Configuring Masterdrive MC on PROFIBUS-DP with S7-300 CPU

1. Overview

The SIMOVERT MASTERDRIVES MC (Motion Control) family is a legacy Siemens three-phase AC drive platform that still appears in long-life industrial plants, paper machines, hoists, and crane retrofits. Integrating a MASTERDRIVES MC unit — for example MLFB 6SE7013-0EP50 — into a SIMATIC S7-300 station centered on a CPU 313C-2DP requires the correct PROFIBUS-DP slave description (GSD), a properly slotted communication board (CBP / CBP2), the right PPO telegram type, and consistent-data handling via SFC14 and SFC15. This reference covers all four layers using SIMATIC Manager V5.4 SP5 (or compatible) and the MASTERDRIVES Vector Control compendium, software release V3.32 and above.

The procedure applies to the MC compact and chassis variants. For software V3.32 or newer, the operating instructions are available in the Siemens IA/DT support portal as the "SIMOVERT MASTERDRIVES Vector Control" compendium PDF, which contains Section 8.2.3 describing the parameter-processing mechanism over PROFIBUS. The latest published revision can be downloaded from Siemens support entry 23658440 — SIMOVERT MASTERDRIVES Vector Control Operating Instructions (V3.32).

2. System Components and MLFB References

Match every component to its catalog number before commissioning. The items below are the minimum hardware/software set used in a working configuration.

Confirm the CBP/CBP2 sticker inside the MASTERDRIVES door before continuing. The GSD for a CBP2 differs from the GSD for a CBP; mixing them produces a "Slave not found" or "Configuration error" diagnostic.

3. Prerequisites

Install the following before opening HW Config:

1. SIMATIC Manager V5.4 SP5 with the S7-300 / PROFIBUS option package.
2. The latest Masterdrive HSP (Hardware Support Package) — referenced from Siemens entry 23183356 — HSPs for SIMATIC S7.
3. The Masterdrive GSD file matching the CBP board (CBP2 most common for V3.x firmware). GSD repository is referenced from Siemens entry 113204 — GSD files for SIMOVERT MASTERDRIVES.
4. The MASTERDRIVES Vector Control compendium PDF for parameter indexing. Section 8.2.3 ("Mechanisms for processing parameters via PROFIBUS") is the controlling specification; it is mirrored in Siemens entry 23660019 — Connection of Masterdrives to Profibus-DP.
5. DriveMonitor or STARTER commissioning tool to read/write the same parameters from a PC for cross-verification.

4. Installing the GSD File and HSP in SIMATIC Manager

1. Close all SIMATIC Manager windows.
2. Launch Options → Install GSD File and select the correct .GSD (and accompanying .BNF / bitmap files). STEP 7 copies the GSD into \Step7\S7DATA\GSD.
3. Launch Options → Install HW Updates and import the Masterdrive HSP. The catalog entry "SIMOVERT" appears under PROFIBUS-DP → Drives → SIMOVERT.
4. Restart HW Config so the new catalog entries load.

If the GSD is missing or the board does not match, the slave will accept the slot configuration but raise diagnostic byte 0x0B (extended diagnostic) with identifier-byte 0x83 ("Slave requires a different configuration"). Always confirm the catalog entry reads "CBP2" (or "CBP") for the slot used.

5. Hardware Configuration in HW Config

1. Insert a SIMATIC 300 station and add the CPU 313C-2DP on the rail.
2. Open the CPU properties, switch to the DP tab, and set Operating Mode = DP-Master. Choose a bus address (default 2) and a transmission rate of 1.5 Mbit/s for cable lengths up to 200 m, or 12 Mbit/s only for short, well-terminated segments.
3. Drag the Masterdrive slave from the catalog to the DP master system. Assign the slave's PROFIBUS address (default 3, configured on the CBP2 DIP switches or via P918).
4. Open the slave's DP-Slave Properties dialog and select the slot. If the HSP catalog entry is used, the PPO types appear directly. If the imported GSD is used, the GSD-driven dialog shows the same PPO slots; align them manually.

