Modular Angle
Encoders
with Scale Drumor Scale Tape

08/2023

Table of contents

Overview
Angle encoders from HEIDENHAIN

4

Selection guide6Technical features and mounting information
Measuring principles

12

Scanning principles

14

Measurement accuracy

16

Reliability

22

Angle encoders on direct-drive motors

24

Mechanical design types and mounting

25

General information

34

Functional safety

36

Specifications

Series or model

Modular angle encoders
with optical scanning and scale drum

ECA 4400 series40

ERA 4000 series

48

Modular angle encoders
with magnetic scanning and scale drum

ECM 2400 series

58

ERM 2000 series

64

Modular angle encoders
with optical scanning and scale tape

ERA 7000 series76

ERA 8000 series

80

Further information
Testing equipment and diagnostics

Information on• Sealed angle encoders• Rotary encoders• Encoders for servo drives• Exposed linear encoders• Linear encoders for numericallycontrolled machine tools• HEIDENHAIN interface electronics• HEIDENHAIN controls
is available upon request as well as on theInternet at www.heidenhain.com.

2

This brochure supersedes all previous editions, which thereby become invalid.
The basis for ordering from HEIDENHAIN is always the brochure edition valid when
the order is placed.
Standards (ISO, EN, etc.) apply only where explicitly stated in the brochure.

Further information:
For comprehensive descriptions of all available interfaces, as well as general electricalinformation, please refer to the Interfaces of HEIDENHAIN Encoders brochure.

84

Angle encoders from HEIDENHAIN

Angle encoders are used in applications
requiring angular measurement at highresolution or at accuracies of down to justa few arc seconds.
Examples:• Rotary tables on machine tools• Swivel heads on machine tools• C axes on lathes• Measuring machines for gears• Printing units of printing machines• Spectrometers• Telescopes

ECA 4000 absolute angle encoder

Modular angle encoders
with optical scanning
The ERP, ERO, ERA and ECA modular
angle encoders are particularly well suitedfor high-accuracy applications with low
installation space. Particular benefits:• Wide hollow-shaft diameter (of up to 10 mwith a scale tape)• High shaft speeds of up to 20 000 rpm• No additional starting torque from shaft
seals• Segment solutions• Also available with functional safety
Modular angle encoders with opticalscanning are available with various
graduation carriers:• ERP/ERO: Glass circular scale with hub• ERA/ECA 4000: Steel drum
• ERA 7000/8000: Steel scale tape

By contrast, rotary encoders are used inapplications where accuracy requirements
are less stringent, including automation,
electric motors and many otherapplications.

Because these angle encoders do notcome with an enclosure, the required
degree of protection must be ensured
through proper installation.

Angle encoders differ in terms of thefollowing physical design characteristics:
Sealed angle encoders with a hollow
shaft and stator coupling
The stator coupling is designed so that the
coupling absorbs only the torque arisingfrom bearing friction, especially during
angular acceleration of the shaft. These
angle encoders therefore provide excellent
dynamic performance. Due to the stator
coupling, the stated system accuracy
includes the error of the shaft coupling.
The RCN, RON and RPN angle encoders
have an integrated stator coupling, while
the ECN is externally mounted.
Other benefits:• Compact size for limited installation
space• Hollow shaft diameters of up to 100 mm• Easy installation• Also available with functional safety

4

ECM 2000 absolute angle encoder

Modular angle encoders
with magnetic scanning
Thanks to their robust design, the ERM
and ECM modular angle encoders arehighly immune to cooling lubricant andcontamination in production machines.
They are ideal for medium to high accuracy
requirements and low installation space:• Large shaft diameters• High shaft speeds of up to 60 000 rpm• No additional starting torque from shaft
seals• High immunity to contamination• Available with functional safety

RCN 8000 absolute angle encoder5

Selection guide
Modular angle encoders with optical scanning and a scale drum

SeriesOverall dimensions
in mm
2)

ECA 4400

ECA 4402

Diameter

Accuracy ofgraduation

Mechanicallypermissible
speed1)

DesignSignal periods/
revolution

Interface

Reference
marks

Page

D1:	70 mm
to
512 mmD2:	104.63 mm
to560.46 mm

±3.7”
to
±2”

 15 000 rpm3)to 2750 rpm

Steel drum withcentering collar

–

–

40

±3”
to
±1.5”

 15 000 rpm
to 2750 rpm

Steel drum withthree-point centering

EnDat 2.2
Fanuc
Mitsubishi
Panasonic
Yaskawa

ECA 4000

ERA 4x00

D1:	40 mm
to
512 mmD2:	76.5 mm
to560.46 mm

±5”
to
±2”

 20 000 rpm 3)
to 2750 rpm

Steel drum withcentering collar

3000 to 52 000» 1 VPP« TTLDistance-coded
or one48

ERA 4202

D1:	40 mm
to270 mmD2:	76.5 mm
to331.31 mm

±4”
to
±1.7”

 20 000 rpm
to 4750 rpm

Steel drum withthree-point centering

12 000 to 52 000» 1 VPP« TTLDistance-coded
or one52

ERA 4000

1)

May be limited during operation by the electrically permissible shaft speed
Also available with functional safety
3)
Limited in the case of mechanical fault exclusion
2)

6

7

Modular angle encoders with magnetic scanning and a scale drum

SeriesDiameter

Accuracy ofgraduation

Mechanicallyperm. speed

DesignSignal periods/revolution Interface

Page

ECM 2400

D1: 70 mm
to
260 mmD2: 113.16 mm
to326.9 mm

±8”
to
±3.5”

14 500 rpm
to4500 rpm

Fastening via screws

900 to 2600

EnDat 2.2
Fanuc
Mitsubishi

58

ERM 2200

D1: 40 mm
to410 mmD2: 64.37 mm
to452.64 mm

±12”
to
±2.5”

22 000 rpm
to3000 rpm

Fastening via screws

1024 to 7200

 1 VPPERM 2203

D1: 40 mm
to295 mmD2: 64.37 mm
to326.90 mm

±8”
to
±1.5”

22 000 rpm
to4500 rpm

1024 to 5200

ERM 2400

D1: 40 mm
to
512 mmD2: 64.37 mm
to603.52 mm

±13”
to
±3”

22 000 rpm
to1600 rpm

512 to 4800

« TTL
 1 VPPEnDat 2.2

68

ERM 2404

D1: 30 mm
to100 mmD2: 45.26 mm
to128.75 mm

±24”
to
±9”

60 000 rpm
to20 000 rpm

360 to 1024

 1 VPP70

ERM 2904

D1: 35 mm
to
100 mmD2: 54.43 mm
to120.96 mm

±72”
to
±33”

50 000 rpm
to
16 000 rpm

D1: 40 mm;
55 mm
D2: 64.37 mm;
75.44 mm

±17”
to
±14”

33 000 rpm;
27 000 rpm

ERM 24058Overall dimensions
in mm

ECM 2400

Friction-locked fastening
through clamping of thedrum

180 to 400

64

66

ERM 2203

70
ERM 2404

Friction-locked fastening
through clamping of thedrum; additional slot formachine key as antirotation element

512; 600

71

9Modular angle encoders with optical scanning and a scale tape

SeriesDiameter

Accuracy ofgraduation

Mechanicallypermissible
speed1)

DesignSignal periods/ Interface
revolution

Reference marks Page

ERA 7000

458.62 mm
tomax. 3000 mm
upon request

±3.9”
to
±0.7”

 250 rpm
toapprox. 85 rpm

For inner mounting,full-circle and segment2)
version

36 000 to 230 000

» 1 VPPDistance-coded76

ERA 8000

458.11 mm
tomax. 3000 mm
upon request

±4.7”
to
±0.9”

 50 rpmto 15 rpm

For outer mounting,full-circle and segment
version2)

36 000 to 230 000

» 1 VPPDistance-coded80

ERA 8900

 3000 mm
upon request

Upon request

Upon request

Outer mounting, very
wide operating tolerances,full-circle and segment
version2)

Upon request» 1 VPPDistance-codedUpon
request1)
2)

Overall dimensions
in mm

May be limited during operation by the electrically permissible shaft speed
Segment solutions upon request

10

ERA 7000

ERA 8000

11

Measuring principles
Measuring standard

HEIDENHAIN encoders use measuring
standards consisting of periodic structures
known as graduations. The opticalgraduations are applied to a glass or steel
carrier substrate. For encoders with large
measuring lengths, the graduation carrier isa steel tape.
HEIDENHAIN manufactures the precision
graduations in the following speciallydeveloped, photolithographic processes:• METALLUR: contamination-tolerant
graduation consisting of metal lines ongold; typical grating period: 20 μm• SUPRADUR phase grating: opticallythree-dimensional, planar structure;
particularly tolerant to contamination;
typical grating period: 8 μm and finer• OPTODUR phase grating: opticallythree-dimensional, planar structure withparticularly high reflectance; typicalgrating period: 2 μm and finer• TITANID phase grating: exceptionallyrobust, optically three-dimensional
structure with a high degree ofreflectance; typical grating period: 8 µm

Absolute measuring method

Incremental measuring method

In the absolute measuring method, theposition value is available immediately
upon encoder switch-on and can berequested by the downstream electronics
at any time. There is no need to move theaxes to find the reference position. Instead,the absolute position information is readfrom the graduation on the measuring
standard, which is designed as a serial
absolute code structure. To obtain theposition value, a separate incremental trackis interpolated.

