SINAMICS G120C PN: Parameter Sets, ROM, and Memory Card Backup

Overview

The SINAMICS G120C PN is a compact, wall-mount frequency inverter from the SINAMICS G120 family, designed for industrial applications requiring PROFINET connectivity. The "C" variant integrates the Control Unit (CU) and Power Module (PM) into a single housing, reducing cabinet footprint and wiring effort. The PN suffix designates the PROFINET-based Control Unit (typically CU240E-2 PN for standard applications or CU250S-2 PN for safety and encoder-based control), which manages all closed-loop regulation, fieldbus communication, and parameter storage for the drive.

The drive stores its parameter image in non-volatile memory (ROM) and can additionally use a plug-in SINAMICS SD card for backup, device cloning, and firmware updates. Mastering the four ROM-backed parameter sets — 0, 10, 11, and 12 — is essential when an application must store and switch between multiple complete drive configurations. This reference consolidates the parameter-set model, the RAM-to-ROM workflow, the memory card transfer procedure, and the recommended commissioning sequence into a single field-ready document.

References used in this article:

• SINAMICS G120 List Manual — parameter dictionary and p0804 value table.
• SINAMICS G120C Commissioning Manual — commissioning workflow with p0340, p1900, p1910, p1960.
• SINAMICS General Drive G180 — SITRAIN course — hands-on training for the G120 family.

Control Unit Variants and Memory Architecture

The G120C PN ships with one of several Control Unit types. The CU240E-2 PN and CU250S-2 PN are the most common, differing in I/O count, encoder support, and integrated safety functions (STO, SS1, SLS on the CU250S-2). All variants share the same parameter storage model:

• Volatile memory (RAM) — holds the active parameter image that the drive is currently running.
• Non-volatile memory (ROM) — holds four parameter sets numbered 0, 10, 11, and 12.
• Optional SINAMICS SD card — provides three additional storage slots (also numbered 10, 11, 12) plus the device firmware and project file.

Parameter set 0 is the default set loaded at power-up. It is also the automatic target of every RAM-to-ROM save initiated by the IOP/BOP, Startdrive's "RAM to ROM" button, or the SINAMICS web server. Sets 10, 11, and 12 are user-defined backup slots that can each hold an independent snapshot of a fully commissioned parameter set, including all configured Command Data Sets (CDS) and Drive Data Sets (DDS).

Parameter Set 0 vs. Sets 10, 11, 12

The four ROM-backed parameter sets are independent snapshots, not layered overrides. The active image is the one currently in RAM, and the drive selects which ROM set to load at power-up based on internal rules (default: set 0).

When a project requires two entirely different drive parameterizations — for example, a pump curve profile and a conveyor profile, each with its own CDS and DDS structure — store one in set 0 and the other in set 10. The desired set is loaded into RAM at runtime by writing the set number to p0971 (for example, p0971 = 10 to load the alternate profile) or via a control-word bit if the higher-level controller triggers the switch over PROFINET.

Command Data Sets (CDS) and Drive Data Sets (DDS)

Every SINAMICS G120C supports multiple Command Data Sets and Drive Data Sets. The number of each is configurable:

• CDS — Command Data Set. Contains command and setpoint source settings: which PROFINET telegram controls the drive, source of speed setpoint, digital input configuration, ramp-function generator settings tied to the active command source. The number of available CDS is set by p0170 (factory default: 1, max: 3 on G120C).
• DDS — Drive Data Set. Contains the motor and closed-loop control parameters: motor nameplate data, controller gains, ramp-up/ramp-down times, current/voltage limits, fault responses, and similar. The number of available DDS is set by p0180 (factory default: 1, max: 4 on G120C).

A single ROM parameter set (0, 10, 11, or 12) contains the complete parameter image, including all configured CDS and DDS entries. Saving to set 10 stores every CDS/DDS pair that exists at that moment, not just one. To switch CDS at runtime, use the control word bits defined for CDS selection; to switch DDS, use the corresponding control word bits or p0820. The drive will copy the appropriate sub-set from ROM into RAM on the next transition.

Saving Parameters to ROM (p0971)

Parameter p0971 is the master control for non-volatile save operations. It is the only parameter you need to learn for the basic RAM-to-ROM workflow.

Procedure from the IOP/BOP or Startdrive:

1. Ensure the drive is in "Ready" state (no fault, no run command active).
2. Set p0971 to the desired target value (1, 10, 11, or 12) and press OK / Set.
3. Wait several seconds. The drive flashes the save-in-progress indicator.
4. Do not power-cycle the drive while p0971 ≠ 0. Removing power mid-write can corrupt the ROM.

To back up the currently active configuration before changes, write the RAM image to set 10 first (p0971 = 10), then make the changes and write the new image to set 0 (p0971 = 1). Both writes must be triggered explicitly; one does not follow from the other.

