SINAMICS G120C P2051 SinaPara Write Error HEX 14 BICO Encoding

1. Problem Summary

When commissioning a SINAMICS G120C drive in freely configurable telegram mode (P0922 = 999, P2079 = 999), the standard tools such as Startdrive and the SINAMICS IOP allow operators to edit parameter r2050 / P2051 / P2060 and its sub-indices directly through the parameter list. When the same write operation is performed from a SIMATIC controller using the SinaPara function block, the drive rejects the request and the block returns error code 16#14 in swErrorNo.

According to the SINAMICS G120C List Manual, error 0x14 (decimal 20) corresponds to the DPRAM/parameter status "value impermissible / not allowed to write". The operator normally interprets this as an access-rights problem, particularly when:

• The drive is at standstill with no active command.
• STO (Safe Torque Off) is active and r2 = [45] Switching on inhibited.
• Both P0922 and P2079 have been verified at 999 in Startdrive.
• The same value is freely accepted by Startdrive but rejected by SinaPara.

Under all of these conditions the actual cause is not a write-protection state. The real cause is the data type and encoding of the parameter being targeted: P2051, P2050, P2060 and similar free-telegram interconnect parameters are CI/CO connectors (BICO inputs/outputs). They do not accept a numeric setpoint — they require a BICO source descriptor encoded as a 32-bit double word.

2. Root Cause: BICO Connector Encoding Requirements

The SINAMICS G120C stores every BICO interconnection as a 32-bit value with the structure defined in the SINAMICS Function Manual for Drive Functions:

When a Siemens commissioning tool such as Startdrive is used, the user simply picks the parameter from a drop-down list and the tool writes the encoded double word transparently. When the operator uses SinaPara, the sdValue input is a DWORD (REAL/WRONG, must be DWORD) and the engineer is responsible for performing the encoding manually. If a plain numeric value (for example 2129 or 16#00000851) is supplied without the BICO framing, the parameter manager responds with 0x14 because the value violates the CI/CO data type range.

3. Prerequisites for Writing P2051 via SinaPara

Before SinaPara writes can succeed, the following prerequisites must be met. The diagnostic flow is intentionally strict because the 0x14 error masks several different root causes.

1. Firmware / Library level: G120C firmware ≥ V4.7 (recommended V4.7 SP10 or V5.x for current safety/Safety Integrated variants) and the SINAMICS blocks library installed in the SIMATIC project (TIA Portal ≥ V16 or STEP 7 V5.5 + SPx with the matching SINAMICS S7 block set). The SinaPara FB can be found in the library "SINAMICS_SinaPara" under Communication > SINAMICS.
2. PROFIdrive channel: The PLC must have an established acyclic channel. SinaPara uses the DPV1 / PROFIdrive acyclic services (read/write record, indices 0xB02E / 0xB02F). Verify the drive is on the same PROFINET/IO or PROFIBUS-DP network and that the telegram configured in the device matches the one selected on the PLC side (the standard free-telegram "999" in TIA). For PN, check the drive's parameter P0922 reflects "Free telegram configuration with BICO" and P2079 is also 999.
3. Drive state: The drive must be in a state that allows parameter writes. Either OFF, Stop, or Operation with ramp enable is fine. Switching on inhibited (r2 = 45) is permissible for parameter writes. The drive does not need to be in run for the BICO interconnections to be accepted.
4. Access level: Confirm P0003 is ≥ 3 (Expert) if any expert-level parameter is targeted. The P2051 / P2060 connectors are accessible at level 3. With Startdrive logged in as Expert, the same project transfers the elevated rights to SinaPara automatically; if SinaPara is the only tool used, the right must be set either by writing P0003 first or by configuring the user class in the drive.
5. Data type of sdValue: Use a DWORD typed variable or a literal of type WORD/DWORD. Float (REAL) inputs are silently coerced and then rejected with 0x14.

4. The SinaPara Value Encoding Format Explained

The SinaPara FB signature (in the SINAMICS blocks library, FB number and instance depend on the library version; in TIA Portal the block is typically labelled SinaPara [FB30500] or the S7-300/400 compatible variant SinaPara [FB2889]) has the following relevant inputs:

The 32-bit sdValue must be built as follows for a write to a connector parameter:

sdValue := 16#[Source parameter number in HEX]_[Source sub-index encoding]

Two sub-cases for the low word are used in practice:

• Source parameter has no sub-index (most parameters): low word is 16#0000.
  Example: P2129 (Faults/alarms trigger signal) → 16#0851_0000 (2129_dec = 0x0851_hex).
• Source parameter has sub-indices: low word uses the pattern 16#FCii where ii is the destination sub-index of the connector itself, e.g. 16#FC02 for sub-index 2 of P2051 / P2060.

5. Step-by-Step: Writing P2051 Sub-Indices via SinaPara

Assume the application must extend the standard PROFIdrive telegram so that:

• PZD7 (send): Source = P2129 (Faults/alarms trigger signal)
• PZD8 (send): Source = P1006 (Fixed speed setpoint 6)

1. Set the drive into free-telegram mode. Using SinaPara or Startdrive, write 999 to P0922 and 999 to P2079.
2. Define the length of the send and receive words. The default P2051[0..15] array is 16 connectors. The number of valid connectors is controlled by P2079 (length PZD send) and P2078 (length PZD receive). Adjust these before populating sub-indices.
3. Compute the encoded sdValue for PZD7.