In the incremental measuring method,
the graduation is a periodic grating
structure. The position information is
obtained through counting the individual
increments (measuring steps) starting at afreely selectable point of origin. Since
position measurement requires anabsolute point of reference, the measuring
standard features an additional track
containing a reference mark. The absolute
position on the scale, established by thereference mark, is gated with exactly one
measuring step.

Number of signal periods based on
graduation period
20 µm
40 µm
80 µm
     –
8 192     –
12 000     –
16 38420 00024 000     –
28 00032 76840 00048 00052 000     –
     –The reference mark must therefore be
traversed before an absolute point ofreference can be established or before themost recently selected reference point isrefound.

Graduation of absolute angle encoders

Along with the very fine grating periods,
these processes permit high edge
definition and excellent homogeneity of
the graduation. In combination with thephotoelectric scanning method, thesecharacteristics are critical for attaining
high-quality output signals.
Magnetic encoders use a graduation carrier
made of a magnetizable steel alloy. A write
head creates strong local magnetic fields
in different directions, resulting in a
graduation consisting of magnetically northand south poles (MAGNODUR procedure).
In combination with the magnetoresistive
scanning method, this technology delivers
a measuring method that is robust despite
environmental factors.

Home position
Schematic representation of a circular graduation with distance-codedreference marks (example for ERA 4480 with 20 000 lines)

12

Graduation drum: TTR ERA 4000 C

In some cases, this may require rotation
by up to nearly 360°. To simplify thesereference runs, many HEIDENHAIN
encoders feature distance-codedreference marks: the reference-mark track
contains multiple reference marks at
different defined intervals. The downstream
electronics determine the absolutereference point after just two neighboringreference marks have been traversed; inother words, after just a few degrees ofrotational motion (see “Nominal increment
N” in the table). Encoders with distancecoded reference marks are identified witha “C” after the model designation (e.g.,
TTR ERA 4200 C).

3 000
4 096
5 000
     –
7 000
8 192
10 000
12 000
13 000     –
     –
     –
     –
     –
     –
     –

     –
4 096     –
6 000     –
8 192
10 000
12 000     –
14 00016 38420 00024 00026 00038 00044 000

Number of Nominalreference increment
marks
N
120°
90°
72°
60°
51.429°45°
36°30°
27.692°25.714°
22.5°
18°
15°
13.846°  9.474°  8.182°

6
8
10
12
14
16
20
24
26
28
32
40
48
52
76
88

Graduation drum: TTR ERM 2200 C
Number of
signal periods

Number ofreference marks

Nominalincrement N

1024
1200
1440
1800
2048
2400
2800
3392
4096
5200
7200

16
24
30
36
32
40
50
32
64
52
90

45°
30°
24°
20°
22.5°
18°
14.4°
22.50°
11.25°
13.85°
8°

Scale tape: MSB ERA 7480 C, MSB ERA 8480 C

Graduation drum: TTR ERM 2400 C

Number of
signal periods

Number ofreference marks

Nominalincrement N

Number of
signal periods

Number ofreference marks

Nominalincrement N

36 00045 00090 000

72
90
180

10°
8°
4°

512
600
720
900
1024
1200
1400
1696
2048
2600
3600
3850
4800

16
20
24
30
32
30
40
32
32
52
60
70
80

45°
36°
30°
24°
22.5°
24°
18°
22.5°
22.5°
13.85°
12°
10.3°
9°

13

Scanning principles

HEIDENHAIN encoders employ different
measuring principles. All of these principles
involve detecting exceedingly finegraduation lines on a carrier material andgenerating output signals as a result. The
specific characteristics of the scanningprinciple affect data collection in the target
application and should therefore beproperly matched.
HEIDENHAIN uses two scanning principles
for scale-drum and scale-tape modular
angle encoders:• Optical scanning for the ECA and ERA• Magnetic scanning for the ECM and
ERM

Optical scanning
Put simply, the imaging scanning principle
uses projected-light signal generation:
two gratings with equal or similar grating
periods are moved relative to each other.
These are the scale and the scanning
reticle. The carrier material of the scanning
reticle is transparent. The measuring
standard’s graduation can be applied totransparent or reflective material.

Magnetic scanning
The permanent-magnet MAGNODUR
graduation is scanned by magnetoresistive
sensors. They consist of resistive tracks
whose resistance values change in
response to a magnetic field. Whenvoltage is applied to the sensor, and when
there is relative motion between thescanning head and the scale drum, thecurrent is modulated in accordance withthe magnetic field.

Parallel light passes through a grating
structure, casting dark and light fields at a
certain distance, where there is an index
grating with the same or similar grating
period. When the two gratings move
relative to each other, the incident light ismodulated: If the gaps are aligned, lightpasses through. If the lines of one grating
coincide with the gaps of the other, no lightpasses through. Photocells convert theselight fluctuations into electrical signals. The
specially structured grating of the scanning
reticle filters the light so as to generatenearly sinusoidal output signals. The
smaller the graduation period of the grating
structure, the closer and more tightly
toleranced the gap must be between thescanning reticle and the scale. In encoders
that use the imaging scanning principle,
workable mounting tolerances are
attainable starting at a minimum grating
period of 10 μm.

Scale

The special geometric configuration of theresistive sensors, combined with the
manufacturing process used for thescanning PCBs on glass substrates,
ensures high signal quality. In addition, thelarge scanning surface enables filtering of
the signal harmonics. Such are therequirements for low position error within asignal period.
The graduation periods are at approx.
200 µm to 1000 µm. For this reason,
devices with magnetoresistive scanning
are used in applications with mid-levelaccuracy requirements.
Encoders with MAGNODUR scanning arehighly immune to contamination and are
well suited for use at higher operating
temperatures.

Window

Structured
detector

Measuring standard

Scanning reticle
Condenser lensIndex grating

LED light source
Scanning reticle

Photoelectric scanning in accordance with the imaging principle and single-field scanning

14

Magnetoresistive scanning principle

15

Measurement accuracy
Encoder-specific error

These factors can be divided into encoderspecific error and application-dependent
factors. For assessment of the attainable
overall accuracy, all of these individual
factors must be taken into account.

Encoder-specific error

The encoder-specific error includes:• The graduation accuracy• The interpolation accuracy• The position noise

The graduation accuracy
The graduation accuracy results from thequality of the graduation. It includes:• Homogeneity and period definition of thegraduation• The alignment of the graduation on thegraduation carrier• For encoders with solid graduation
carriers: the stability of the graduation
carrier, ensuring accuracy even after
mounting• For encoders with a steel scale tape:the error due to irregular scale-tape
expansion during mounting, as well as
the error at the scale-tape butt joints infull-circle applications
The accuracy of the graduation is thebaseline error. This accuracy is ascertained
under ideal conditions via measurement of
the position error by means of a serially
produced scanning head. The distance
between the measuring points is
equivalent to the integer multiple of thesignal period. As a result, the interpolation
error has no effect.
For modular angle encoders, thegraduation accuracy is stated in accuracy
grades for easier differentiation. Accuracy
grade a defines the upper limit of thebaseline error within the measuring range.

Interpolation error
within one signal
periodPosition 

Signal level Position error 

Position error within one revolution

Interpolation error 

Accuracy of the interpolation
The interpolation error has an effect even atvery low traversing speeds and causes
speed fluctuations, especially in the speed
control loop. Within the application, theinterpolation error affects the machining
quality, such as the surface quality.

The accuracy of the interpolation is
primarily influenced by:• The fineness of the signal period• The homogeneity and period definitionof the graduation• The quality of scanning filter structures• The characteristics of the sensors• The quality of the signal processing
electronics
These factors are taken into account in thestated interpolation error within one signal
period.
The interpolation accuracy is stated in
the form of a maximum value u of theinterpolation error. For specific values,
see the technical data.
Position noise
Position noise causes small, random
deviations from the expected position.
Position noise is also dependent on signal
processing. Typically, the position noise isless than 1‰ of the signal period.

