Siemens C98043 Series Control Boards

Technical Dossier

Product Details And Specifications

Siemens C98043 Series: Comprehensive Module Range and Technical Overview

The Siemens C98043 series comprises the core control and interface boards used in SIMOREG DC Master and SIMOVERT drive platforms — systems with documented installation bases across petrochemical refineries, nuclear power auxiliary systems, steel rolling mills, and continuous process chemical plants. These boards govern firing pulse generation, current regulation, speed feedback processing, and field excitation control in DC drive cabinets rated from a few kilowatts to multi-megawatt configurations. The C98043 designation covers a family of printed circuit assemblies manufactured to Siemens industrial quality standards, with variants differentiated by function suffix (e.g., -A7001, -A7002, -A7003) and hardware revision level (e.g., -L1, -L2, -L4). Installed units remain in service in facilities where drive replacement is cost-prohibitive, making spare board availability a critical operational requirement.

The Evolution of C98043 Architecture

The C98043 board family was introduced alongside the SIMOREG 6RA24/6RA26 series in the late 1980s and was progressively adapted through the 6RA70 (SIMOREG DC Master) platform into the 2000s. Early revisions (-L1) used through-hole component technology with discrete analog signal conditioning. Subsequent revisions (-L2, -L4) integrated surface-mount components, revised EPROM firmware, and improved EMC filtering on the feedback input circuits. The architecture centers on a microcontroller-based regulation core communicating over an internal parallel bus to I/O interface sub-boards. Compatibility between revision levels is function-specific: in many cases an -L2 board is a direct drop-in for an -L1 position, but firmware version alignment with the drive's main CPU board must be verified. As the 6RA70 platform reached end-of-production, Siemens transitioned customers toward the SINAMICS DCM (6RA80) series, which uses a fundamentally different modular architecture and is not backward-compatible at the board level. C98043 boards are therefore classified as legacy/mature lifecycle components with no current-production equivalent, and sourcing relies entirely on new-old-stock (NOS) and refurbished supply chains.

C98043 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified members of the Siemens C98043 control board family, organized by functional category. Each entry reflects the board's primary role within the SIMOREG/SIMOVERT drive system.

Regulation & Control Boards

• C98043-A7001-L2-4: Main regulation board, current/speed loop control for 6RA70 DC drives
• C98043-A7001-L1-4: Earlier hardware revision of main regulation board, 6RA24/6RA26 compatible
• C98043-A7001-L4-4: Revised regulation board with updated EMC filtering and SMD components
• C98043-A7002-L1-4: Field supply regulation board, controls DC field excitation current
• C98043-A7002-L2-4: Revised field regulation board, improved thermal management
• C98043-A7003-L1-4: Pulse generation board, firing pulse output to thyristor gate circuits
• C98043-A7003-L2-4: Updated pulse generation board, revised gate drive output stage

Interface & I/O Boards

• C98043-A7004-L1-4: Analog I/O interface board, speed reference and feedback signal conditioning
• C98043-A7004-L2-4: Revised analog I/O board with extended input voltage range
• C98043-A7005-L1-4: Digital I/O interface board, binary command and status signal routing
• C98043-A7005-L2-4: Updated digital I/O board, additional optocoupler isolation stages
• C98043-A7006-L1-4: Technology board, extended closed-loop function blocks for winder/unwinder applications

Communication & Fieldbus Boards

• C98043-A7007-L1-4: PROFIBUS-DP communication board for 6RA70 series integration
• C98043-A7008-L1-4: Serial interface board, USS protocol communication adapter
• C98043-A7009-L1-4: Encoder interface board, incremental encoder feedback processing up to 300 kHz

Power Supply Boards

• C98043-A7010-L1-4: Internal SMPS board, generates regulated DC rails for control electronics
• C98043-A7010-L2-4: Revised SMPS board, improved hold-up time and short-circuit protection

Sourcing Hard-to-Find & Obsolete C98043 Parts

Siemens formally discontinued production of C98043 series boards as part of the broader 6RA70 platform end-of-life process. Standard Siemens distribution channels no longer carry these parts as new stock. DriveKNMS maintains a dedicated inventory of C98043 boards sourced through controlled dismantling of decommissioned drive cabinets, verified NOS stock from original equipment manufacturers, and tested refurbished units from industrial surplus. Each unit entering inventory is logged with its hardware revision level and, where recoverable, its firmware version. For facilities operating SIMOREG 6RA70 drives under long-term maintenance contracts, DriveKNMS can provide consignment stock arrangements and advance replacement programs to minimize unplanned downtime. Requests for specific revision levels or quantity requirements should be submitted directly to the procurement team.

Quality Control for the C98043 Range

C98043 boards present specific test challenges due to their mixed analog/digital architecture and dependence on drive-system context for full functional verification. DriveKNMS applies the following test protocol to all C98043 units: (1) Visual inspection for PCB delamination, capacitor bulge, corrosion on edge connectors, and solder joint integrity under 10x magnification. (2) In-circuit component verification of critical analog sections including op-amp networks, voltage reference ICs, and optocoupler isolation barriers. (3) Powered bench test using a SIMOREG 6RA70 test rig with calibrated load, verifying regulation loop response, I/O signal levels, and communication bus activity. (4) Thermal cycling to identify intermittent failures in solder joints and component packages. (5) Final documentation of test results, hardware revision, and any replaced components, issued with each unit. Units that do not pass all stages are either repaired to component level or classified as non-serviceable and removed from inventory.