CUR BOARD C98043-A1680-L1 6SE7090-0XX85-1DA0 C98043A1680L1 6SE70900XX851DA0 C98O43-A168O-L1 6SE7O9O-OXX85-1DAO

Siemens 6SE7090-0XX85-1DA0 | SIMOVERT MASTERDRIVES CUR Closed/Open-Loop Control Module — Infeed and Regenerative Feedback Units

Part Number: 6SE7090-0XX85-1DA0

Alternate Reference: C98043-A1680-L1

Manufacturer: Siemens AG (Germany)

Product Type: CUR — Closed-Loop and Open-Loop Control Module

Overview

The 6SE7090-0XX85-1DA0 is the CUR (Closed-Loop and Open-Loop Control) module for Siemens SIMOVERT MASTERDRIVES infeed units and infeed/regenerative feedback units (AFE — Active Front End).

his is the control brain of the SIMOVERT infeed section — the module that manages the rectification or active regeneration of power between the industrial AC supply network and the DC bus that feeds the connected drive inverters.

An important ordering note applies to this product: the associated application software, part number 6SW1701-0DA14, must be ordered separately — it is not supplied with the hardware module. The CUR hardware without its matching software cannot be commissioned.

This is essential to verify before placing an order, as receiving the control module without the software results in an incomplete spare and an extended downtime while the software is separately sourced.

The SIMOVERT MASTERDRIVES infeed system — consisting of infeed units (E units) for standard rectification and AFE units (Active Front End / regenerative feedback) for four-quadrant power flow — provides the DC bus supply for one or more inverter drives connected to the same DC link.

The CUR module controls this infeed, ensuring stable DC bus voltage, managed pre-charging, power factor correction in AFE configurations, and — in the AFE case — the ability to regenerate energy from braking drives back into the AC supply.

Key Specifications

CUR Module — Infeed and AFE Control

In a SIMOVERT MASTERDRIVES multi-drive system, the DC bus is not simply connected directly to the AC supply.

An infeed unit sits between the AC network and the DC bus. The infeed unit rectifies the AC supply to DC for the connected inverters, manages pre-charge of the DC bus capacitors at startup (preventing inrush current damage), and in AFE configurations, also controls the AC-side current waveform using IGBT-based switching rather than passive thyristors.

The 6SE7090-0XX85-1DA0 CUR module is the electronics assembly that implements all of this control.

It contains the microprocessors running the DC bus voltage regulation loop, the AC-side current control for AFE operation, the pre-charge sequencing logic, and the protection functions that monitor the infeed for overvoltage, overcurrent, and network fault conditions.

For AFE (Active Front End) infeed units, the CUR module runs the advanced control algorithms that enable two key capabilities: sinusoidal mains current (minimal harmonics injection into the supply network), and regenerative feedback (returning braking energy from drive inverters back into the AC network rather than dissipating it in braking resistors). In energy-intensive industrial applications — large material handling systems, test stands, rolling mills — this regeneration capability represents significant energy savings.

Software Ordering Requirement

The note in the product description — "ORDER associated software supports 6SW1701-0DA14 at T434E" — is a critical purchasing requirement. The 6SE7090-0XX85-1DA0 hardware module is a blank control board on its own.

The drive's firmware for the infeed function is loaded from a software media package ordered separately as 6SW1701-0DA14.

This two-part ordering model was standard practice for SIMOVERT MASTERDRIVES control modules of this generation.

It allowed Siemens to update the firmware without requiring a hardware replacement, and allowed sites to upgrade their infeed functionality by loading newer software on existing hardware.

The consequence for spare parts ordering is that the hardware and software must both be in the order — receiving only the hardware delivers an incomplete spare.

If a site already has the software package from the original installation, it does not need to be re-ordered when replacing the hardware.

The software package can be loaded onto the new hardware module. 

Confirm the software version compatibility between the site's existing package and the replacement hardware module before assuming the original software is transferable.

