SINAMICS G120C Free Function Blocks: Firmware, Parameter Access, and Configuration

The SINAMICS G120C supports onboard logical, timing, and arithmetic operations through its Free Function Blocks (FFB) firmware feature. Unlike the SINAMICS S120, G130/G150, or G150P platforms, the G120C does not support Drive Control Chart (DCC); instead, all closed-loop, sequencing, and Boolean logic functions are executed by FFBs that are part of the standard firmware and parameter space. This article resolves the most common field complaint — "I cannot find the function blocks, urgently need a timer" — by walking through firmware requirements, part-number identification, parameter mapping, expert-list configuration, and runtime diagnostics for the G120C PN (6SL3210-1KE11-8UF2) and adjacent variants.

1. Problem Statement

An integrator configures a SINAMICS G120C PN (article number 6SL3210-1KE11-8UF2) and attempts to use an on-delay timer or a Boolean network inside the drive. The expected parameters (for example p20138, the run-time group selector, or the AND/OR block instance parameters) are not visible in the STARTER/Startdrive parameter list, and the FFB editor is not present. The drive ships with firmware V4.7.06.04 and STARTER was installed without the optional components.

The user's underlying need is to deploy simple on-board automation — pump staging, valve sequencing, fault latching, watchdog timing, or analog conditioning — without adding a SIMATIC PLC to the line.

2. Affected Products and Part-Number Decoding

The article number 6SL3210-1KE11-8UF2 decodes as follows:

The "UF2" suffix confirms a PROFINET interface and the V4.7 firmware generation. FFBs were introduced in this generation but only became fully functional with hotfix V4.7 SP6. Earlier V4.7.x builds (V4.7.0 through V4.7.5) expose only a partial FFB set, and V4.7.6 (SP6) is the first release in which the full block catalog — including timers, RSR/DFR flip-flops, and the integrator — is present.

3. Reading the Internal Firmware Version

The G120C stores the firmware version as an integer in parameter r0018. Decode the value as follows:

Procedure: with the drive online in STARTER or Startdrive, navigate to Online → Accessible nodes, connect to the G120C, expand Drive unit → CU → Parameter list, and inspect r0018. The hex/binary representation corresponds to a Siemens internal version map; the decoder table above covers the V4.7 branch. If the value is below 4 706 000, FFB availability is limited or absent and the unit must be flashed to V4.7 SP6 or later.

4. Firmware Update Path to V4.7 SP6

1. Download the latest SINAMICS G120C V4.7 SP6 firmware ZIP from the Siemens support portal entry 109482659.
2. Extract the archive to a known folder. Inside, locate the file SINAMICS_G120C_04700600.bin (or higher HF build).
3. Connect the G120C PN to the engineering PG via PROFINET or the mini-USB service port (use a SIMATIC USB cable, e.g. 6SL3555-0PA00-0AA0, with the drive powered).
4. In STARTER: Online → Accessible nodes → select drive → Right-click → Target system → Load firmware to drive → confirm the After loading, perform RAM-to-ROM box.
5. Wait for automatic restart. Verify r0018 ≥ 4 706 000.
6. Cycle drive power to flush any cached FFB run-time groups.

5. Free Function Block Catalog

The full FFB catalog is documented in the Siemens FAQ 85168215 and the attached FFB PDF. Categories available on the G120C with V4.7 SP6:

Each block is parameter-based: enabling a block, wiring its inputs and outputs, and configuring the time constants are all done by writing to parameters. There is no graphical editor, no compiled code, and no download to a separate FFB runtime — the firmware interpreter reads the parameter set every cycle.

6. Parameter Numbering and Run-Time Groups

FFB parameters live in the high range, typically p20100 through p20299. The structure follows this convention:

• Block instance parameters — e.g. p20138 identifies a specific block instance (input configuration) and a matching output parameter in r20138.
• Block enable — most blocks are enabled by writing 1 to a dedicated run-time group bit.
• Run-time groups — parameters p20116 to p20119 assign each block to one of four available groups. Each group runs at a configurable sampling time (p20115 field); the firmware executes group 0 at the highest rate (current-controller / 125 µs on most G120C variants) and groups 1–3 at lower rates suitable for sequencing and slow logic.
• Time-base parameter — p20115 sets the base sampling interval for the run-time groups; verify the value is consistent with the expected timer resolution.

7. STARTER Configuration Procedure

STARTER is the older commissioning tool (TSAP S7ONLINE) and is appropriate for all V4.7 firmware branches. STARTER has no dedicated FFB GUI; configuration is performed via the expert parameter list.