For drive commissioning that requires reading fault memory (r947) and writing ramp times (P460 / P461) while running, PPO1 is the smallest viable option and is often chosen to keep the cycle budget low. PPO5 is the largest and is required if you need to read or write more than two process data words in each direction (e.g., torque, speed, current, status).

6. PPO Type Selection and Telegram Structure

Each PPO telegram is divided into two zones: the parameter identification zone (PKW) and the process data zone (PZD). The PKW zone is optional; PPO2 and PPO3 omit it.

6.1 PZD — Process Data Zone

PZD is the cyclic data exchanged every PROFIBUS-DP cycle. The first output PZD is the control word (STW, parameter r550); the first input PZD is the status word (ZSW, parameter r551). Subsequent PZDs are user-definable setpoints and actuals configured via parameters P554.1 … P591.1 (control word connectors) and P694.1 … P740.1 (status word connectors).

6.2 PKW — Parameter Identification Zone

PKW is a non-cyclic, acyclic-style channel presented inside the cyclic frame. It must be transferred as a single 8-byte (4-word) block; partial writes are rejected. The block layout is shown below.

7. PKW Parameter Access Mechanism

The MASTERDRIVES parameter processing on PROFIBUS follows the mechanism defined in compendium Section 8.2.3. A request and its response share the same PKE.IND identifier; the drive sets AK = 1 on success and returns the value in PWE1/PWE2.

For S7-300 firmware, parameter 947 is the active fault buffer entry. To read the most recent fault:

1. Set PKE = 0x13B3 → AK = 1 (read), PNU = 0x3B3 (947).
2. Set IND = 0x0000 → index 0.
3. Set PWE1 = 0 and PWE2 = 0.
4. Transfer the 4 words atomically using SFC14 / SFC15.
5. Poll until AK in the response equals 1; then concatenate PWE1 << 16 | PWE2 to obtain the fault code.

Fault codes reported by r947 are documented in compendium Section 7. Examples: F001 = overcurrent, F002 = overvoltage, F003 = power module overtemperature, F005 = I²t overload, F006 = chopper overload, F008 = loss of field, F011 = user fault 1, F012 = user fault 2, F030 = loss of commutation, F031 = speed controller output limited, F033 = setpoint/actual deviation, F035 = overspeed, F041 = encoder fault, F042 = tachometer fault, F051 = parameter access error via PKW. The decoding map is a moving target across firmware revisions, so always cross-check against the V3.32 compendium table.

8. SFC14 and SFC15 Programming for Consistent Data

PKW and PZD words spanning more than 4 bytes require consistent read/write — a normal L PIW / T PQW sequence does not guarantee atomicity and is rejected by the CBP. Use SFC14 DPRD_DAT for reading and SFC15 DPWR_DAT for writing.

8.1 SFC14 — Read Consistent Data from DP Slave

8.2 SFC15 — Write Consistent Data to DP Slave

8.3 SCL/ST Sample — Read PPO1 Input Image

// Read full 10-word (20-byte) PPO1 input image from slave at I-start 256
DATA_BLOCK DB_PPO1_IN
   STRUCT
      PKE  : WORD;   // word 0 (input view)
      IND  : WORD;   // word 1
      PWE1 : WORD;   // word 2
      PWE2 : WORD;   // word 3
      PZD1 : WORD;   // ZSW (status word)
      PZD2 : WORD;   // actual value 1 (e.g., r550 routed to ZSW, r002 speed)
   END_STRUCT
END_DATA_BLOCK

CALL  SFC14
   LADDR  := W#16#100   // base I/O address from HW Config (decimal 256)
   RET_VAL := MW100     // 0 = success
   RECORD := P#DB_PPO1_IN.DBX0.0 BYTE 20   // 10 words = 20 bytes

8.4 SCL/ST Sample — Write PPO1 Output Image

DATA_BLOCK DB_PPO1_OUT
   STRUCT
      PKE  : WORD := W#16#13B3;   // AK=1 read, PNU=947
      IND  : WORD := W#16#0;      // index 0
      PWE1 : WORD := W#16#0;
      PWE2 : WORD := W#16#0;
      PZD1 : WORD := W#16#47E;   // STW: enable + setpoint enable
      PZD2 : WORD := W#16#0;     // setpoint 0 for test
   END_STRUCT
END_DATA_BLOCK

