Product Information

Mechanical
Reference Point
Accessory for Multi-Section
Linear Encoders

03/2020

Mechanical reference point
Accessory for multi-section linear encoders• Definite reference between scale tape and machine base
• Increases repeatability when positioning• Reduces deviations resulting from a unilateral thermal load

Mechanical reference point for LC 201

ML 400200±0.15



max. R1X
2:1

60±0.15 
A
X

A-A

1:2



B

ISO 4762 - M6; Md = 8 Nm
(ISO 4762 - M5; Md = 5 Nm)

50min. 40

 BAB-B50

ISO 7092 - 6(ISO 7090 - 5)
K = Required mating dimensions
1 = Mating surfaces
2 = Scale-tape clamping

Mechanical reference point for LB 302
ML 400200±0.15



max. R1X
2:160±0.15 A


A
X

A-A50

1:2min. 40

 B

B

ISO 4762 - M6; Md = 8 Nm
(ISO 4762 - M5; Md = 5 Nm)

B-B

50

ISO 7092 - 6(ISO 7090 - 5)

K = Required mating dimensions
1 = Mating surfaces
2 = Scale-tape clamping

Product Information: Mechanical Reference Point    03/2020

Thermal characteristics
Machine parts expand under the influenceof heat, thus causing position deviations
during machining. In order to minimize
these thermal influences, linear encoders
are mounted on the machine base in sucha way that the measuring standard of thelinear encoder adapts itself to the actual
thermal expansion of the machine base.
However, on machine components withlarge dimensions, asymmetricaltemperature influences can lead todeviations if, for example, the machinebase heats up on only one side. The
mechanical reference point can be used toestablish a stable fixed point relative to themachine base at any location (e.g. center ofa rotary table). This increases thereproducibility at this fixed point evenunder unstable thermal conditions.

Mechanical reference point on a machine tool

Function
The mechanical reference point clamps thescale tape of multi-section linear encoders
at a freely selectable location on themachine base. This establishes a definite
reference between the scale tape and themachine base. The mechanical reference
point is used when increased repeatability
is required when moving to a certain
position relative to the machine base.
Technical description
The mechanical reference point consists ofa 400 mm long scale-housing section witha steel clamping device in the middle (seefigures 1 and 2). The clamping device andhousing are connected through solid-state
joints in order to avoid thermal influences
between the clamping device and housing.
The scale-tape housing and the clamping
device are each screwed to the machinebase. After the multi-section linear encoder
has been completely mounted, the scaletape is clamped with the clamping screwof the clamping device, thus creating afixed connection between the scale tapeand the machine base.

Figure 1: Mechanical reference point for LC 201

Features of the mechanical reference point
for multi-section systems:• Can be mounted at any position• Easy and reliable mounting• Provides a stable fixed point relative tothe machine base over the entire
operating temperature range of themachine
Mechanical reference pointLC 201
ID 1200973-01
LB 382
ID 1223300-01
Figure 2: Mechanical reference point for LB 382

Product Information: Mechanical Reference Point    03/2020           

1305907 · 00 · A · 02 · 03/2020 · PDF

This Product Information document supersedes all previous editions, which thereby
become invalid. The basis for ordering from HEIDENHAIN is always the Product
Information document valid when the contract is made.

Further information:
Comply with the requirements described in the following documents to ensure correct
operation of the encoder:• Brochure: Linear Encoders for Numerically Controlled Machine Tools
ID 571470-xx• Mounting Instructions: Mechanical Reference Point for LC 201
ID 1210007-90• Mounting Instructions: Mechanical Reference Point for LB 382
ID 1234488-90