Dimensions and Physical Installation

The 6SE7090-0XX85-1DA0 measures 260 mm × 330 mm × 95 mm — substantially larger than the plug-in option boards in the SIMOVERT drive electronics box. This is not a plug-in card but a complete electronics sub-assembly that mounts into the infeed unit's electronics compartment.

The installation is a module-level replacement, requiring access to the infeed unit's electronics compartment, correct ribbon and discrete cable disconnections and reconnections, and mechanical re-securing of the module in its mounting position.

FAQ

Q1: The SIMOVERT infeed unit shows a constant F054 (DC link overvoltage) fault immediately after the pre-charge sequence completes. The DC bus capacitors have been checked and are within tolerance. Could the 6SE7090-0XX85-1DA0 CUR module be at fault?

F054 immediately after pre-charge can indicate a CUR module fault in the DC bus voltage measurement circuit — the CUR measures the DC bus voltage and uses it in its regulation loop. A drifted or failed measurement produces an incorrect voltage reading that the CUR's voltage regulation loop interprets as an overvoltage.

Verify the CUR's DC bus voltage measurement against an external meter reading. 

A significant discrepancy between the CUR's measured value and the actual DC bus voltage confirms a measurement circuit fault on the CUR module.

Q2: A replacement 6SE7090-0XX85-1DA0 has been ordered but the software 6SW1701-0DA14 was not included in the order. Can the drive be restarted using the software from the old CUR module?

If the old CUR module's software is accessible (the module is not physically destroyed), the software can sometimes be transferred — but this depends on the specific software loading method supported by the firmware version.

In many SIMOVERT configurations, firmware is loaded via a memory card or USB/serial connection using DriveMonitor software, and a software backup from the old module can be loaded onto the new hardware. 

However, if the old module is inaccessible or destroyed, the 6SW1701-0DA14 software package must be ordered. Do not attempt to run the CUR module without verified compatible firmware.

Q3: The 6SE7090-0XX85-1DA0 was discontinued in October 2011. Is there a SINAMICS equivalent for sites planning a modernisation?

The successor to the SIMOVERT MASTERDRIVES infeed architecture in the SINAMICS platform is the SINAMICS S120 Active Line Module (ALM) for regenerative infeed applications, or the SINAMICS S120 Basic Line Module (BLM) for standard non-regenerative infeed.

These modules provide equivalent infeed and AFE functionality with updated hardware and SINAMICS control architecture.

Retrofitting from SIMOVERT infeed to SINAMICS S120 requires a complete hardware replacement of the infeed section and re-commissioning with SINAMICS-specific parameters and firmware.

Q4: After installing the 6SE7090-0XX85-1DA0 and loading the software, the AFE infeed shows satisfactory DC bus regulation but the power factor correction is significantly worse than before the replacement. What should be checked?

Degraded power factor correction after CUR replacement typically indicates that the AC current control parameters — the PI gains for the active current regulator — are not correctly matched to the supply transformer and cable impedances of the specific installation.

These parameters are tuned during the original commissioning and should have been documented. If the original parameter backup was loaded, verify that the power factor correction setpoint and the AC current regulator gains match the original commissioning data.

If no parameter backup is available, the AC current control loop requires re-commissioning using the transformer's impedance data and the site's supply characteristics.

Q5: The infeed unit with the 6SE7090-0XX85-1DA0 is in a four-quadrant drive system for a large crane application. The CUR has failed during a full-load regenerative braking event. Should the cause of the regenerative fault be investigated before installing the replacement module?

Yes — always investigate the cause of a failure during a specific operating condition before replacing a module. A CUR failure during maximum regenerative braking suggests either that the regenerative current exceeded the module's or infeed unit's rating, or that a grid event (voltage spike, phase loss) occurred during the braking transient.

Installing a replacement CUR without addressing the root cause risks damaging the new module under the same conditions. Review the infeed unit's fault log and the PROFIBUS/USS data captured at the time of the fault. 

Check the AC supply voltages during the regenerative event. Confirm that the regenerative power setpoint in the drive parameters does not exceed the infeed unit's rated regenerative capacity.