   // P2051[6] = source P2129
   siParaNo := 2051;
   siIndex  := 6;
   sdValue  := 16#0851_0000;    // 0x0851 = 2129 dec, P2129 has no sub-index
   sWriteRead := TRUE;
   

4. Compute the encoded sdValue for PZD8.

   // P2051[7] = source P1006
   siParaNo := 2051;
   siIndex  := 7;
   sdValue  := 16#03EE_0000;    // 0x03EE = 1006 dec, P1006 has no sub-index
   sWriteRead := TRUE;
   

5. Trigger the SinaPara call. With the request-edge input sReq pulsed (rising edge), the block issues the DPV1 write record. Wait for sDone or sError.
6. Read back the parameter to verify. Reset sWriteRead := FALSE, keep siParaNo := 2051 and the same siIndex, and re-trigger sReq. The returned sdValue should equal the value just written.

6. Complete Worked Examples

The following four examples cover the most common variants encountered in the field. All examples use the SinaPara FB; a single instance must be used for every call (one request at a time per drive). Multiplex the inputs.

6.1 Write a fault word to PZD7 (send)

// Target: P2051[6] (PZD7 transmit, word) = source P2129
siParaNo   := 2051;
siIndex    := 6;
sdValue    := 16#0851_0000;   // 2129 dec = 0x0851 hex; P2129 has no sub-index
sWriteRead := TRUE;

6.2 Write a fixed setpoint to PZD8 (send)

// Target: P2051[7] (PZD8 transmit, word) = source P1006
siParaNo   := 2051;
siIndex    := 7;
sdValue    := 16#03EE_0000;   // 1006 dec = 0x03EE hex; P1006 has no sub-index
sWriteRead := TRUE;

6.3 Connect ramp-up scaling to PZD3+4 (receive DWord)

// P1138 (CI: ramp-fn generator ramp-up time scaling) must be
// fed by P2060[2] which is the PROFIdrive PZD3+4 receive DWord.
// In this case we WRITE TO P1138 (the CI) and the value is the
// BICO descriptor pointing at P2060 sub-index 2.
siParaNo   := 1138;
siIndex    := 0;              // P1138 itself has no sub-index
sdValue    := 16#080C_FC02;   // 0x080C = 2060 dec; FC02 selects sub-index 2 of P2060
sWriteRead := TRUE;

6.4 Receive a 16-bit word to a control word (PZD3 receive word)

// If the source is a 16-bit connector (e.g. P2050, the PZD receive word
// index 2), write directly to the parameter that consumes the connector.
// P2050[2] is the connector for PZD3 receive (word); a parameter that needs
// a 16-bit source uses the descriptor 0x0802_FC02.
siParaNo   := 2050;           // Example: writing to connector input 2050
siIndex    := 2;
sdValue    := 16#0802_FC02;   // 0x0802 = 2050 dec; FC02 selects sub-index 2
sWriteRead := TRUE;

7. SinaPara FB Interface Reference

The SinaPara block exists in two main variants in the Siemens libraries:

Inputs and outputs common to both variants:

Important behavioural notes:

• Only one active request per FB instance. Multiplex the inputs in a sequencer or instantiate one FB per logical parameter stream.
• The FB does not retry on transient acyclic errors. Implement your own retry loop with back-off if a "PROFIdrive drive busy" (0x0E) error appears.
• The FB silently clamps the parameter number to the valid SINAMICS range (0-65535) and the index to 0-255. Out-of-range values are rejected with 0x14 (value impermissible).

8. Error Code Reference

The SinaPara swErrorNo follows the DPV1 parameter request error codes. The most common values are listed below; for the complete list refer to the SINAMICS S120 / G120 Parameter Manual.

9. Verification Procedure

After each batch of BICO writes, verify the interconnections with the following checklist:

1. Read-back check. Use SinaPara to read the same siParaNo / siIndex with sWriteRead := FALSE. The returned sdValue must equal what was written. If it returns 0, the BICO was not accepted (sometimes the drive silently zeros the connector on error; the read-back reveals it).
2. Inspect r2050 / r2051 / r2060 contents in Startdrive. The parameter list shows the resolved source connectors in symbolic form (e.g. "P2129"). They should match the intended sources.
3. Check the I&M / device trace. If the application uses SINAMICS Trace, capture the I/O words (r2050[0..15] for received PZDs, r2051[0..15] for transmitted PZDs) and confirm the values flow as expected.
4. Cycle the drive. A RAM → ROM save (P0971 = 1) makes the connections non-volatile. Power-cycle the drive; verify the connections persist (re-read r2051 / r2050 after power-up).
5. Run a reference speed test. Bring the drive to operating state, apply a small fixed setpoint, and verify the transmitted PZD7/PZD8 words cycle through their expected values.

10. Troubleshooting Matrix

11. Field-Proven Caveats

• The 16#FC prefix in the low word is not a magic value you can omit for indexed sources. The parameter manager uses the bits in the low word to determine if the source is a connector, a parameter without sub-index, or a text reference. Stripping the FC makes the value look like a parameter with no sub-index, which the parameter manager rejects when the destination is itself indexed.
• Do not confuse P2050 (PZD receive word) and P2060 (PZD receive double word). Sub-index 2 of P2050 is PZD3 (16-bit). Sub-index 2 of P2060 is PZD3+4 (32-bit, packed). Using the wrong connector type in sdValue leads to 0x14 on subsequent writes when the encoder telegram is rebuilt.
• Always re-read after writing; do not assume the write succeeded. The acyclic channel silently drops malformed requests on some firmware versions and the FB reports sDone = TRUE with an empty sdValue.
• The G120C variants 6SL3210-1PE (PROFINET) and 6SL3210-1NE (PROFIBUS) both use the same BICO encoding. The same sdValue works on either interface.
• For safety-related drive variants (G120C with CU250S-2 safety firmware), safety parameters (r/r9799, r/r9720) are read-only from the acyclic channel; attempting a write returns 0x04. SinaPara should not be used to configure the safety channel.

12. FAQ