Overview
The SINAMICS G120 modular drive family supports up to four Command Data Sets (CDS), identified by parameter indices .00, .01, .02, and .03. Each CDS carries its own copy of every command-source parameter (setpoints, ramp generators, fixed setpoints, jog settings, references, control word bits, etc.), which lets one physical drive switch between two or more independent control configurations without reloading parameters from a commissioning tool.
Switching CDS is normally used for Manual/Automatic changeover, local/remote operation, or for alternating between two operator panels. The currently active CDS is selected by parameter P0810, and a copy of the same value is mirrored into r0050 for diagnostics.
The challenge addressed in this article: an engineer needs to edit a parameter value inside CDS1 (for example P2106[1]) using the Intelligent Operator Panel (IOP) rather than STARTER or Startdrive. The IOP always opens a parameter on the currently active CDS, so when CDS0 is active the editor only shows the .00 index. Switching the panel display over to a different CDS requires either activating that CDS through P0810 or using the IOP's dataset selection menu.
Both methods are documented in the official Siemens knowledge base entry SINAMICS G120: Switching over a command data set using the IOP (KB ID 106551863) and are reproduced below in field-procedure form.
Prerequisites
| Item | Requirement | Notes |
|---|---|---|
| Control Unit | CU240E-2 DP | Also valid for CU240E-2, CU240E-2 F, CU250S-2 with IOP |
| Firmware | V4.4 (or compatible 4.x branch) | CDS structure identical across G120 V4.x |
| IOP firmware | V1.4 (or IOP-2) | IOP-2 supports the same menu path with touch navigation |
| Drive state | Drive may be in any state | Parameter edits do not require "Ready" or "Run"; some online writes trigger A07929 |
| Access level | P0003 = 3 (Expert) recommended | Index editor is hidden at Standard level for some parameters |
| CDS enabled | Number of CDS configured in P0810 use, P0820 use (DDS) | P0182 = number of CDS configured (default 1, can extend to 4) |
Command Data Set Architecture in SINAMICS G120
Every command-source parameter in the G120 has multiple indices that mirror the active CDS. Index .00 belongs to CDS0, .01 belongs to CDS1, and so on. Only the active CDS is read by the drive's runtime; inactive CDS indices remain stored but are not executed.
| Index | Data set | Typical use case |
|---|---|---|
| .00 | CDS0 | Automatic / PROFIBUS control |
| .01 | CDS1 | Manual / IOP / terminal control |
| .02 | CDS2 | Optional (must be enabled via P0182) |
| .03 | CDS3 | Optional (must be enabled via P0182) |
The selection itself is performed by P0810, a bit-pattern parameter whose bit values are evaluated as binary encoded CDS number:
| P0810 value (binary) | Active CDS |
|---|---|
| 0 | CDS0 |
| 1 | |
| 2 | CDS2 |
| 3 | CDS3 |
Most control units map P0810 to a digital input (BI of P0810[0]) or to a PROFIBUS/PROFINET control word bit. The default on CU240E-2 DP is digital input DI 4 (CDS bit 0) and DI 5 (CDS bit 1) via the BICO interconnection in p0820 / p0821.
Diagnostic readback is performed via r0050 (CDS active) and r0051 (DDS active). Always verify with these readback parameters after a CDS change to confirm the drive has actually switched.
Method 1: Switch the Active CDS Through the IOP Menu
This is the official Siemens-documented procedure for changing the default data set shown in the IOP editor. It temporarily sets the IOP's display focus to a specific CDS so you can edit any indexed parameter inside that data set.
- From the IOP main status screen, press the MENU button.
- Navigate to Options (on IOP-2 the tile is labeled "Options"; on IOP with wheel use the lower soft-key "Options").
- Open Parameter settings.
- Select Default data set.
- Select Command data set. The drive offers three options as listed in KB 106551863:
| Menu choice | Effect |
|---|---|
| CDS0 | IOP editor opens parameters on index .00 (default) |
| CDS1 | IOP editor opens parameters on index .01 |
| Do not change data set | Keeps the current IOP focus without modifying drive behavior |
- Choose CDS1. The IOP confirmation screen appears.
