Signal Connector And Power Connector 6FX2003-7FX00 6FX2 003-7FX00 6FX2OO3-7FXOO

Siemens 6FX2003-7FX00 | MOTION-CONNECT HF Clamp — For Signal Connector and Power Connector Size 1, Metal Shield Grounding Clamp, 0.04kg, EMC Cable Screen Termination

Overview

The Siemens 6FX2003-7FX00 is the HF clamp — a small but functionally critical component in any MOTION-CONNECT cable assembly where the cable shield must be properly grounded at the connector. In the broader context of a servo drive installation, where variable-frequency drives switch currents at high frequency and generate significant electromagnetic emissions, the cable shield is not a courtesy — it is the engineering mechanism that keeps those emissions from radiating into adjacent signal wiring, sensor circuits, and communication cables.

The HF clamp is how that shield connects to ground at the connector end.

Servo cables in SINUMERIK and SINAMICS installations carry high-frequency noise sources: the PWM switching frequencies of the drive amplifier are superimposed on the fundamental motor current, and without containment, these frequencies radiate from the cable into the surrounding installation.

Shielded cable — with a metallic braid or foil surrounding the conductors — contains this radiation, but only if the shield is properly terminated at both ends of the cable.

Termination means a 360° electrical connection from the shield to the metallic connector housing, and from the housing to the machine frame ground. 

A shield that is merely twisted into a pigtail and connected to a single terminal is not a properly terminated shield — the pigtail has inductance that blocks high-frequency currents, and the single-point connection is not 360° contact.

The 6FX2003-7FX00 HF clamp creates the 360° shield termination mechanically: the clamp is positioned around the cable at the connector entry point, clamping down on the folded-back shield braid to make electrical contact around the cable's full circumference.

This circumferential contact is what low-impedance, high-frequency grounding actually means — current flowing along the shield finds a low-resistance path to the connector housing (which is then connected to machine ground through the mounting structure) at every point around the cable, not just at one terminal.

Key Specifications

What "HF Clamp" Means — High-Frequency Shielding in Practice

The designation "HF" (Hochfrequenz — High Frequency) is specific: this is not a general-purpose cable grip or strain relief. Its purpose is the electrical termination of the cable shield at radio-frequency impedances.

At low frequencies (50/60Hz mains and audio frequencies), a pigtail connection of the shield might perform adequately because the inductance of the pigtail is negligible.

At the switching frequencies of modern servo drives — typically 4kHz to 16kHz carrier frequencies, with harmonics extending much higher — even a few centimetres of pigtail wire has enough inductance to significantly degrade the shield's effectiveness. 

The HF clamp replaces the pigtail with a direct, short, low-inductance contact across the full 360° circumference of the cable.

In practical terms, this means that a servo cable assembly using the 6FX2003-7FX00 HF clamp will pass the EMC emissions tests (typically EN 55011 or IEC 61800-3) that demonstrate the installation does not generate excessive radiated or conducted emissions.

A cable assembly without proper HF clamping may fail these tests — and even if it passes in isolation, it may cause interference problems in the specific installation where it is deployed. Siemens's MOTION-CONNECT documentation makes proper HF clamping a mandatory requirement, not an option, for EMC-compliant cable termination.

Assembly Sequence — Where the HF Clamp Fits in the Connector Build

In a MOTION-CONNECT cable assembly, the HF clamp is installed as part of the cable preparation before the connector housing is assembled. The typical sequence for a Size 1 connector assembly with HF clamp:

The cable outer jacket is removed over a defined length, exposing the shield braid.

The shield braid is folded back over the jacket — turning the inner surface outward to create a metallic band around the outside of the cable at the connector entry point.

The HF clamp is then positioned over this folded-back braid and tightened, creating the 360° electrical connection between the braid and the clamp. 

The clamp assembly then enters the connector housing's cable entry, where the connector's strain relief structure engages both the clamp and the cable, securing the assembly mechanically while maintaining the electrical shield continuity.

