Siemens 6RA7085-6DV62-0 Replacement for SIMOREG DC-MASTER

Product Overview

Siemens 6RA7085-6DV62-0 Replacement for SIMOREG DC-MASTER: Smooth Transition & Legacy System Compatibility

The Siemens 6RA7085-6DV62-0 is a high-power DC drive converter from the SIMOREG DC-MASTER series, rated at 850 A armature current and designed for demanding industrial DC motor control applications including rolling mills, extruders, winding machines, hoists, and large-scale pump and fan drives. As this model reaches end-of-production lifecycle milestones, plant engineers and procurement teams are increasingly seeking verified replacement units, upgrade pathways, and retrofit-compatible alternatives that preserve existing wiring infrastructure, motor parameters, and control architecture.

TOPNLMS maintains in-stock inventory of the 6RA7085-6DV62-0 and offers direct ship from our Xiamen warehouse, enabling rapid deployment to minimize unplanned downtime. Each unit undergoes pre-shipment functional verification and ships with a 12-month warranty.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful migration from an aging DC drive system to the 6RA7085-6DV62-0 rarely involves the converter alone. In practice, field engineers must evaluate the entire drive train and control cabinet ecosystem to ensure a smooth cutover with minimal rewiring and zero program loss.

When replacing older SIMOREG K 6RA2218 or 6RA2428 units, the armature and field terminal assignments on the 6RA70 platform differ slightly, requiring careful cross-referencing of the X1 and X2 terminal blocks. The integrated field supply on the 6RA7085-6DV62-0 eliminates the need for a standalone field controller board that was common in earlier cabinet designs, freeing up DIN rail space for other components.

For sites running PROFIBUS DP networks, the CBP2 communication board (order reference 6SX7010-0FF00) slots directly into the option slot of the 6RA70 chassis, enabling seamless integration with existing S7-300 or S7-400 PLC racks without any gateway hardware. Sites still operating on legacy serial protocols may require a USS/PROFIBUS converter module as an interim bridge during phased migration.

Encoder feedback is a critical consideration. If the existing motor uses a DC tachogenerator, the SBP pulse encoder board can be configured to accept analog tach signals, or the motor can be retrofitted with an HTL incremental encoder for improved speed regulation accuracy. For high-precision tension control applications such as winding and unwinding lines, upgrading to a digital encoder simultaneously with the drive replacement yields measurable improvements in web tension stability.

On the control side, parameter migration from an older SIMOREG unit to the 6RA70 platform is performed using Siemens DriveMonitor software. Engineers should back up all existing P-parameters before decommissioning the old unit. Key parameters including ramp times, current limits, speed controller gains, and field weakening curves must be re-entered and verified under no-load and full-load conditions during commissioning.

Cabinet-level integration typically also involves reviewing the 6EP1 series SITOP power supply feeding the 24 VDC control circuit, the 3RT contactor on the AC input side, and any existing 6SL3 line filter or line reactor (also referred to as a commutating reactor or line choke) that conditions the supply to the converter. These components should be inspected and replaced if they show signs of thermal aging, as they directly affect converter reliability and harmonic compliance.

For multi-drive systems where several DC converters share a common DC bus or are coordinated via a master-follower topology, the T400 technology board or peer-to-peer fiber-optic link between 6RA70 units enables synchronized speed and torque control without additional PLC intervention. This is particularly relevant in tandem mill and draw bench applications.

Finally, HMI integration should be reviewed. Many legacy systems use a OP7 or OP17 operator panel connected via MPI. Migrating to a modern KTP700 Basic HMI with PROFIBUS or PROFINET connectivity provides a significant improvement in diagnostics visibility and alarm management, and is straightforward to configure using TIA Portal.

Retrofit Guidance FAQ

Q: Can I reuse the existing armature and field wiring from my old SIMOREG unit?
A: In most cases, yes. The 6RA7085-6DV62-0 uses standard terminal designations for armature (1U1/1V1) and field (E1/E2). Verify cable cross-section ratings against the 850 A armature current. Field wiring is typically reusable as the integrated field supply accepts standard field coil impedances.

Q: Will my existing PROFIBUS DP network work without reconfiguration?
A: With the CBP2 board installed, the 6RA7085-6DV62-0 appears on the PROFIBUS network as a standard DP slave. You will need to import the GSD file into your PLC engineering tool (STEP 7 or TIA Portal) and reassign the I/O addresses. Existing PLC logic driving speed setpoints and enable signals typically requires only minor address remapping.

Q: How do I handle the physical size difference if the old unit was a larger chassis?
A: The 6RA70 frame H is a compact booksize design. If replacing a larger legacy chassis, a mounting adapter plate and extended cable looms may be required. TOPNLMS can advise on mechanical adaptation based on your cabinet drawings.

Q: What is the commissioning sequence after installation?
A: Power up the 24 VDC control supply first, verify no fault codes on the PMU panel, then perform motor data identification (P107 = 1) with the motor uncoupled from the load. After auto-identification, restore ramp and controller parameters, then perform a loaded test run at 10%, 50%, and 100% speed setpoints before returning to production.

Q: Can this unit replace a 6RA7085 variant with a different suffix?
A: The suffix encodes the field supply voltage and option configuration. The -6DV62-0 suffix indicates a specific field voltage range and option slot configuration. Cross-referencing with the Siemens 6RA70 catalog is recommended before substituting a different suffix variant.

Warranty Assurance

Every 6RA7085-6DV62-0 unit shipped by TOPNLMS is covered by a 12-month warranty from the date of shipment. Prior to dispatch, each converter undergoes a multi-point functional check including power-on self-test, control board communication verification, and visual inspection of bus bars, capacitor banks, and thyristor assemblies.

In the event of a warranty claim, TOPNLMS provides a replacement unit or repair service with a target response time of 3 business days from claim receipt. Customers are required to return the defective unit in its original packaging. Warranty coverage applies to functional and manufacturing defects and does not cover damage resulting from incorrect installation, overvoltage events, or unauthorized modification.

For procurement teams requiring documentation, TOPNLMS can provide a test report, packing list, and commercial invoice with HS code declaration upon request. Expedited shipping via DHL Express or FedEx International Priority is available for urgent replacement scenarios.

Contact our technical sales team to confirm stock availability, request a quotation, or discuss retrofit engineering support before placing your order.