Application-dependent error

The quality of the mounting and adjustmentof the scanning head, in addition to thegiven encoder-specific error, normally has asignificant effect on the accuracy that canbe achieved by encoders without integral
bearings. Of particular importance are themounting eccentricity of the graduationand the radial runout of the measured
shaft. The application-dependent error
values must be measured and calculated
individually in order to evaluate the overall
accuracy.
In contrast, the specified system accuracy
for encoders with integral bearing alreadyincludes the error of the bearing and theshaft coupling (see the Angle Encoders
with Integral Bearing brochure).

Static hysteresis during magnetic
scanning
Whenever there is a change in direction,
there is also the effect of hysteresis. Thishystersis depends on the size of the signal
period and on the mounting conditions.
HEIDENHAIN therefore recommends
measuring this constant value in order tocompensate for it. The ERM 2203 series
encoders do not exhibit any hysteresis.

Interpolation error u within one signal period

Error due to eccentricity of thegraduation relative to the bearing
Mounting-related eccentricity between
the graduation and the bearing can be
expected during mounting of the disk/hub
assembly, the scale drum or the steel scaletape. Dimensional and geometric errors
exhibited by the mating shaft can also add
to the eccentricity. The following
relationship exists between theeccentricity e, the diameter of thegraduation D and the measurement
error ¹j (see bottom left figure):

Mean graduation diameter D for:ERA 4000
ECA 4000
ERM 2000
ECM 2000D  Drum outside
diameter

ERA 7000
ERA 8000D  Scale mating diameter¹j = ±412 · eD¹j =	Measurement error in ”
(arc seconds)
e =	Eccentricity of the scale drum
relative to the bearing in µm(1/2 radial runout)
D =	Mean graduation diameter in mm
M = Center of graduation
j = “True” anglej‘ = Scanned angle
Calculation example:
ECA 4000 angle encoder with a drum
outside diameter of 208.89 mm, radial
runout of the scale drum 2 µm
( eccentricity of 1 µm)¹j = ±412 ·1
 ±2.0”208.89Alternative: Use the graph at the bottom
right

Scanning unit

Signal period
360 °elec.

Measurement error ¹j in angular seconds 

The accuracy of angular measurement ismainly determined by:• The quality of the graduation• The stability of the graduation carrier• The scanning quality• The quality of the signal processing
electronics• The eccentricity of the graduation
relative to the bearing• The bearing error• The coupling to the measured shaftMean graduation diameter D in mm 
Eccentricity of the graduation relative to the bearing

16

Resulting measurement error ¹j for various eccentricities e as a functionof the mean graduation diameter D (with graph-reading example)

17

Calibration chart

Radial runout error of the bearing
The function for finding the measurement
error ¹j also applies to the radial runout
error of the bearing when the eccentricity(half of the displayed radial runout error) is
entered for e. The mechanical complianceof the bearing under radial shaft loads
causes similar errors.
Deformation of the graduation resulting
from mounting
Characteristics of the scale drums, such as
their cross section, reference surfaces,
screw holes and the position of thegraduation relative to the mounting
surface, are designed such that theaccuracy of the encoders is only marginallyaffected by mounting and operation.

Geometric and diameter errors of the
bearing surface (for ERA 7000 and
ERA 8000)
Geometric errors of the bearing surface
can affect the attainable system accuracy.

This error can be eliminated if the signal
period per 360° z’ that is valid for the actual
scale-tape carrier diameter D’ can beentered into the controller. The following
relationship is valid:

The segment solutions exhibit additional
angular error ¹j if the nominal scale-tapediameter is not precisely complied with:z‘ = z · D‘/D

¹j = (1 – D‘/D) · j · 3600
With
¹j = Error for segment in arc seconds
j = Segment angle in degrees
D = Nominal scale-tape carrier diameter
D’ = Actual scale-tape carrier diameterWithz = Nominal signal period per 360°z‘ = Actual signal period per 360°
The angle actually traversed in segment
solutions should be measured with acomparative encoder, such as an angle
encoder with an integral bearing.

All modular angle encoders from
HEIDENHAIN are inspected for proper
functioning prior to shipping and for
accuracy during final acceptance. For the
ECA 4000, ERA 4000, ECM 2400 and
ERM 2203, HEIDENHAIN prepares quality
inspection documents and includes themwith the scale drums.
The quality inspection document
confirms the stated graduation accuracyof each scale drum and documents
measurement parameters along with themeasurement uncertainty. The calibration
standards ensure the traceability, as
required by EN ISO 9001, to recognizednational or international standards.

HEIDENHAIN

Qualitätsprüfbescheinigung

TTR ERM 2203C
ID 1144130-06
SN 76551553

Positionsabweichung ΔPos in Winkelsekunden
Position error ΔPos in angular seconds

8,0

4,0

The graduation accuracy is determinedwhen a single revolution is traversed,
resulting in the display of a measurement
curve and the value of the maximum error.
The mounting-specific error is not included,
nor is interpolation error within one signal
period, which is a characteristic of thescanning head.
Temperature range
The angle encoders are inspected at areference temperature of 22 °C. This is
the temperature at which the systemaccuracy provided in the calibration chart
is valid.

0,0

1

-4,0

-8,0

0

90

↑Nullpunkt
Zero point

180

Die Messkurve zeigt die Positionsabweichungen der Teilungstrommel
bei einer Umdrehung.

The line count of the scale drum is 2048.

Positionsabweichung ΔPos der Teilungstrommel: ΔPos = PosS - PosE
PosS = Position des Vergleichnormals (Standard)
PosE = Position des Prüflings

Position error ΔPos of the scale drum: ΔPos = PosS - PosE
PosS = position measured by the reference standard
PosE = position measured by the measured encoder

Maximale PositionsabweichungMaximum position error

der Messkurve innerhalb 360°

± 1,43''of the error curve within 360°

± 1.43''

Unsicherheit der Messmaschine

Uncertainty of the measuring machine

0,05"

0.05"

360

Position PosE in Grad
Position PosE in degrees

2

Measurement parameters

Messgeschwindigkeit

33 min‫־‬¹

Measuring velocity

33 min‫־‬¹

Anzahl der Messpositionen pro Umdrehung

2048

Number of measuring positions per revolution

2048

Diese Teilungstrommel wurde unter strengen
HEIDENHAIN-Qualitätsnormen hergestellt und geprüft.
Die Positionsabweichung liegt bei einer Bezugstemperatur
von 22 0C innerhalb der Genauigkeitsklasse ± 4,0''.

Segment version

270

The error curve shows the position errors in one revolution of
the scale drum.

Die Strichzahl der Teilungstrommel beträgt 2048.

Messparameter

Encoder-specific error in arc seconds 

Quality Inspection Document

This scale drum has been manufactured and inspected inaccordance with the stringent quality standards of HEIDENHAIN.
The position error at a reference temperature of 22 0C lies within
the accuracy grade ± 4.0''.

Kalibriernormal

Kalibrierzeichen

Calibration standard

ERP 880

102 D-K-19057-01-00 2016-05

ERP 880

DR. JOHANNES HEIDENHAIN GmbH.

Calibration mark102 D-K-19057-01-00 2016-05

83301 Traunreut www.heidenhain.de Telefon: +49 8669 31-0 Fax: +49 8669 32-5061.

.

.

29.06.2021

Prüfer/Inspected by

M. Urland

Sample calibration chart for an ERM 2203 C scale drum
1 Graphical depiction of the graduation accuracy
2 Calibration result

Mating diameter in mm 
Segment

Encoder-specific error with ERA 7000 and ERA 8000

Center of graduation

18

Angular error resulting from variations in the scale-tape carrier diameter

19Compensation possibilities

Reasons for compensation
For modular angle encoders, the statedencoder-specific error is based on ideal
mounting. In the real-world application,
however, the attainable overall accuracyof the rotary axis is affected by mounting
errors in the scale drum or scanning head,and by the guideway accuracy of the
bearing under different loads. Within theoverall very high accuracy of modular angle
encoders from HEIDENHAIN, theseexternal errors make up most of the error.
In some cases, it is therefore necessary
to perform accuracy compensation for therotary axis in order to meet requirements.
This can be done via two different
methods:• Dynamic compensation: This method
enables the continuous, dynamic
compensation of certain error
components of the overall angular error
during operation. It is particularly well
suited for sources of error that changeover time or under varying loads.
• Static compensation: This method
allows the angular error to becompensated for at a certain point intime and during a certain operating state.
It is especially well suited for constanterrors.

