Simadyn D Spare Parts Reference: Siemens Legacy Module Catalog

1. Overview of the SIMADYN D Control System

The SIMADYN D is a Siemens modular, multiprocessor digital control platform originally developed for high-speed closed-loop control in drive, power-conversion, and process-automation applications. Hardware is packaged in 19-inch sub-racks populated with plug-in modules that communicate over the proprietary high-speed L-bus backplane and S-bus (plus distribution link). Typical deployments include thyristor rectifier control (SITOR), large DC and AC drive regulation, rolling-mill drive line-ups, excitation control for synchronous machines, and turbine governor loops.

The architecture follows a clear separation between the processor layer (PM5), the converter-side interface layer (ITDC, IT41, SE20.2), the field-side binary and analog I/O layer (Econix RMI series), and the synchronization/measurement layer (SA20, SA61, SS52). All modules identified in the spare listing map into one of these layers, which is why a parts catalog must be understood against the system topology rather than as a flat bill of materials.

Effective October 01, 2015, Siemens discontinued the manufacture and supply of the entire SIMADYN D family. After that date, all new-build shipments, factory repairs, and spare-parts manufacturing have formally ceased. The full discontinuation notice is published in the Siemens Industry Online Support portal under entry ID 109475205. Every line item in the spare list below must therefore be treated as a long-life support candidate, not an active catalog product.

2. Discontinuation Timeline and Active Support Window

Siemens announced the phase-out of SIMADYN D with a multi-year pre-discontinuation phase. The relevant lifecycle stages, taken directly from the official discontinuation notice, are summarized below.

From October 2015 onward, every spare-parts transaction for SIMADYN D is effectively a second-source transaction: the part must come from de-commissioned systems, industrial surplus channels, or a small number of independent rebuild houses. This reframes how a maintenance engineer should evaluate the spare list.

3. Sub-Rack, Chassis, and Backplane

The spare list begins with the mechanical layer. Order code 6DD1682-0AJ3 is the sub-rack cover. The SIMADYN D sub-rack is the aluminum chassis that houses the L-bus backplane, the cooling geometry, and the module guide rails. Cover replacement is required when an EMC gasket or paint has degraded in a harsh cabinet (rolling mill pulpit, marine drive room, electrolytic rectifier cell).

The plus distribution link 6QM2200-1 carries the S-bus (synchronization and message bus) between racks. A typical line-up has one S-bus segment per rack with the 6QM2200-1 acting as a tap and terminator. When troubleshooting intermittent rack-to-rack communication, inspect this part first; it is also one of the more failure-prone items because of electrolytic capacitor aging.

4. Processor Module PM5 (32-bit)

Order code 6DD1600-0AJ0 is the processor module PM5, a 32-bit control processor that executes the CFC (Continuous Function Chart) or STRUC G structured-text configuration downloaded through the parallel programmer. The PM5 runs the application cycles, manages the L-bus mailbox, and arbitrates I/O image updates.

Key practical characteristics of the PM5 (consistent with Siemens SIMADYN D manuals and the discontinuation notice):

• Cycle times: 0.5 ms, 1 ms, 2 ms, 5 ms, 10 ms (configurable per task)
• Memory: program memory in EPROM/FLASH; data memory backed by NVRAM (lithium battery on the module)
• Two front-panel diagnostic LEDs: H1 (run) and H2 (fault)
• Front-edge DIP switch selects rack address (0-15) on the L-bus
• Programmed through the parallel programmer (see Section 5)

The PM5 has a known end-of-life symptom: the lithium backup battery discharges after 8-12 years. Once the battery is exhausted, the data memory loses its content on power-down, and the module reports a start-up configuration error. Because factory-replacement PM5 boards are no longer produced, battery replacement must be performed in place using the original battery holder, with a high-quality BR2330 or equivalent cell. Verify polarity and insulate the cell with heat-shrink before reinsertion.

5. SIM-D Parallel Programmer

Order code 6DD1672-0AD0 is the SIM-D parallel programmer, an EPROM/FLASH programming device used to load the compiled configuration onto PM5 (and other processor modules in the family). The programmer connects to a host PC running the STEP7/CFC compiler environment via a parallel (printer-port) link.

The programmer is a critical spare because every PM5 module in the line-up must be loaded with the site-specific configuration at commissioning. Without at least one functional 6DD1672-0AD0 on site, a processor-card swap becomes a 30-day logistics event. Two programmers per site is the conservative target; one is the absolute minimum.

