most likely topology is an NJ301-1100 with a CJ1W-PRM21 master on a CJ rack. The commissioning tasks on the Omron side after the DP address is set on the SIMOTION:

1. Install the SIMOTION GSD file (vendor ID 0x0150 for Siemens, device family "SIMOTION D") into CX-Configurator FDT. Use the GSD revision that matches the SIMOTION firmware to avoid diagnostic or parameter mismatches.
2. Add the SIMOTION D4x5-2 DP slave to the PROFIBUS configuration at the matching station address (the same one just set in HWConfig on the SIMOTION side).
3. Map the I/O slots of the SIMOTION slave into the CJ I/O table. Typical motion applications map process data words (control word / status word, actual position, actual velocity, etc.) into fixed offsets that the NJ reads via the backplane.
4. Build and download the CJ configuration. After the download, the PRM21 should show the SIMOTION slave in "Data Exchange" (DX) mode at the new address. The PRM21 module's "RDY" LED turns green when the segment is healthy.
5. In Sysmac Studio, allocate the CJ I/O areas mapped to the PRM21 to NJ variables using the CJ Unit configuration. Test the heartbeat / "I'm here" signal in a small ladder or ST routine on the NJ side.

11. Network Topology (Inline SVG)

12. PROFIBUS Bus Parameters

The bus parameters used in HWConfig for SIMOTION D4x5-2 follow the PROFIBUS DP standard (IEC 61158 / IEC 61784). The most relevant values:

For deeper reference on the bus protocol, see the PROFIBUS Nutzerorganisation documentation (PI - PROFIBUS & PROFINET International) and the IEC 61158 / IEC 61784 series. The SIMOTION D4x5-2 Commissioning Manual is the primary Siemens-side reference for setting the DP address and the overall commissioning workflow.

13. Common Pitfalls and Edge Cases

• SD card does not set the DP address. A common misconception is that the SD card "is the configuration." It contains the runtime project and retain data, but the DP station address is a device-level parameter that is written during a hardware download from SCOUT.
• Mismatched baud rate. If the rest of the segment is at 12 Mbps and the new device is at default 1.5 Mbps, the slave is invisible. Set the baud rate in HWConfig to match the segment before downloading.
• Address collision. Two slaves with the same address cause intermittent communication failures. SCOUT warns at compile time, but if the master was configured offline, the conflict shows up only at runtime as stations going in and out of comms.
• Wrong interface selected during download. The D4x5-2 has multiple Ethernet ports (X120 service, X130 PROFINET) and one PROFIBUS port (X136, on the -DP variant). Confirm that the engineering download is going to the service interface and that the address is being written to the PROFIBUS interface, not PROFINET.
• Missing PROFIBUS termination. The segment must be terminated at both physical ends (typically via switches on the D-sub connectors or on the master module). Missing terminators produce bus errors that mask other issues.
• Project ID mismatch after replacement. SCOUT will report an online/offline project ID mismatch after a hardware replacement. This is expected and not a fault - it simply means the device has been replaced. Confirm the download.
• Wrong version of the GSD file on the master. If the Omron PRM21 was configured with an older GSD revision of SIMOTION, newer diagnostic or parameter data may not be exchanged correctly. Re-import the latest Siemens GSD (vendor 0x0150, SIMOTION D) into the PRM21 configuration.
• Retain data is from the old unit. If the SD card was transferred, retain data is from the previous unit. If the application uses retain variables that depend on hardware serial numbers or slot assignments, validate the values before resuming production.
• PROFINET vs PROFIBUS confusion. Engineers often confuse the two. PROFINET uses device names (resolved by DCP), PROFIBUS uses numerical station addresses (1-127). The D4x5-2 DP variant has both a PROFINET port (X130) and a PROFIBUS port (X136); setting the PROFINET device name does not set the PROFIBUS address.
• License / technology package mismatch. If the new D4x5-2 ships with a different license or technology package set, the runtime may refuse to start or skip the DP interface. Verify the technology packages on the SD card match the new device's license.

14. Safety, Lockout, and Validation

When working on a SIMOTION-driven machine, the motion paths are live as soon as the controller enters RUN. Before downloading a configuration that affects PROFIBUS communication:

1. Place the machine in a safe state (operator stop, gate closed, drives disabled) per the site's risk assessment.
2. Engage the safety relay / STO chain so that the drives cannot produce motion regardless of controller state.
3. Disable the application's use of the PROFIBUS data (e.g., a software interlock) so that the momentary loss of cyclic data does not trigger a dangerous response.
4. Perform the address change and the hardware download.
5. Validate the link using the steps in section 8, including the application-level "I'm here" handshake.
6. Restore the application interlock and re-enable drives in a controlled, staged manner (jog at low velocity, then production speed).

SISTEMA / SIL considerations: PROFIBUS DP is not a safety bus by itself. Safety I/O (PROFIsafe) is a separate layer that uses PROFIBUS as a black channel. If the affected controller participates in a PROFIsafe network, coordinate the commissioning with the safety engineer and re-validate the safety function after any change.

15. Firmware and Software Compatibility

When downloading the project to the new D4x5-2, the SCOUT version and the SIMOTION firmware version on the SD card must be compatible. The general compatibility matrix (consult the SIMOTION D4x5-2 Commissioning Manual and the SCOUT release notes for the exact mapping):

If the new D4x5-2 ships with a different firmware version than the SD card was built for, perform a firmware update on the new device before downloading the project. SCOUT will warn if the firmware on the device does not match the project's expected runtime version. The D4x5-2 supports firmware update via the SD card (Target System > Update Firmware) or via SCOUT's online update.

16. Field Recovery Cheat-Sheet

1. Open the original SCOUT project and double-click the SIMOTION D4x5-2 to launch HWConfig.
2. Open the integrated DP interface (X136) properties.
3. Enter the same PROFIBUS DP station address that the previous unit used, matching the master's polling list (e.g., the slot configured on the CJ1W-PRM21).
4. Confirm the bus profile, baud rate, and DPV1/DPV2 mode match the rest of the segment.
5. Compile and save the HWConfig, then download to the target via the service Ethernet port (X120 or X130).
6. Restart the controller if SCOUT prompts for it; copy RAM to ROM so the address is persisted to the SD card.
7. Verify with the BF LED on X136, HWConfig online diagnostics, and the master's slave list. Confirm the application-level "I'm here" handshake resumes.
8. If the original project is unavailable, use SCOUT's "Accessible Nodes" path to go online and write the DP address directly. Then rebuild the project as soon as possible so the engineering archive matches the device configuration.

The underlying behavior is documented in the SIMOTION D4x5-2 Commissioning Manual, page 105.