Dynamic compensation
Aids

Compensatable causes for angular error

Two scanning heads

Centering error during mounting
Radial runout error caused by bearing error
Load-dependent radial runout error of the bearing

More than two
scanning heads

In addition: graduation errors
For scale-tape systems; in addition, runout errors of
the scale-tape slot

Static compensation
Aids

Compensatable causes for angular error

Comparator system(ISO 230-2) or virtualreferenceCentering error during mounting

Comparator system(ISO 230-2)

Graduation error of the encoder Recommended for scale-tape encoders

CNC
NC program
Test program

PC
ACCOM
Test program

The following conditions are required for
dynamic compensation:• Two scanning heads that are mounted
opposite each other.
• The possibility of calculating thepositions of the scanning heads in realtime. For the ERA and ERM incremental
encoders, HEIDENHAIN offers the
EIB 15xx. For position calculation with
the ECA and ECM encoders, thecontroller manufacturers provide
solutions integrated directly into thecontroller software.
• For scale-tape encoders with very wide
diameters, such as those used intelescopes, four or more scanning heads
are often used. In this case, position
calculation occurs individually inaccordance with the use case and theconfiguration of the scanning heads.
Good static compensation requires asuitable standard for comparison. There are
two general approaches:• Use of an additional calibrated encoderwith higher accuracy and higher
reproducibility (e.g., RVM 4000) andcalibration of the rotary axis inaccordance with ISO 230-2. The
calculated compensation values arethen stored in the controller.
• Use of a virtual reference based on theencoder to be calibrated, aided by anadditional scanning head, an appropriate
evaluation unit (e.g., the PWM 21) and asoftware application from HEIDENHAIN.
The compensation values can be stored
directly in the scanning head. Thismethod is available only for selected
HEIDENHAIN encoders. This isbeneficial, for example, if compensation
is to occur at the component level andnot in a fully assembled machine.

ERA/ERM
Compensation via position calculation (e.g., the EIB 1500)

2x PWM21
21
2 x PWM

ECA
ECA
Compensation via a virtual reference with the PWM 21
Compensation via comparator system (e.g., RVM 4000)

20

21

Reliability

The modular angle encoders from
HEIDENHAIN are optimized for use in
fast and precise machines. Even with
their exposed mechanical design, theseencoders are highly immune tocontamination, ensure high long-term
stability and are fast and easy to mount.

The large scanning field further reduces
the sensitivity to contamination.
Depending on the nature of thecontamination, this feature can evenprevent encoder failure. The encoders
continue to provide high-quality signals
even if the contamination comes fromprinter’s ink, PCB dust, water or oil and is
up to 3 mm in diameter. The interpolation
error within one revolution remains far
below the specified accuracy.
The figures at right show the results ofcontamination tests with the ERA 4000.
The maximum interpolation errors within
one signal period |u| are shown. Despite
significant contamination, the specified
value of ±1% is only minimally exceeded.

2.5
2

Signal period 
Fingerprint contamination

In the METALLUR process, a reflective
gold layer is covered with a thin layer ofglass. On this layer are lines of translucent,light-absorbing chrome only several
nanometers in thickness. Measuring
standards with METALLUR graduations
have proven to be particularly robust andinsensitive to contamination because thelow height of the structure leaves practicallyno surface for dust, dirt or water particles
to accumulate.

Semi-transparent layer
Transparent layer

Reflective primary layer
Design of a METALLUR graduation

In the MAGNODUR process, alternating
north and south poles are created on the
periphery. Because the graduation lies
within the material, contamination on thescale drum has no effect on the signals.
This measuring standard becomesdamaged only if it comes into directcontact with a magnetic field (e.g., via atool).

2.5
2Signal period 
Toner dust contamination

Signal amplitude in % Magnetic encoders from HEIDENHAIN are
fully immune to this contamination test.
The measurement signal remains
unaffected even under continuous andsurrounding contamination. However,metal chips, for example, must be kept outof the cooling lubricant because they could
physically damage the cover sheet of thescanning head.

Application-oriented mounting
tolerances
The mounting tolerances of modular angle
encoders from HEIDENHAIN have minimal
influence on the output signals. In particular,a variation in the scanning gap between
the graduation carrier and scanning headcauses only negligible change in the signal
amplitude, and barely affects theinterpolation error within one signal period.
This behavior is substantially responsible
for the high reliability of angle encoders
from HEIDENHAIN.

2.5
2

150%

Magnetoresistive scanning principle

Approx. 200 µm
Approx. 400 µm
Approx. 1000 µm

100%

50%

Change in scanning gap in µm 

Nominal scanning gap (set with a spacer shim)
Signal amplitude in % 

Low sensitivity to contamination
Both the high quality of the grating and thescanning method are responsible for theaccuracy and reliability of the encoders.
These optical encoders from HEIDENHAIN
use single-field scanning, by which only
one scanning field is used to generated thescanning signals. Local contamination on
the measuring standard (e.g., fingerprints
or oil residue) influence both the lightintensity of the signal components and thequality of the scanning signals. The output
signals thereby change in amplitude but
not with regard to the offset and phase
position. They remain highly interpolable,
and the interpolation error within one signal
period remains low.

Durable measuring standards
Due to their exposed design, themeasuring standards of modular angle
encoders with optical scanning are lessprotected from their environment. For thisreason, HEIDENHAIN always uses robust
graduations manufactured in special
processes.

-20

-15

-10

-5

0

5

10

15

20

Change in scanning gap in µm 

Signal period 
Water droplet contamination

22

Typical relationship between the signal amplitude and thescanning gap (mounting clearance) for the ECM/ERM 2000

Influence of the scanning gap on the signal amplitude for the ERA 4000

23

Angle encoders on direct-drive motors

Direct-drive motors are increasingly being
used on rotary axes in order, for example,
to boost efficiency by increasing theattainable dynamic performance of theaxis motion.

Mechanical design types and mounting
Mounting support, functional testing and diagnostics

Positioncontroller

HEIDENHAIN provides various aids for
ensuring easy and optimal initial setup of
the modular angle encoder.

Speed
controller

Of particular importance for the
performance of a direct-drive feed axis
is the choice of encoder.

The position feedback from the angle encoder is used as the input for the
position controller and speed controller

Mounting support with the PWM 21
The ERA, ECA and ECM encoders, inconjunction with the PWM 21, offer
special, device-specific processes in order
to simplify and check for proper mounting.
The ATS software guides users throughthe necessary individual steps for, say,evaluating the signal quality. It also provides
notification if the recommended limit
values are not attained.

∆xn+1

Error in the calculated speed

Mounting support for the ERA 4000 with the ATS software and PWM 21

For incremental encoders, this includes theevaluation of the signal amplitudes, as wellas the reference mark position and width.
For absolute encoders, evaluation is
performed based on valuation numbers
and alarms.

∆t
Signal periodv = ∆x / ∆t

The speed v is calculated from the distance x travelled in a time intervalt (v = x/t). Position errors within one signal period cause the calculated
speed to fluctuate despite constant motion. (xn/t)  (xn+1/t)

Functional testing with the PWT 101
and PWM 21
The PWT 101 and the PWM 21 with the
ATS software provide basic functions for all
angle encoders. In the case of incremental
encoders, for example, the signal quality
can be evaluated. Function reserves,
warnings and alarms can be output for
absolute encoders.

Mounting support, such as for the ECM 2000 with the PWM 21 andATS software

Diagnostics in the control loop
The ECA and ECM absolute encoders
transmit valuation numbers to thedownstream electronics, thereby enabling
diagnostics for the encoders status or
determination of the function reserve,
including directly within the control loop at
the controller. The scaling is the same for
all HEIDENHAIN encoders and is stated asa function reserve (from 0% to 100%).

Motor current in A 

Limitation in the signal quality of theencoder or the resolution/number of signal
periods may cause:• Increased noise in the motor current andthereby higher power loss and motor
heating• High-frequency noise in the drive train• Reduced dynamic performance due tothe required reduction in gain factors
within the position and speed control
loops.

Angle encoder∆xn

The higher the speed-stability requirements,
particularly at low shaft speeds, the more
important are the following factors:• The signal quality of the encoder,meaning the lowest possible position
error within one signal period• The number of signal periods (withincremental encoders) and the resolution(with absolute encoders)

Motor

Position error 

The position and speed feedback of directdrive motors is achieved with a position
encoder. Angle encoder selection must
therefore be made on the basis of its
usage in the machine:

Mechanical mounting
High-quality physical mounting withintolerance is essential for ensuring the highreliability of the angle encoder. Please
follow the mounting instructions.

