Siemens Simodrive 611 Digital High Performance Direct MEAS System 6SN1118-0DK23-0AA0

6SN1118-0DK23-0AA0 | Siemens SIMODRIVE 611-D Digital Performance Module — Closed-Loop / Direct Measuring System / CNC Performance Control Unit

6SN1118 — SIMODRIVE 611-D Performance Control Unit Family

The 6SN1118-0DK23-0AA0 belongs to the 6SN1118 performance control unit family — the plug-in modules that provide the intelligence layer within SIMODRIVE 611-D drive modules. Within the 6SN1118-0Dxx23 sub-family:

The DK23 designation within 6SN1118 identifies a specific combination of axis configuration and measuring system type — distinguished from the DG21 (1-axis, described above) by the "K" configuration letter and the "23" variant code.

Key Specifications

Applications — Where Direct Measurement Matters

High-precision machining centres: Five-axis machining of aerospace components, die and mould machining, and precision jig boring — where axis positioning errors from lead screw pitch error or thermal drift would propagate directly to dimensional errors on the workpiece.

Grinding machines: Precision grinding requires maintaining micron-level position accuracy throughout long grinding cycles despite thermal expansion. Direct measuring via linear encoders corrects for this expansion in real time.

CMM (Coordinate Measuring Machine) axes: Measuring machine axes must have verified position accuracy independent of mechanical wear — direct encoders provide this independently of the ball screw or rack's condition.

Application Scenarios

SIMODRIVE 611-D direct measuring axis fault: A CNC machine tool with direct measuring axes develops position control errors on one axis — the closed-loop performance module with direct measuring capability is identified as the fault. 6SN1118-0DK23-0AA0 is fitted as the replacement. Correct high-accuracy position control is restored.

High-precision machining centre drive commissioning: A precision machining centre with linear encoders on all axes is being commissioned with SIMODRIVE 611-D drives. 6SN1118-0DK23-0AA0 is installed in each drive module that connects to a direct measuring axis.

FAQ

Q1: What is the practical accuracy improvement from direct measuring over motor-only feedback?

Positioning accuracy from motor encoder alone is limited by lead screw pitch error, lead screw thermal expansion, and backlash. Typical lead screw systems achieve ±5–15 microns of positioning accuracy. With direct linear encoder measurement via a module like 6SN1118-0DK23-0AA0, the position loop closes on the actual axis position — eliminating pitch error and thermal drift from the error budget, achieving ±1–3 microns depending on the encoder resolution.

Q2: What encoder types are supported by 6SN1118-0DK23-0AA0 for the direct measuring channel?

The SIMODRIVE 611-D direct measuring performance modules accept high-resolution linear or rotary encoders for the direct measurement channel — typically Heidenhain or equivalent linear scales with sin/cos 1Vpp or digital interfaces. The specific encoder type and resolution supported by 6SN1118-0DK23-0AA0 are confirmed from the applicable Siemens SIMODRIVE 611-D function descriptions and hardware documentation.

Q3: Can 6SN1118-0DK23-0AA0 be used without a direct measuring encoder — using the motor encoder only?

A direct measuring performance module can typically operate in motor encoder-only mode when the direct encoder input is not connected — but this negates the purpose of the higher-specification module. Using 6SN1118-0DK23-0AA0 without a direct encoder substitutes a standard performance module and does not take advantage of the direct measuring capability. Confirm from SIMODRIVE 611-D documentation whether motor-encoder-only operation is supported for this specific variant.

Q4: Does replacing 6SN1118-0DK23-0AA0 require parameter backup and restoration?

Yes — SIMODRIVE 611-D performance control units store axis-specific drive parameters. When replacing 6SN1118-0DK23-0AA0, the drive parameters (including both the motor encoder and direct encoder configuration data) must be backed up before removal and restored to the replacement unit via the SINUMERIK CNC's drive data management function. Particular attention is needed to the direct encoder scaling parameters — these must be correctly set for the specific linear scale installed on the machine axis.