- Press OK on the wheel (or tap the check mark on IOP-2). The status bar at the top-left of the display now shows CDS1.
- Press MENU → Parameters and search for
P2106. - Push the wheel to OK. The IOP now opens
P2106[0..n]and the current index editor defaults to.01. - Use the wheel to scroll to
.01if it is not already selected, press OK on the index field, edit the value, and confirm.
P0810, and it does not force the drive runtime to switch to CDS1. The drive continues to use whichever CDS is active per P0810.Method 2: Activate CDS1 via P0810 Before Editing
Use this method when the drive itself must run on CDS1 (for example when validating a Manual/Automatic handover) and you also want to verify the parameter values in that dataset.
- From the IOP, press MENU → Parameters.
- Navigate to
P0810and press OK. - Set the value to
1(selects CDS1) and confirm with OK. - Return to the status screen. The top-left indicator should now display CDS1, and
r0050should read1. - Search for
P2106. The IOP now opens the.00index of CDS0 by default; press OK on the parameter, then press OK on the index field, scroll to.01, press OK, and edit the value.
If the CDS does not switch after writing P0810 = 1, check the BICO source: P0810 is interconnected to a digital input or PROFIBUS control-word bit. The runtime value of P0810 is the OR-combination of all BI sources, so an active DI4 (default BICO) can override a manual write. Open r0810.0 on the IOP to read the live source value.
Editing an Indexed Parameter on the IOP
Once the IOP is focused on the correct CDS, every indexed parameter follows the same editing pattern. The behavior is described in the SINAMICS G120 operating instructions and reproduced here.
- In the parameter search screen, enter the parameter number (for example
2106). - Press OK. The parameter detail screen appears; the index field currently displays the index tied to the active CDS or to the CDS selected in Method 1.
- Press OK on the index field. The index becomes editable (the field is highlighted).
- Rotate the wheel to scroll through the available indices
.00,.01,.02,.03until the target index is displayed. - Press OK to confirm the index. The value field becomes editable.
- Rotate the wheel to set the value, or use the numeric keypad on IOP-2.
- Press OK to commit. The IOP shows the new value and a green check mark.
Verifying the CDS Change
After completing the edit, confirm three independent indicators before handing the drive back to production:
| Check | Action on IOP | Expected result |
|---|---|---|
| IOP status bar | Return to status screen | Top-left shows "CDS1" |
| r0050 (CDS active readback) | Search parameter r0050 | Returns 1 |
| r0810 / r0051 cross-check | Search r0810 and r0051 | Drive accepts new CDS; no fault F07300 |
| Written value persisted | Re-open P2106 | Displays the new value at index .01 |
| RAM-to-ROM (optional) | MENU → Memorize / RAM→ROM | Save retained across power-cycle |
If r0050 does not return 1 after writing P0810 = 1, the BICO source is overriding the manual change. Either disconnect the DI4 source (open p0820[0] and p0821[0]) or change the CDS via the digital input that is wired to the BI of P0810.