Functionality check, such as for the ERM 2000 with the PWT 101

0

100

200

300

400

500

Shaft speed in rpm 
Example of the noise behavior of optical and non-optical angle encoders inrotary tables with a direct-drive motor at a continuously increasing shaft
speed
Optical angle encoder with 32 768 lines
Optical angle encoder with 16 384 lines
Non-optical angle encoder with 2600 lines

24

25

Centering the scale drum

Signal-quality indicator for the ERA 4000
The ERA 4000 angle encoders feature a
built-in signal-quality indicator in the form ofa multicolor LED, permitting fast and easy
signal-quality checks during operation.

LED indicator for incremental signals

This feature provides a number of benefits:• Scanning-signal quality visualization
through a multicolor LED• Continuous monitoring of incremental
signals over the entire measuring length• Indication of reference-mark signal
behavior• Quick signal-quality checks in the field
without additional aids
The built-in signal-quality indicator permits
both a reliable assessment of theincremental signals and inspection of thereference mark signal. The quality of theincremental signals is indicated by arange of colors, permitting quite detailed
signal-quality differentiation. The tolerance
conformity of the reference mark signal isshown by means of a pass/fail indicator.

LED color

Quality of thescanning signals

Optimal



Good



AcceptableUnsatisfactory

LED indicator for the referencemark signal(functional check)
When the reference mark is traversed, theLED briefly lights up in red or blue: Out of tolerance In tolerance

ERA 4000: Signal-quality indicatorin the scanning head

Test film for magnetic graduation for
the ECM/ERM 2000
The test film makes magnetic polarity
visible. It is ideal for simple inspection inorder to detect and prevent damage to thegraduation:• Damage to the magnetic graduation(e.g., demagnetization via a tool)• Residual magnetism of the tool or screwprior to mounting

The modular angle encoders are made up
of a scanning head and a graduation carrier.
The graduation may be implemented in theform of a scale drum or a scale tape. The
position of the scanning head andgraduation relative to each other isdetermined solely via the machineguideway. For this reason, the machinemust be designed from the very beginning
to meet the following prerequisites:• The bearing must be designed such thatit meets the accuracy requirements of
the axis and the scanning-gap tolerancesof the encoder, even during operation(see the Technical data).
• The mounting surface for thegraduation carrier must meet theflatness, roundness, radial runout anddiameter requirements of the given
encoder.
• To facilitate adjustment of the scanninghead relative to the graduation, thescanning head should be fastened via a
mounting bracket or via appropriate fixed
stops.

Centering the graduation
Since graduations from HEIDENHAIN
have a very high degree of accuracy, theattainable overall accuracy is predominantly
affected by mounting errors (mainly
eccentricity errors). Various possibilities forcentering, depending on the encoder andmounting method, are possible forminimizing the eccentricity errors inpractice.

All modular angle encoders with scanningdrums are designed such that the
specified accuracy can be reached in theactual application. The mounting designs
ensure the highest possible reproducibility.

3. Centering with two scanning heads
This method is suitable for all modular
angle encoders with optical or magnetic
scanning and solid graduation carriers.
Because HEIDENHAIN graduations exhibit
a long-range characteristic error, andbecause the graduation or the position
value itself serves as the reference withthis centering method, this is the mostaccurate centering method.

1. Centering collar
The graduation carrier is pressed or shrunk
onto the shaft. This very simple method,
however, requires a highly exact shaft
geometry.

0
–e µm

+e µm

Centering via a centering collar

2. Three-point centering
The graduation carrier is centered via threepositions marked on the graduation carrierat 120° increments. As a result, anyroundness errors of the surface on which
the carrier is to be centered do not affectthe exact alignment of the axis center
point.

Ⓜ = Marking for three-point centeringⓈ = E.g., a capacitive sensor
Three-point centering for the ERA

Centering with two scanning heads

Visible marking on the test film after contact with an Allen wrench, as anindicator of tool magnetization

26

Scanning heads
Because the modular angle encoders aremounting at the machine, exact mountingof the scanning head is required after
mounting of the graduation carrier. In orderfor the scanning head to be exactly aligned,
it must in principle be aligned andadjustable in five axes (see illustration).
This adjustment is greatly facilitated by
the design of the scanning heads, withthe corresponding mounting strategy andwide mounting tolerances.

27

ERA 4000 and ECA 4000 series

The ERA 4000 and ECA 4000 modular
angle encoders consist of a scale drum anda scanning head. The scale drums areavailable in versions with a centering collar
and with three-point centering.
The ERA 4x80 versions are available withvarious grating periods depending on theaccuracy requirements. The appropriate
scanning heads for the scale drums areshown in the table at the right. Be sure thatthe diameters or number of signal periodsof the scale drum and scanning headmatch. Protecting the ERA and ECA series
encoders from contamination requires
special design measures. The ERA 4480
angle encoders can be delivered with anadditional sealing-air cover for various scale
drum diameters. This requires a special
scanning head (with a compressed-air
inlet). When ordering the sealing-air cover,be sure that it matches the drum diameter.

Scale-drum design

Centering methods Model ofscale drum

With centering collar • Slid or heat-shrunk TTR ERA 4200
onto shaft• Centering on the TTR ERA 4400
inner ring
TTR ERA 4800

AK ERA 4280

TTR ECA 4400

AK ECA 4410
AK ECA 4490

TTR ERA 4202

AK ERA 4280

TTR ECA 4402

AK ECA 4410
AK ECA 4490

With three-point
centering• Centering along
the outer ring

AK ERA 4880

Mounting tool

Mounting the scanning head for the ECA 4000/ERA 4000

The scale drum and the scanning unit are
mounted as described above. The separate
spacer shim supplied with the sealing-air
cover is laid around the scale drum. It
protects the scale drum during mountingof the sealing-air cover and ensures aneven scanning gap. The sealing-air cover isthen pressed onto the scale drum andfastened. The spacer shim is removed. For
information about the compressed-air inlet,
see General mechanical information.

Mounting the ERA 4x00/ECA 4400
scale drums
The scale drum is centered along its innerring via the centering collar. Two centering
methods are possible:a) The scale drum is pressed onto the drive
shaft or thermally shrunk (see also the
Functional Safety section) and fastenedwith screws. Adjustment of the drum istherefore unnecessary and impossible.
The scale drums can and should beheated for assembly. Back-off threads areprovided for disassembly.
b) The scale drums are centered along theirinner ring via the centering collar.

28

AK ERA 4480

Mounting the scanning head
In order for the scanning head to be
mounted, a mounting aid is placed
between the outer curved surface of thescale drum and the scanning head. The
scanning head is pressed against it andthen fastened. The shim or mounting aid isthen removed.

Mounting the sealing-air coverSome variants of the ERA 4000 angle
encoders are optionally available withsealing-air covers. This cover provides
additional protection from contamination
when compressed air is applied.

Special design features of the ERA andECA modular angular encoders assurecomparatively fast mounting and easy
adjustment.

Mounting the ERA 4202/ECA 4402
scale drums
The scale drums are centered via threepositions at 120° increments on their outercircumference and fastened with screws.
The benefits of three-point centering andthe solid scale-drum design make itpossible to attain very high accuracy whenthe encoder is mounted, with relatively
little mounting effort. The positions forcentering are marked on the scale drum.
Centering via the inner ring is not possible.

Appropriate
scanning headSpacer shim

Sealing-air coverCompressed-air inlet

Spacer shim

① = Centering collar② = Marks for drum centering (3 x 120°)

Mounting the scale drums

Mounting an ERA 4480 with sealing-air cover

Along with the encoder-specific centering
methods, centering with two scanningheads is possible as well.

29

ERM 2000 and ECM 2000 series

The ECM and ERM modular angle
encoders consist of a scale drum and ascanning head. This design of the ECM
and ERM series enables relatively fast
mounting without adjustment work.
The ERM scale drums are available in three
versions. The main difference between
them is their mounting method. All of thescale drums feature a centering collar on
the inner ring.
Mounting the TTR ERM 2200,
TTR ERM 2203, TTR ERM 2400
and TTR ECM 2400 scale drums
The scale drum is centered along its innerring via the centering collar. Two centering
methods are possible:a) The graduation drum is pressed onto themating shaft or thermally shrunk (seealso the Functional Safety section) andfastened with screws. Adjustment of thedrum is therefore unnecessary andimpossible. The scale drums can andshould be heated for assembly.
b) The scale drums are centered along theirinner ring via the centering collar.