Operational notes:

• The host port is a standard DB-25 parallel interface; modern PCs without an LPT port require a PCI/PCIe parallel add-in card or an industrial-grade USB-to-ECP adapter (with the caveat that some adapters do not honor the strobe-timing that SIM-D uses for write cycles).
• Programmer memory modules (EPROM sockets) wear mechanically after approximately 5,000 insertions. Replace the ZIF socket if intermittent write errors appear.
• Keep the programmer's firmware PROM on file; without the firmware PROM the unit is a brick.

6. Converter Interface Module ITDC

Order code 6DD1601-0AH0 is the converter interface module, designated ITDC. The ITDC is the digital-to-pulse bridge: it accepts set-points and gating patterns from the PM5 processor and generates the firing pulses for the SITOR thyristor stacks. The ITDC also handles current and voltage feedback acquisition on the DC side of the converter.

Two ITDC cables are referenced in the spare list:

• FRC interface cable from ITDC(X5) to RMI201, 20-core FRC, both sides female
• FRC interface cable from ITDC(X6) to RMI201, 20-core FRC, both sides female

Pin mapping for these cables is documented in the SIMADYN D hardware manual; the engineer verifying a faulty ITDC must confirm the cable pin-out before swapping the module, because the X5 and X6 connectors carry different signal sets (X5 is typically the analog feedback, X6 is the binary gating feedback).

7. Synchronization Modules SA20.1 and SA61

Synchronizing-voltage interface modules are the measurement front-end for AC line synchronization. Both modules are essential for line-commutated SITOR converters that must fire in phase with the AC mains:

Both modules take the 100 V or 110 V synchronizing voltage from a voltage transformer and produce a conditioned logic-level phase reference for the ITDC. A drift in the SA20.1/SA61 zero-crossing detector causes a steady-state firing-angle error that is often mistaken for a PM5 control-loop issue. To diagnose, monitor the synchronization input on the ITDC with an oscilloscope and verify that the zero-crossing coincides with the mains zero within the rated accuracy.

8. SITOR Interface Modules and Cables

SITOR is Siemens' thyristor rectifier product family; the SIMADYN D platform is the digital controller that drives it. The SITOR-side interface comprises:

The SE20.2 module is the opto-isolated pulse-amplifier interface between the ITDC and the physical thyristor gates. It converts the logic-level pulse pattern from the ITDC into the high-energy dual pulses required to fire thyristors reliably. A single SE20.2 typically services one six-pulse bridge (6 thyristor gates).

The SC31.2 cable is the screened round cable linking the SE20.2 to the thyristor stack. The screen must be terminated at both ends for EMI suppression. Because the cable carries gate-current pulses with di/dt in the A/µs range, even a partial screen break causes cross-talk between gates and erratic firing. The spare listing shows 7 cables, indicating that the site expects typical gate-cable failure as a recurring event.

The 56 6QN1022-3AD pulse cards reflect the high-failure-rate consumption in a multi-bridge SITOR installation. With nine SE20.2 modules at the SE20.2 side and 56 pulse cards at the stack side, the typical ratio is one pulse card per thyristor position, which is consistent with a 6-pulse bridge configuration with 9 stacks (for example, three 12-pulse line-ups).

9. Econix RMI I/O Family

The Econix RMI series is the binary and analog I/O termination layer for SIMADYN D. The RMI modules are physically located outside the sub-rack, in a marshalling cabinet close to the field devices, and connect back to the ITDC or PM5 via FRC/screened cables.

The RMI201 is the most numerous Econix item in the list, reflecting the high count of pulse-input devices in a SITOR environment (tachogenerators, encoder feedback, pulse-width-modulated valve positioners). The RMI201 connects to the ITDC via dedicated FRC cables on connectors X5 and X6, with 20-core FRC both sides female. A field replacement of an RMI201 does not require processor shutdown, but does require a structured restart of the affected loop because the pulse-count accumulator in the PM5 will momentarily zero.

The RMI101 is the workhorse analog and binary module, providing a mix of 8 digital inputs, 8 digital outputs, 4 analog inputs (typically +/-10 V or 0-20 mA), and 4 analog outputs. It connects to the PM5 via a 10-core FRC cable on connector X5.