Troubleshooting Matrix
| Symptom | Likely cause | Remedy |
|---|---|---|
| IOP only shows CDS0 regardless of selection | P0182 = 1, only CDS0 enabled | Set P0182 to number of CDS required (max 4) and power-cycle |
| Index field is greyed out on parameter screen | P0003 access level too low | Set P0003 = 3 (Expert) |
| Value writes but reverts after power cycle | Not saved to non-volatile memory | Run RAM→ROM from IOP menu or set P0971 = 1 |
| F07330 fault after CDS switch | Selected CDS not configured | Verify P0182 ≥ required CDS index + 1 |
| r0050 stays at 0 after writing P0810 = 1 | BICO source on P0810 overrides value | Open p0820[0] / p0821[0]; ensure DI source matches desired state |
| A07929 appears during write | Parameter cannot be changed in current operating state | Bring drive to "Ready to switch on" (r0002 = 0x0C) and retry |
| IOP shows "ACCESS DENIED" | Parameter write-protected by P0927 or BOP/IOP access level | Check P0927 = 1 for I/O enabled |
| CDS1 values lost after firmware update | Parameter set not backed up before update | Use STARTER/Startdrive save function; IOP backup through MENU → Up/Download |
Related Parameters for CDS Configuration
| Parameter | Description | Default | Comment |
|---|---|---|---|
| P0003 | User access level | 1 | Set to 3 to expose all CDS index editors |
| P0182 | Number of command data sets (CDS) | 1 | Extend to enable CDS1..CDS3 |
| P0810 | Command data set selection (CDS bit 0) | 0 | BI source for CDS0/CDS1 switch |
| P0820 | Drive data set selection (DDS bit 0) | 0 | Often confused with P0810 but selects DDS, not CDS |
| P0971 | Save parameter set in non-volatile memory | 0 | Set to 1 to RAM→ROM after editing |
| r0050 | Active command data set (readback) | - | 0..3 = active CDS |
| r0051 | Active drive data set (readback) | - | 0..3 = active DDS |
| r0810 | CDS selection status word | - | Diagnostic; reveals BICO source state |
Field-Proven Tips
- Restore IOP focus: After maintenance work, return the IOP default CDS to 0 by selecting "Do not change data set" from the same menu, then re-selecting CDS0 explicitly.
-
DDS vs CDS confusion: CDS contains command-side parameters (setpoints, ramps, control sources). DDS contains drive-side parameters (motor data, encoder, current limits). They are switched with different parameters (
P0810vsP0820) and read back viar0050vsr0051. -
PROFIBUS bit mapping on CU240E-2 DP: The default PROFIBUS control word mapping for CDS selection uses bit 15 (CDS bit 0). When the PLC toggles bit 15, the drive switches CDS automatically. Confirm via
r0050on the IOP. - STARTER/Startdrive contrast: STARTER and Startdrive show every CDS index in a single editable row (no manual index switch), which is why many engineers believe CDS1 "just works" on the PC tool but appears locked on the IOP. Both tools are writing the same indexed parameters; the IOP just requires explicit index selection.
- IOP-2 compatibility: IOP-2 (touch screen) uses the same menu path but exposes "Command data set" as a tile in Options → Parameter settings → Default data set. Touch navigation replaces wheel scrolling.
FAQ
Why does the IOP only show CDS0 when I open a parameter like P2106?
The IOP always opens the indexed parameter on the CDS that is currently active in the drive (read from r0050), or on the CDS you selected as "Default data set" in the Options menu. If neither has been changed, the drive is on CDS0 and only the .00 index is shown. Use MENU → Options → Parameter settings → Default data set → Command data set → CDS1 to switch the editing focus.
Do I have to set P0810 = 1 before editing CDS1 on the IOP?
No. P0810 = 1 makes the drive run on CDS1. To merely edit CDS1 parameters while the drive runs on CDS0, use the Options → Default data set menu to point the IOP at CDS1 without touching P0810. This is the method documented in Siemens KB 106551863.
How can I enable CDS1 if it is not available at all?
Set parameter P0182 to 2 (or higher, up to 4) and power-cycle the drive. P0182 defines the number of configured CDS. After the power-cycle, the IOP and STARTER will expose indices .00 and .01 for every CDS-bearing parameter.
What is the difference between CDS and DDS in the G120?
CDS (Command Data Set, switched via P0810, readback r0050) carries command-side parameters such as setpoints, ramp times, and control word sources. DDS (Drive Data Set, switched via P0820, readback r0051) carries drive-side parameters such as motor equivalent circuit data, encoder configuration, and current limits. A typical Manual/Automatic application changes CDS only; switching motor types requires a DDS change.
After editing P2106.01 with the IOP the value disappears on power-cycle. What is wrong?
The value was written only to RAM. Run MENU → Memorize (or write P0971 = 1) to save to non-volatile memory. STARTER and Startdrive perform RAM→ROM automatically on download, which is another reason the PC tool appears "to remember" changes the IOP forgets.