1. Open STARTER and connect to the G120C. Bring the project online.
2. Right-click the drive unit → Expert list.
3. Change the filter to All parameters and switch the view to Expert (top toolbar). The expert list shows the full V4.7 SP6 parameter space.
4. Navigate to the FFB block you want to wire (for example the on-delay timer block, parameter range p20130–p20149 depending on block).
5. Configure input connectors by writing the parameter number of the source signal into the block's input fields. Connectors are signalled by their parameter number; the firmware resolves cross-references at runtime.
6. Set the time constant parameter (e.g. p20148 for the timer) in milliseconds.
7. Assign the block to a run-time group via p20116 to p20119; for sequencing, group 1 (4 ms typical) is a good compromise.
8. Save RAM to ROM on the drive and copy the parameters back to the PG (Load to PG/PC) so the offline project matches the drive.

8. Startdrive Configuration Procedure

Startdrive (TIA Portal add-in) is the modern commissioning tool and supports FFB configuration from V15 onward. It still resolves FFBs to the underlying parameter set, but presents them in a flatter hierarchy.

1. Open the TIA Portal project, expand the G120C device, and go online.
2. Open Parameters → All parameters and set the filter to Show all.
3. Group filters by Function; the Free function blocks group shows the available blocks.
4. Right-click the desired block → Configure. Startdrive writes the correct input connector, run-time group, and timing parameters for you.
5. For visualization, use Watch table to read the corresponding r… result parameter in real time.

9. Worked Example: On-Delay Timer Wiring

The most common FFB ask is "I urgently need a timer". The on-delay block (PDE) is enabled as follows. Connector numbers and parameter indices below follow the V4.7 SP6 FFB manual; verify each against the live r0018 version:

1. Pick a Boolean source (for example, drive state Run from r0899.2). This is the trigger input.
2. Locate the PDE block's input connector parameter (e.g. p20140[0]) and write the parameter number of the source: 899.2 means 0899.2; the firmware treats this as the digital state of bit 2 of r0899.
3. Set the time constant in p20148[0] in milliseconds. For a 5-second delay, enter 5000.
4. Assign the run-time group via p20116[0]; for sequencer use, group 1 is recommended.
5. Wire the output connector (r20140[0]) to the desired target, for example the run enable of a free technology function or a status word bit exposed over PROFINET.
6. Set the run-time group time base via p20115[0] for group 0 and analogous indices for groups 1–3.
7. Save to ROM and verify by monitoring the output bit in Startdrive's Signal monitor or by writing the output to a free PZD word on PROFINET.

10. Diagnostic and Runtime Parameters

Each FFB instance has a matching result parameter in the r range. When troubleshooting, watch:

• r0018 — internal firmware version (decode per Section 3).
• r20138 / analogous r… outputs — the live Boolean or analog result of the wired block.
• r20115 and run-time group counters — indicate that the firmware is actually executing the block group at the configured interval.
• r0947 / r2124 — fault and alarm codes. A mis-wired FFB may raise F08501 (signal source invalid) or simply not produce output without alarming.
• r9798 — safety of the parameter checksum; an FFB parameter change forces a new checksum on the next save.

11. Verification Procedure

1. Confirm firmware: r0018 ≥ 4 706 000.
2. Open the expert parameter list and confirm presence of p20138 (or the specific block parameter for the desired function). If absent, the project is offline or the parameter filter is hiding expert parameters.
3. Save parameter set to the PG, save to ROM on the drive, and power-cycle the drive.
4. Force the input connector (e.g. via a digital input or a free PZD bit) and observe the output parameter in Startdrive's Signal monitor.
5. Toggle the time constant and run-time group time base to confirm dynamic response matches the design intent.
6. Record the project archive with the matching firmware version. Siemens support explicitly asks for project archive + firmware version + r0018 when escalating FFB tickets.

12. Troubleshooting Matrix

13. Field-Proven Caveats

• No DCC, no CFC, no licensing. FFBs are part of the standard firmware. The CFC option referenced in the source thread relates to SIMATIC PLC CFC, not to the drive — do not install CFC to "get" the FFBs.
• STARTER and Startdrive behave differently. In STARTER the FFB parameters are reached via the expert list only; in Startdrive a guided wizard is available from V15.1 onwards. Engineers familiar with DCC will initially look for a block diagram — there is none for FFB; configuration is purely parametric.
• Run-time group time base. For pump staging or sequencing tasks, set group 1 to 4 ms; group 2 to 16 ms. Faster groups consume CPU and may conflict with closed-loop performance; slower groups may miss fast triggers.
• ROM save required. FFB parameter changes are volatile until a RAM-to-ROM save is executed and the drive power is cycled.
• SINAMICS G120X note. The G120X supports the same FFB concept and exposes them through the Smart Access Module (SAM) web server — useful for field service tablets. The G120C lacks the SAM web interface, so use STARTER/Startdrive.