10. Cabling Infrastructure

Cables are the single most fragile layer in any legacy SIMADYN D installation. The spare list explicitly enumerates the field-side cable types so the engineer can pre-stage replacements:

When stocking replacement cables, store them flat (not coiled) in anti-static shielded bags at 15-25 degrees C and 30-60 percent relative humidity. FRC connectors suffer insulation resistance drift if stored in high humidity for extended periods; a 24-hour bake-out at 50 degrees C before deployment is a proven field practice.

11. Power Supply and Distribution

The 6QM10321 boost power supply and the 6QM2200-1 plus distribution link together form the rack-internal power and bus distribution. The 6QM10321 is not the main 24 V supply; it is a boost stage that raises the rail voltage to the level required by the SE20.2 firing-output stage. A typical sub-rack has one 6QM10321 per group of three SE20.2 modules.

The 6QM2200-1 plus distribution link carries the S-bus between rack segments. In a multi-rack line-up the S-bus forms a daisy chain. A break in this chain isolates one rack segment and the entire drive becomes incoherent. Always maintain at least two spare 6QM2200-1 modules per site.

12. TTY Converter and Auxiliary Equipment

The TTY converter (manufacturer: Winghe Electronics, 3 units) is a serial-current-loop to RS-232 level shifter used to interface SIMADYN D service consoles and HMI panels. Although the manufacturer is third-party (not Siemens), the converter is mechanically and electrically keyed to the SIMADYN D rack and is not interchangeable with generic TTY converters. Confirm that any replacement TTY converter is rated for 20 mA current loop and 9600 baud minimum, with optical isolation on the loop side.

The Canopus 5-channel adder amplifier (4 units) is an external signal-conditioning device that sums up to 5 analog signals into a single output for the SIMADYN D analog input. This is typically used to combine load sharing signals from multiple drives or to add a feed-forward term in a master/follower configuration.

13. Sourcing Strategy After the 2015 Discontinuation

Because the official supply channel ended October 01, 2015, every spare-parts acquisition must follow one of three practical sourcing paths. Each path has different risks, lead times, and verification requirements.

For the highest-volume items (PM5 6DD1600-0AJ0, ITDC 6DD1601-0AH0, SE20.2 6DD1681-0CA2, and the 6QN1022-3AD pulse card), the prudent engineering practice is to maintain a strategic stockpile equal to 12-24 months of historical consumption. For lower-volume items (SS52 6DD1684-0DB2, SA20.1 6DD2920-0AR6, SA61 6DD2920-0AR1), a 6-12 month stockpile is acceptable provided a confirmed rebuild-house source is on file.

14. Commissioning and Verification Procedure for Re-sourced Spare PM5

When a spare PM5 is acquired from any non-factory source, the following bench verification procedure should be performed before the module is installed in a live rack.

1. Inspect the lithium battery holder. If the cell is original, replace it with a fresh BR2330 (or equivalent) before applying power.
2. Install the PM5 in a known-good test rack with the L-bus terminated.
3. Apply 24 VDC. Verify both LEDs illuminate briefly during the POST (power-on self-test).
4. Confirm the H1 LED is steady green (run) and H2 LED is off within 10 seconds.
5. Connect the SIM-D programmer (6DD1672-0AD0) and read the current configuration. If the configuration is blank or corrupted, reload from the master backup.
6. Perform a 24-hour burn-in at 40 degrees C ambient.
7. Re-read the configuration to confirm NVRAM retention.

If the PM5 passes all seven steps, it is cleared for service. Record the test result in the spares inventory database.

15. Migration Paths and Successor Platforms

Siemens did not publish a direct drop-in successor for SIMADYN D, but the typical migration paths documented in industry practice are:

• SIMATIC TDC (Technology and Drive Controller) - the closest functional successor, sharing many of the same CFC programming concepts but on a newer hardware platform.
• SINAMICS SIMOTION - for motion and drive-centric applications, particularly new SINAMICS drive line-ups.
• SIMATIC S7-1500 with TM PTO/TMC - for smaller closed-loop applications where the cycle time can be relaxed.

Migration projects require a complete re-implementation of the CFC configuration in the successor toolchain; there is no automated converter. For installations where a migration is not feasible, the only sustainable path is the disciplined spare-parts strategy described in this article.

16. Troubleshooting Matrix for Common Field Symptoms

17. Frequently Asked Questions