Memory Card Operations (p0802, p0803, p0804)

The optional SINAMICS SD card extends the drive's storage with three additional slots numbered 10, 11, and 12. The slot numbering is reused and is independent of the ROM set numbering — a card slot and a ROM set are not the same thing. The card can hold:

• The drive's firmware image (used for firmware update / downgrade)
• A complete parameter file keyed to the Control Unit article number (used for device cloning)
• Up to three user snapshots in slots 10, 11, 12 (used for backup of ROM sets)

Parameters p0802, p0803, and p0804 control all data movement between the card and ROM.

Standard procedure to back up ROM set 0 to memory card slot 10

1. Insert the SINAMICS SD card into the drive.
2. Set p0802 = 10 — target slot on the card.
3. Set p0803 = 0 — source ROM set.
4. Set p0804 = 2 — start the copy from ROM to card.
5. Monitor r0804. The transfer takes a few seconds; r0804 returns to 0 when done.
6. Do not remove the card while p0804 ≠ 0 or while the drive is still writing.

Standard procedure to restore a memory card slot to a ROM set

1. Set p0802 = source slot on the card (e.g., 10).
2. Set p0803 = target ROM set (e.g., 0).
3. Set p0804 to the appropriate card-to-ROM transfer value (refer to the List Manual p0804 table for the current SINAMICS G120 firmware revision).
4. Wait for completion; confirm by reading back the destination ROM set.

Reference: See the SINAMICS G120 List Manual for the full p0804 value table and worked examples for every transfer direction.

Auto-Save Behavior on Memory Card Insertion

When a memory card is inserted into an unconfigured drive, the drive inspects the card for a valid parameter file. The file is keyed to the Control Unit article number (for example, 6SL3246-0BA22-1PA0 for a CU240E-2 PN). If the article number matches the inserted CU, the drive offers to copy the file into RAM. After you accept, the parameters are written to RAM; a subsequent RAM-to-ROM (p0971 = 1) commits them to ROM set 0.

Only parameter set 0 is the automatic target on a card import. Card slots 10, 11, and 12 are not auto-loaded into ROM. They must be copied explicitly using p0802/p0803/p0804, as described above. Likewise, p0971 alone does not push the RAM image to the card; it pushes to ROM only.

Commissioning Workflow with p0340, p1900, p1910, p1960

Once the wiring is complete, the motor connected, and PROFINET online, the recommended commissioning sequence is:

1. Enter motor nameplate data into the drive:

2. Set p0340 to control the parameter calculation:

For a brand-new commissioning, p0340 = 1 is the standard choice. If you only want the SINAMICS to compute motor/controller parameters but leave inverter-side data (such as modulation limits or switching frequency) at their defaults, use p0340 = 3. If you provide all controller gains manually, set p0340 = 0.

3. Run stationary motor identification with p1910 = 1, then issue an ON command (via Startdrive, the BOP, or PROFINET control word). The drive measures stator resistance, leakage reactance, and IGBT dead time, but the motor shaft does not rotate.
4. Run rotating motor identification with p1960 = 1, then issue an ON command. The drive accelerates the motor through a defined speed profile to tune the speed controller, friction compensation, and moment of inertia estimate.
5. Optimize the speed controller with p1900 = 1 (typically used in conjunction with p1960) for one-button automatic optimization.
6. Save to ROM with p0971 = 1 (or 10/11/12 for a specific backup slot).

Use of Startdrive in TIA Portal

Startdrive is the engineering tool for SINAMICS drives integrated into the TIA Portal. Two main operations apply to the G120C PN:

• Download to device — connects to the drive over PROFINET and writes the offline parameter set to RAM. The project remains volatile until a save-to-ROM is performed.
• RAM to ROM — Startdrive's toolbar button writes the active RAM image to ROM set 0. Equivalent to writing p0971 = 1. To target sets 10/11/12, write p0971 directly from the parameter list or the drive's web server.

To back up the project to the SINAMICS SD card, use Startdrive's "Load to memory card" function in the project tree. The drive's SD slot is not directly exposed to the PC: the card must either be removed and read with a card writer, or Startdrive can stream the file through the live online connection to the drive. A CPU-style drag-and-drop of a TIA project file onto the SD card is not the correct procedure for SINAMICS — the drive expects a single, proprietary parameter file keyed to the CU article number, not a TIA project archive.

Verification

After saving parameters and (if applicable) copying them to the memory card, run the following checks before handing the drive over to production:

1. Power-cycle the drive and confirm that parameter set 0 (or the intended set) reloads correctly. The drive should return to "Ready" within a few seconds of power-up.
2. Read r3925 ("Commissioning state"). r3925 = 0 means commissioning is incomplete; r3925 = 1 means p0340 ≥ 1 has been executed and saved.
3. For p0804 operations, monitor r0804 (transfer status). r0804 returns to 0 only after the transfer is complete; do not remove the card or write further p0802/p0803/p0804 values while r0804 ≠ 0.
4. To confirm a memory card backup, remove the card, insert it into a second G120C with the same Control Unit article number, and verify that the parameters load cleanly. If the second drive refuses the file, the Control Unit article numbers do not match.
5. From PROFINET, send a CDS switch and a DDS switch via the appropriate control word bits and confirm that the drive responds with the corresponding status word changes.

Troubleshooting Matrix

Frequently Asked Questions