Mounting the TTR ERM 2x00
scale drums
The TTR ERM 2404 and TTR ERM 2904
scale drums are clamped to the bearing
surface solely via a friction-locked
connection. How the scale drum isclamped depends on the mounting
situation.
The clamping force must be applied
circularly over the plane surface of thedrum. The necessary mounting elements
depend on the design of the customer’sequipment and are therefore theresponsibility of the customer. The frictional
connection must be strong enough toprevent unintentional rotation or skewing inaxial and radial directions, even at highshaft speeds and accelerations.

Mounting the TTR ERM 2405
scale drums
The TTR ERM 2405 scale drums areprovided with a keyway. The keyway may
be used solely as an anti-rotation element
and not for transmitting torque. The special
inner shape of the drum for this version
also ensures durability even at the highest
permissible shaft speeds.

Designing the mounting elements
For designing the mounting elements, use
the following parameters of the scale
drum:

Mounting the scanning head
In order for the scanning head to be
mounted, the provided spacer shim is laidon the outer curved surface of the scale
drum. The scanning head is pressedagainst the shim and fastened. The shim isthen removed. The scanning heads areavailable with different cable outlets.
Protection form damage due tomagnetic fields
During mounting, ensure that neither theouter curved surface of the scale drum nor
the scanning area comes into contact withmagnetic fields (e.g., of tools). The use ofnon-magnetizable tools is recommended.
Magnetic field intensities that typicallyarise during operation (e.g., in theimmediate vicinity of motors) do not haveany negative effects on the ERM or ECM
encoders.

Test film for magnetic graduation
A test film can be used to make themagnetic graduation visible. It enables theuser to easily check whether there is any
damage to the magnetic graduation, suchas demagnetization from a tool. The test
film can also be used prior to mounting forchecking the tool or screws for residual
magnetization in order to prevent damage
to the graduation. The test film can be“cleaned” with the aid of a demagnetization
device and therefore used repeatedly. The
test film and demagnetization device areavailable as accessories.

Permissible surface pressure:pzul = 100 N/mm2
Coefficient of thermal expansion:Þtherm = 10 · 10–6 K–1
Average surface roughness of the front
mating surfaces:
RZ  8	For scale drums with an outside
diameter < 326.9 mm
RZ  16	For scale drums with an outside
diameter  326.9 mm

Handling information

HEIDENHAIN

TTR
ER
M

24

00

Tangential, to the rightN

HEIDENHAIN

HEID
EN
HA
I

Tangential, to the left

HEIDENHAIN

Axially

Mounting the scale drum
TTR ERM 2400
TTR ERM 2200
TTR ERM 2203
TTR ECM 2400

30

Mounting the scale drum
TTR ERM 2404
TTR ERM 2904

Mounting the scale drum
TTR ERM 2405

Possible cable outlets

Mounting the scanning head (e.g., AK ERM 2480)

31

ERA 7000 and ERA 8000 series

The ERA 7000 and ERA 8000 series angle
encoders consist of a scanning unit and asingle-piece steel scale tape. The steel
scale tape is available in lengths of up to
30 m.
The tape is mounted on• the inner ring (ERA 7000 series)• the outer ring (ERA 8000 series)
of a machine element.

Mounting the scale tape for full-circle
applications

The ERA 74x0 C and ERA 84x0 C angle
encoders are designed for full-circle
applications. They are therefore ideal forhollow shafts with large inside diameters(approx. 400 mm or larger) and to
applications requiring accurate
measurement over a large circumference(e.g., large rotary tables, telescopes).

ERA 84x0 C: The scale tape is suppliedwith the halves of the tensioning cleat
already mounted to the tape ends. An
external slot is necessary for mounting,and a recess is required for the tensioning
cleat. After the scale tape has been
inserted, it is pushed up against the slotedge and tensioned there with thetensioning cleat.

For applications where there is no fullcircle, or measurement is not required over
360°, segment solutions are available.

Determining the mating diameter
In order to ensure correct functioning of
the distance-coded reference marks, thecircumference must be a multiple of 1000
grating periods. The relationship between
the mating diameter and the signal period
can be seen in the table.

ERA 74x0 C: An internal slot with a
specified diameter is required for receiving
the scale tape. The scale tape is inserted
starting at the butt joint and is clicked into
the slot. The length is cut so that the tapeis held in place by its own force.

Determining the segment angle
For segment solutions, the angle available
as the measuring range must be a multipleof 1000 grating periods. Also, thecircumference of the theoretical full circle
must be a multiple of 1000 grating periods,
since this often simplifies integration with
the numerical control.
Mounting the scanning head
For mounting the scanning head, thespacer shim is held against the outercurved surface of the scale drum. The
scanning head is pressed against the shim
and fastened. The shim is then removed. In
addition, the scanning field can be finely
adjusted via an eccentric bushing.

The scale tape ends are manufactured soexactly that only slight angular and signalshape errors may occur in the area of thebutt joint. To ensure that the scale tapedoes not move within the slot, it is
attached near the butt joint with dots ofadhesive.

ERA 84x1 C: The scale tape is delivered
with pre-mounted end pieces. An external
slot with recesses for the end pieces isrequired in order to accommodate thescale tape. The end pieces are fitted withtension springs that ensure optimal
preloading of the scale tape and evenly
distribute expansion along the entire scaletape length.

Measuring range in degrees
for segment solutions

ERA 7000 C

n · 0.01273112 +0.3

n1 · 4.583204 : (D–0.3)

ERA 8000 C

n · 0.0127337 –0.3

n1 · 4.584121 : (D+0.3)

n = Signal period of full circle; n1 = Signal period of measuring range
D = Mating diameter [mm]Measuring range
Mating diameter

Theoretical full circle

Checking the output signals at the butt
joint
In order to check whether the scale tapesof the ERA 74x0 C and ERA 84x0 C havebeen mounted correctly, the output signals
should be checked at the butt joint before
the adhesive has hardened.

Mounting the scale tape for segment
solutions
ERA 74x1 C: An internal slot with a
specified diameter is required in order toaccommodate the scale tape. The two cam
disks mounted in this slot are adjusted sothat the scale can be pressed into the slot
under tension.

Mating diameter in mm

Spacer shim

The quality of the output signals can bechecked using a PWT phase-angle testing
unit from HEIDENHAIN. When thescanning head is moved along the scaletape, the PWT graphically displays thesignal quality and the reference markposition.

Cam disks

Spring

The PWM 9 phase-angle measuring unit
quantatively displays deviations of theoutput signals from the ideal signal (seeHEIDENHAIN measuring and testing
devices).

PWT

ERA 84x2 C: To accommodate the scaletape, an external slot or a single axial edge
is recommended. The scale tape is
supplied without tensioning elements. It
must be preloaded with a spring balanceand screw-fastened at the two oblong
holes.

32

33

General information

Protection
Modular angle encoders with opticalscanning must be protected fromparticulate and liquid contamination in theapplication. Suitable encapsulation bymeans of seals and sealing air may benecessary.
The scanning heads themselves partially
fulfill the IP40 (ERA) and IP67 (ECA)
protection rating in accordance with
EN 60529 and IEC 60529.
Optional sealing-air covers are available forseveral variants of the ERA 4000 angle
encoders, permitting a protection rating
increase to IP40. Connection to a source ofcompressed air slightly above atmosphericpressure provides additional protection
against condensation. The sealing-air cover
is not designed to provide protection fromliquid or dust contamination. In many
applications, however, the sealing-air coverprovides reliable protection. Design-related
constraints and operating conditions have adecisive influence.

Accessory:
DA 400 compressed air unit
ID 894602-01
DA 400HEIDENHAIN offers the DA 400
compressed-air filter system for purifying
the compressed air. It is designed
specifically for connecting compressed air
to encoders.
The DA 400 consists of three filter stages(prefilter, microfilter and activated carbon
filter) and a pressure regulator with amanometer. The sealing air function can beeffectively monitored using a manometerand pressure switch (available as anaccessory).

The compressed air introduced into the
DA 400 must fulfill the requirements of thefollowing purity classes as per ISO 8573-1(2010 edition):• Solid contaminants:
Particle size

Class 5
No. of particles
per m30.1 µm to 0.5 µm
Not specified
0.5 µm to 1.0 µm
Not specified
1.0 µm to 5.0 µm
 100 000
• Max. pressure dew point: Class 6(pressure dew point at 10 °C)• Total oil content:
Class 4(max. oil concentration 5 mg/m3)

Further information:
For more information, please request
our DA 400 Product Information.

At a pressure of approx. 1 · 105 Pa (1 bar),the HEIDENHAIN connecting piece with an
integrated air inlet ensure a flow rate of
approx. 33 liters/rpm. This configuration
provides good protection from dust in mostcases.