CALL  SFC15
   LADDR  := W#16#0     // base Q address (example: 0)
   RECORD := P#DB_PPO1_OUT.DBX0.0 BYTE 20
   RET_VAL := MW102

9. Reading Fault Values from r947

Parameter r947 is a 32-bit status word that holds the currently active fault code (or the most recent fault if the drive is no longer in a fault state). Reading it via PKW requires a 32-bit value, so PWE1/PWE2 are used as the high/low half.

9.1 Request Frame (PKW, AK = 1, PNU = 947)

9.2 Response Frame (on Success)

Fault code = (PWE1 << 16) | PWE2. For 16-bit faults (the common case) the value fits entirely in PWE2; PWE1 = 0. Acknowledge with control word bit 7 in the next PZD cycle; the drive clears the fault and the AK = 1 response reflects the cleared state.

10. Writing Ramp Times (P460 / P461)

Ramp-up time is P460; ramp-down time is P461. Both are 16-bit floating-point values stored in PKW as 32-bit IEEE-754 (a Mantissa-Byte / Exponent-Byte pair is also accepted by older firmware). To write a 2.0-second ramp:

10.1 Write Request for P460 = 2.0 s

10.2 PKW Write — Universal Module 6-Word Variant

If you selected a "Universal module" with 6 PZD words (no PKW zone) instead of a true PPO1/PPO5, you cannot write P460 / P461 over PROFIBUS. Either switch the slot to PPO1 / PPO4 / PPO5 in HW Config, or write the ramp times from the AOP (Advanced Operator Panel) keypad, or use DriveMonitor over the RS232 service port. With PPO1/4/5 selected, ramp times can be written while the drive is in run state — a common practice for test stands.

11. Verification and Commissioning Checklist

1. In HW Config, the slave shows a green check icon and the diagnostic buffer of the CPU 313C-2DP is free of "Slave failure" / "Configuration error" events.
2. With PPO1/4/5 selected, the input PZD[1] (status word) reads 0x4B31 in 0_0 state, transitioning to 0x4B37 on run, 0x0B31 on enable, and 0x0B38 on fault (per compendium Section 6.3).
3. Send a PKW read of P000; the response should be the drive's 16-bit identifier (e.g., 1101 for MC compact, software V3.32).
4. Send a PKW read of r947; verify the returned value against the keypad fault history.
5. Write P460 = 1.5 s, P461 = 2.0 s via PKW. Read back via PKW and confirm on the AOP that the values match.
6. Use DriveMonitor or STARTER over RS232 to read the same parameters and confirm PROFIBUS and keypad values agree — this proves the GSD and PPO selection are correct.

12. Troubleshooting Matrix

13. Field-Notes and Edge Cases

• CPB2 vs CBP timing: CBP2 supports 12 Mbit/s; original CBP is limited to 1.5 Mbit/s. Attempting 12 Mbit/s on a CBP-only drive produces DP bus timeouts and SF on the CPU.
• Address switch on CBP2: Some CBP2 boards read the PROFIBUS address from P918 instead of the DIP switch when the address is non-zero. Confirm with the V3.32 compendium Section 4.1.
• Multiple drives on one DP line: Each Masterdrive must have a unique address (3…125). Repeaters are required when cable length exceeds 200 m at 1.5 Mbit/s or when more than 32 slaves are connected.
• Save parameters to EEPROM: PKW writes go to RAM only. Issue a PKW write of P971 = 1 (save) to commit changes to non-volatile memory. Save takes 2–4 seconds; do not power-cycle in this window.
• Software V3.32 vs V4.x: The compendium and GSD match V3.32 and later compact MC drives. V4.x firmware on VC units (Vector Control, not Motion Control) uses a different PKW semantics for some safety-relevant parameters — always cross-reference the FW version against the GSD revision date.

FAQ