Migrating SIMOREG DC-MASTER Block SIMO_DCM (FB623) to SIMATIC PCS 7 V9.0

Legacy SIMOREG DC-MASTER control blocks such as SIMO_DCM (FB623) cannot be directly extracted from a PCS 7 V7.2 library and loaded into PCS 7 V9.0 without migration packages. FB623 relies on legacy driver architectures (CH_AI, MOD_D1) and 32-bit WinCC faceplates that are fundamentally incompatible with PCS 7 V9.0 module driver generators and 64-bit operating systems. To migrate, engineers must deploy the official Siemens Drive ES PCS 7 Migration Library or upgrade to Drive ES PCS 7 APL blocks communicating via standard PROFIBUS telegrams. Verifying exact library versions in the Siemens Compatibility Tool ensures seamless controller and operator interface integration.

SIMO_DCM (FB623) Architectural Background

The function block SIMO_DCM (FB623) was developed for the SIMOREG DC-MASTER 6RA70 drive converter family, originally distributed within the legacy Drive ES PCS 7 or SIMOCODE/Drive integration libraries. It provides cyclic control word transmission, speed setpoint scaling, armature current monitoring, and drive fault handling over PROFIBUS-DP.

In PCS 7 V7.2, FB623 operated in conjunction with the classic PCS 7 Standard Library and classic module driver blocks (MOD_D1, CH_DI, CH_AI). In modern PCS 7 V9.0 environments, these classic driver layers have been entirely superseded by the Advanced Process Library (APL) and modern driver generator engines.

Compatibility Barriers Between PCS 7 V7.2 and V9.0

Directly importing FB623 into PCS 7 V9.0 causes severe architectural failures:

Subsystem / LayerPCS 7 V7.2 ImplementationPCS 7 V9.0 ArchitectureImpact of Direct Block CopyDriver GenerationClassic Generate Module Drivers (V7 driver rules)APL Driver Generator (DiagAct, Pcs7DiIn)Compiler error: module driver interconnection fails; diagnostic structure mismatch.OS FaceplatesClassic WinCC V7.0 32-bit @PG_SIMO_DCM.pdlModern APL Styleguide faceplates, WinCC V7.4 SP1Faceplates fail to open; missing ODK script DLLs; graphic corruption.CPU Operating SystemS7-400 V5.x firmware architectureAS 410-5H firmware V8.2 / modern S7-400HSFC type incompatibilities and startup organization block (OB100) structure faults.

Migration Strategies and Upgrade Paths

Engineers executing plant modernizations from PCS 7 V7.2 to V9.0 have two verified upgrade paths:

Path A: Deploy Drive ES PCS 7 Migration Library (Conservative)

Procure the Drive ES PCS 7 Migration Library V9.0 (compatible with classic block interfaces).
Install the migration library on the PCS 7 V9.0 Engineering Station.
In the CFC Chart Editor, execute Options -> Block Types... -> clean update from the new migration library.
Compile CFC and OS: the migration library contains updated OS faceplates and module driver rules compatible with PCS 7 V9.0.

Path B: Modernize to Drive ES PCS 7 APL / Standard APL (Recommended)

Replace SIMO_DCM instances with modern APL drive blocks, such as MotSpdCL (FB1854) paired with FbDrive (FB1881).
Maintain standard PROFIBUS-DP cyclic communication (e.g., Telegram 1 or Telegram 20) with the SIMOREG 6RA70 or SINAMICS DCM (6RA80).
This fully integrates the drive into the APL ergonomics, alarm management, and maintenance station diagnostics.

Verification

To verify successful drive integration in PCS 7 V9.0:

Open HW Config: verify the SIMOREG DC-MASTER PROFIBUS slave configuration displays healthy status.
In CFC, run Options -> Check Consistency -> verify zero block header or driver generation errors.
Compile CFC with Generate module drivers enabled: confirm driver blocks compile cleanly without warnings.
In WinCC OS Runtime, click the drive block icon: confirm the faceplate opens displaying valid speed feedback and control buttons.
Issue Start/Stop and speed setpoint commands: confirm bidirectional communication with the physical drive converter.

Limitations and Operational Precautions

Operational boundaries when modernizing legacy drives:

SIMOREG 6RA70 Lifecycle: The SIMOREG 6RA70 drive series is in phased-out lifecycle status. For major modernizations, evaluate replacing hardware with modern SINAMICS DCM (6RA80) converters.
Module Driver Incompatibility: Never mix classic PCS 7 Standard Library driver blocks with APL driver blocks within the same automation station rack.
Commercial Procurement: Drive ES PCS 7 libraries require dedicated software licenses per engineering station. Final license requirements and MLFBs must be verified against authorized Siemens distribution quotations.

Engineer FAQ

Can I simply copy FB623 from a V7.2 project library into a V9.0 master data library?

No. The compiled block code expects obsolete system structures and lacks the diagnostic interfaces required by the PCS 7 V9.0 module driver generator, leading to compile crashes.