The resulting assembly has the shield braid directly connected to the metallic connector housing through the HF clamp — with no pigtail, no loose end, and no gap in the circumferential contact.

The connector housing then connects to ground through the cable's mating connector on the motor or drive, which is itself mounted to the grounded machine structure.

Connector Size 1 Compatibility

The "Size 1" designation in the 6FX2003-7FX00 description refers specifically to the MOTION-CONNECT Size 1 connector family — the range of signal connectors (such as 6FX2003-0SA-series) and power connectors (such as 6FX2003-0LA00, 6FX2003-0LU00) that handle cable conductors in the 1–2.5mm² (power) and 0.08–0.56mm² (signal) cross-section ranges.

The HF clamp's dimensions are matched to the cable diameter range of Size 1 cables and to the entry geometry of the Size 1 connector housing.

Using the 6FX2003-7FX00 HF clamp with larger Size 1.5 or Size 2 connectors — which have wider cable entry dimensions and thicker cables — is not appropriate; those connector sizes have their own HF clamp accessories sized for the larger cable diameters.

Matching the clamp size to the connector size is essential for achieving the clamping force and 360° contact required for effective shield termination.

FAQ

Q1: Is the HF clamp a single-use component, or can it be reused if the cable is disassembled?

The 6FX2003-7FX00 HF clamp can technically be reused if it is removed carefully without deformation and the cable braid is in good condition. However, in practice, cable disassembly often distorts the folded-back shield braid, and the clamp itself may be deformed by the clamping action.

For maintenance situations where a cable end is rebuilt, replacing the HF clamp with a new one from the MOTION-CONNECT accessories stock is the reliable approach — the component cost is minimal relative to the labour cost of cable assembly, and a new clamp guarantees the clamping force specification.

Q2: Can the cable be assembled without the HF clamp in the field if none is available?

Technically, the connector can be assembled without the HF clamp, but this leaves the shield ungrounded at the connector — the connector housing and the cable braid will have no reliable electrical connection, and the shield will not provide effective HF noise containment at that cable end. In a low-noise environment, the degraded shielding may not cause visible problems.

In a typical SINAMICS servo drive cabinet with multiple drives switching simultaneously, the lack of proper shield termination at a cable end frequently results in ground loop noise, encoder signal corruption, or EMC compliance failure.

Siemens's cable assembly documentation specifies the HF clamp as a required component.

Q3: How many HF clamps are required per cable — one or two?

Each cable end requires its own HF clamp — one at the motor connector end and one at the drive/module connector end.

A complete cable has two connectors (one at each end), so two HF clamps are required per cable. 

In cases where only the connector at one end of an existing cable is being rebuilt (field repair of a damaged connector), only one clamp is needed for that assembly.

Q4: What is the difference between the HF clamp and the standard cable strain relief that comes with the connector kit?

The standard strain relief termination included in connector kits (such as the cable grip / cable termination for outer diameter) provides mechanical securing — it prevents the cable from being pulled out of the connector under tension.

The HF clamp provides electrical shielding — it grounds the shield braid to the connector housing. 

Both components serve different functions and are used together in a complete assembly: the strain relief secures the cable mechanically, and the HF clamp grounds the shield electrically.

Omitting either one compromises either mechanical security or EMC performance.

Q5: Are there different HF clamp part numbers for different connector sizes within MOTION-CONNECT?

Yes. The MOTION-CONNECT connector range spans multiple sizes (Size 1, Size 1.5, Size 2, Size 3) with different cable diameter ranges. Each size has a corresponding HF clamp accessory sized appropriately.

The 6FX2003-7FX00 is specifically for Size 1 signal and power connectors. Size 1.5 and larger connectors use different HF clamp part numbers from the 6FX2003-7xx series.

When ordering HF clamps for a cable assembly, the clamp part number must match the connector size used in the assembly.