Temperature range
The operating temperature range
indicates the ambient temperature limits
between which the angle encoders willfunction properly.
The storage temperature range applies tothe device within its packaging (ERA/ECA:–20 °C to 70 °C, ERM/ECM: –30 °C to
70 °C).
Protection from contact
After installation of the encoder, all rotatingparts must be protected from accidental
contact during operation.
Acceleration
Angle encoders are subject to various
types of acceleration during operation andinstallation.
• The indicated maximum values forvibration resistance are valid inaccordance with EN 60068-2-6.
• The maximum values for the permissible
acceleration (sinusoidal shock) for shock
and impact loads apply at 6 ms
(EN 60068-2-27). Impacts or jarring witha hammer, such as in order to align theencoder, are never permitted.

A proven method of avoiding contamination
under difficult ambient conditions, bothduring operation and at standstill, is toadequately cover the area where theencoder is installed (in addition to thesealing-air cover) and flush it with clean
compressed air, or to generate slightoverpressure.
The compressed air entering the encoder
must be purified by a microfilter andcomply with the following quality classes
as per ISO 8573-1 (2010 edition):• Solid contaminants:
Class 1
Particle size
No. of particles
per m30.1 µm to 0.5 µm
 20 000
0.5 µm to 1.0 µm
 400
1.0 µm to 5.0 µm
 10• Max. pressure dew point: Class 4(pressure dew point at 3 °C)• Total oil content:
Class 1
(max. oil concentration: 0.01 mg/m3)

34

Shaft speeds
The maximum permissible shaft speeds
were determined in accordance with the
FKM guideline. This guideline serves as amathematical attestation of component
strength with regard to all relevant
influences, and it reflects the current stateof the art. The requirements for fatigue
strength (107 million reversals of load)
were considered in the calculation of
the permissible shaft speeds. Because
installation has a significant influence,
all requirements and directions in thespecifications and mounting instructions
must be followed in order for the shaftspeed data to be valid.
RoHSHEIDENHAIN has tested its products toensure the use of non-hazardous materials
in accordance with the European Directives
2002/95/EC (RoHS) and 2002/96/EC(WEEE). For a Manufacturer’s Declaration
on RoHS, please consult your sales agency.
Parts subject to wear
Encoders from HEIDENHAIN are designed
for a long service life. Preventive
maintenance is not required. However,they do contain components that are
subject to wear, depending on theapplication and how they are deployed.
This especially applies to cables that are
subject to frequent flexing.

System tests
Encoders from HEIDENHAIN are usually
integrated as components into complete
systems. Such applications requirecomprehensive testing of the entire
system, irrespective of the encoder’sspecifications.
The specifications provided in thisbrochure apply only to the encoder andnot to the entire system. Any operationof the encoder outside of the specified
range or outside of its proper andintended use is at the user’s own risk.
In safety-related systems, the encoder’sposition value must be tested by thehigher-level system after switch-on.
Mounting
The steps and dimensions that must becomplied with during mounting are
specified solely in the mounting
instructions supplied with the device.
All mounting-related information in thisbrochure is therefore provisional and nonbinding, and will not become the subject
matter of a contract.

EN 60529

DA 400Protection from contact

35

Functional safety

Safe axes
Driven axes on machine tools usually posea significant hazard for humans. Particularly
when the human interacts with the machine(e.g., during workpiece setup), it must be
ensured that the machine tool does notmake any uncontrolled movements. Here,the position information of the axes isneeded in order to implement a safetyfunction. As an evaluating safety module,
the controller detects faulty position
information and reacts to it accordingly.
Various safety strategies can be pursued,
depending on the topology of the axis andthe evaluation capabilities of the controller.
In a single-encoder system, for example,
only one encoder per axis is evaluated forthe safety function. However, on axes withtwo encoders, such as a rotational axis
with a rotary encoder and an angle
encoder, the two redundant position values
can be compared with each other in thecontroller.

Safety-related fault detection can beensured only if the two components, thecontroller and the encoder, are properly
matched to each other. In this case, it must
be noted that the safety designs may varyby controller manufacturer. This also meansthat the requirements placed on theconnected encoders may differ.
Type-examined encoders
Modular angle encoders from HEIDENHAIN
thrive in a wide variety of safety designs
with a variety of controllers. Particularly
noteworthy are the type-examined
ECA 4410 and ECM 2410 encoders with
the EnDat interface. These encoders canbe operated as single-encoder systems inconjunction with a suitable controller inapplications with the controller category
SIL 2 (as per EN 61508) or performancelevel “d” (as per EN ISO 13849). Unlike
incremental encoders, the ECA 4410/
ECM 2410 absolute angle encoders always
provide a safe absolute position value,
including immediately after switch-on ora power failure. The reliable transmission of
the position is based on two independently
generated absolute position values and on
error bits provided to the safe controller.
The purely serial data transmission alsooffers other advantages, such as greater
reliability, improved accuracy, diagnostic
capabilities and reduced costs throughsimpler connection technology.
Standard encoders
In addition to those encoders explicitly
certified for safety applications, standard
angle encoders can also be used in safe
axes (e.g., with 1 VPP signals or Fanucinterface). In this case, the characteristicsof the encoders must be matched to therequirements of the respective controller.
HEIDENHAIN can provide additional data
about the individual encoders (failure rate,
fault model as per EN 61800-5-2).
Service life
Unless otherwise specified, HEIDENHAIN
encoders are designed for a service life of
20 years (in accordance with ISO 13849).

Further information:

Fault exclusion for the loosening of themechanical connection
Irrespective of the interface, many safety
designs require the safe mechanicalconnection of the encoder. The standard
for electric motors, EN 61800-5-2, requiresthat the loosening of the mechanicalconnection between the encoder and the
motor be considered as a fault. Because
the controller may not be able to detect
these errors, fault exclusion is required inmany cases.
This mechanical fault exclusion has beencertified for a wide range of encoder
applications. This means that the fault
exclusion is ensured for the operating
conditions listed below.

Mechanical connection

Upon request, HEIDENHAIN can also
provide additional data about theindividual products (failure rate, fault
model as per EN 61800-5-2) for the useof standard encoders in safety-related
applications.

Safe encoder

Fault exclusion for scanning heads andscale drums
There are various mounting possibilities forthe scanning heads that offer fault exclusion
for the loosening of the mechanicalconnection. The fault exclusions apply
to all scanning heads, regardless of theinterface. Among the scale drums,
the TTR ECA 4400, TTR ERA 4x00,
TTR ECM 2400, TTR ERM 2x00 and
TTR ERM 2203 scale drum types provide
fault exclusion for the loosening of themechanical connection. If no mechanicalfault exclusion is required for the safety
design, then the scale drum can bemounted without a press-fit.

Mechanical connection

Fastening

Safe position for themechanical coupling3)

Constrained characteristic
values4)

ERA
ECA

Scale drum

Press-fit as per dimension drawing
Screw connection:1) 2)
ISO 4762-M5x20-8.8 screws
ISO 4762-M6x25-8.8 screws

Drum outside diameter
104.63 mm to 127.64 mm:±0.025°

Scanning head

Mounting type I:
Screw connection:2)
ISO 4762-M3x25-8.8 screws

See Specifications:• Vibration (possibly)• Shock• Maximum angularacceleration• Operating temperature

The safety-related characteristic values
are listed in the encoder specifications.
The Technical Information document
Safety-Related Position Encoders
provides explanations about thecharacteristic values.

Electrical connection

The requirements for fault exclusion
can result in additional constraints inthe permissible limit values in thespecifications. In addition, fault exclusions
for the loosening of the mechanical coupling
usually require additional measures during
installation of the encoder or in the eventof servicing (e.g., anti-rotation lock forscrews). These factors must be considered
for the selection of a suitable encoder andmounting method.

Drum outside diameter
148.2 mm or larger:±0.0°

Mounting type II:
Screw connection:2)
M3x20 ISO 4762 8.8 screws
ERM
ECM

Scale drum

Press-fit as per dimension drawing(W2)
Screw connection:2)
M5 ISO 4762 8.8 screws

Scanning head

Screw connection:
M4 ISO 4762 8.8 screws

Safe controller±0.025°

See Dimensions:• Mounting tolerances• Mating dimensions
See Mounting information:• Material• Mounting conditions

2)

1)

A material bonding anti-rotation lock must be used for the screw connections of the scale drums (mounting/servicing)
Friction Class B as per VDI 2230
3)
Fault exclusions exist only for the explicitly stated mounting conditions
4)
Unlike the ECA/ERA 4xxx and ECM/ERM 2xxx, without mechanical fault exclusion
2)

Safety-related position
measuring system

Encoder with mechanical connection and electrical interface

36

37

During shrink-fitting, make sure that thehole patterns of the scale drum and mating
shaft are properly aligned. Appropriate
centering aids (setscrews) can facilitate
mounting. All of the mounting screws
must be retightened at the correct torqueafter the scale drum has cooled. The
mounting screws used for attaching thescanning head and scale drum may be
used only to secure the scanning head andthe scale drum. These screws may not be
used to additionally fasten othercomponents.

Mounting the scale drum
A press-fit of the scale drum on the shaft isrequired for fault exclusion. Preferably, thescale drum should be thermally shrunk
onto the mating shaft and fastened withscrews. For this purpose, the scale drum
must be slowly heated prior to mounting,such as with a heating plate (caution: do
not use induction heating sources). The
diagram shows the recommended
minimum temperatures for the different
drum diameters. The maximum
temperature must not exceed 140 °C.

Removing the scale drum
The scale drum is removed using therelevant back-off threads in the drum. To dothis, insert greased screws, and tighten
them in a row until the scale drum comes
off the shaft. Prior to renewed mounting of
the scale drum, the back-off threads must
be recut.

Material
For the mating shaft and the mating stator,
use materials in accordance with the table.
Mounting temperature
All information on screw connections isbased on a mounting temperature of 15 °C
to 35 °C.

ERM/ECM
Mating shaft

Mating stator

Material

Steel

Steel/cast ironTensile strength Rm

 600 N/mm2

 250 N/mm2

Shear strength τm 390 N/mm2

 290 N/mm2

Elastic modulus E

 200 000 N/mm
to 215 000 N/mm2

Coefficient of thermal
expansion Þtherm(10 to 13) · 10–6 K–1 1)

Temperature in °C 

1)

Recommended minimum
fitting temperature* of the
ERA/ECA scale drum in °C

Max. permissible
temperature of thescale drum

Recommended minimum
fitting temperature* of the
ERM/ECM scale drum in °C

140
130
120
110

Mounting the scanning head
Ensure that the diameter specifications forall encoder components match (scale
drum, scanning head, mounting aid for
ERA/ECA). The relevant information isindicated on the ID labels. A mounting
wizard in the ATS software helps ensurethat the scanning head and the scale drum
are properly aligned.
Accessories:• Mounting aid for the ERA/ECA (as per
drum diameter)• Mounting wizard in ATS software

100
90
80
70

50

40

80

120

160

200

240

280

320

360

400

440

480

110 000 N/mm2
to 215 000 N/mm2

Others upon request

ERA/ECA
Mating shaft / Mating stator
Material

Steel

Tensile strength Rm

 600 N/mm2

Shear strength τm 390 N/mm2

Elastic modulus E

 200 000 N/mm
to 215 000 N/mm2

Coefficient of thermal
expansion Þtherm(10 to 13) · 10–6 K–1 1)

1)
60

2

2

Others upon request

520

Scale drum inside diameter in mm * The temperature values assume an ambient temperature of 22 °C.
If the ambient temperature deviates from this, then adjust the fitting temperature accordingly.

Further information:
Comply with the requirements described in the following documents to ensure correctand intended operation:• Mounting Instructions and possibly Operating Instructions of the given product
AK ECA 4410 Functional Safety			
1177157
TTR ECA 4400					1177156
TTR ECA 4402					1125430
Mounting assistant for the ECA 44xx		
1126455
AK ECM 2410/2490 M/2490 F			TTR ECM 2400					Mounting assistant for the ECM 24x0		3813083771308375
1356342• Technical Information: Safety-Related Position Measuring Systems

596632For implementation in a controller:• Specification for safe controller		

53309539

ECA 4400 series
Absolute angle encoder with high accuracy• Steel scale drums with three-point centering or centering collar• Consists of a scanning head and scale drum
• Also for safety-related applications• Mechanical fault exclusion for scanning heads and scale drum
With mechanical fault exclusion

ECA 4000

Scanning head

AK ECA 4410

Interface

AK ECA 4490 F

AK ECA 4490 M

AK ECA 4490 P

AK ECA 4490Y

EnDat 2.2

Fanuc SerialInterface;Þi Interface

Mitsubishi highspeed interface

Panasonic SerialInterface

Yaskawa SerialInterface

Ordering designation

EnDat22

Fanuc05

Mit03-4

Pana02

YEC07

Clock frequency

 16 MHz–

Calculation time tcal

 5 µs–Functional safety
for applications with up to–• SIL 2 as per EN 61508(other basis for testing:
IEC 61800-5-3)• Category 3, PL “d” as per
EN ISO 13849-1:2015

PFH–9 20 · 10 (up to 6000 m
above sea level)

Electrical connection

Cable (1 m or 3 m) with
8-pin M12 coupling (male) or 15-pin D-sub connector≤ 30 m≤ 50 m1)

AK ECA 4410–

≤ 50 mCable length 100 mSupply voltage

DC 3.6 V to 14 V

Power consumption (max.)

At 3.6 V: 700 mW
At 14 V: 800 mW

At 3.6 V: 850 mW
At 14 V: 950 mW

Current consumption (typical)

At 5 V:
90 mA(without load)

At 5 V:
100 mA(without load)

Vibration: 55 to 2000 Hz
Shock: 6 ms

 200 m/s2 (EN 60068-2-6)  500 m/s2 (EN 60068-2-6)
 200 m/s2 (EN 60068-2-27)  1000 m/s2 (EN 60068-2-27)

Operating temperature–10 °C to 70 °C

Protection EN 605293)

IP67

Mass			Scanning head				Cable
				M12 coupling				D-sub connector

18 g (without cable)
20 g/m
15 g
32 g

2)

–10 °C to 70 °C

1)With HEIDENHAIN cable; clock frequency  8 MHz
With a drum outside diameter of 104.63 mm: 10 °C to 70 °C
3)	In the application, the device must be protected from contamination by solids and liquids.
If necessary, use a suitable enclosure with sealing air and a seal
2)

40

41

Optionally with mechanical fault exclusion

Without mechanical fault exclusion

Scale drum

TTR ECA 4400

Scale drum

TTR ECA 4402

Measuring standard
Coefficient of expansion

Steel drum with centering collar–6 –1Þtherm  10.4 · 10 K

Measuring standard
Coefficient of expansion

Steel drum with three-point centering–6 –1
therm  10.4 · 10 K

Drum inside diameter*

70 mm

80 mm

120 mm

120 mm

150 mm

180 mm

270 mm

425 mm

512 mmDrum inside diameter*

70 mm

80 mm

130 mm

512 mm127.64
mm

148.2
mm

178.55mm

208.89mm

254.93mm

331.31mm

484.07mm

560.46mm

180 mm/
210 mm

425 mm104.63mm

150 mm/
185 mm

270 mmDrum outside diameter*

120 mm/
150 mmDrum outside diameter*

104.63mm

127.64mm

178.55mm

148.20mm

208.89mm

254.93mm

331.31mm

484.07mm

560.46mm

Mech. permissible speed

15 000rpm

12 250
rpm

8750
rpm

10 500
rpm

7500
rpm

6250
rpm

4750
rpm

3250
rpm

2750
rpm

Elec. permissible speed≤ 7000rpm≤ 5750rpm≤ 3000rpm≤ 4400rpm≤ 2550rpm≤ 2100rpm≤ 900 rpm ≤ 600 rpm ≤ 550 rpm

Moment of inertia

0.83 · 10–3 2.0 · 10–3
kgm2
kgm2

7.1 · 10–3
kgm2/
4.5 · 10–3
kgm2

1.7 · 10–3
kgm2

12 · 10–3
kgm2
6.5 · 10–3
kgm2

28 · 10–3
kgm2/
20 · 10–3
kgm2

59 · 10–3
kgm2

199 · 10–3 263 · 10–3
kgm2
kgm2

Safe position1) 2)±0.88°±0.44°±0.22°±0.11°

Safety-related
measuring step SM

0.352°(10 bits)

0.176°(11 bits)

0.088°(12 bits)

0.044°(13 bits)

Mech. permissible speed
With mechanicalfault exclusion

8500
rpm

6250
rpm

5250
rpm

4500
rpm

4250
rpm

3250
rpm

2500
rpm

1800
rpm

1500
rpm

Without mechanicalfault exclusion

15 000rpm

12 250rpm

10 500
rpm

8750
rpm

7500
rpm

6250
rpm

4750
rpm

3250
rpm

2750
rpm

Max. angular acceleration

14 000rad/s26600
rad/s27900
rad/s22700
rad/s21800
rad/s2

1000
rad/s21300
rad/s2900
rad/s2

1200
rad/s2

Elec. permissible speed

 7000rpm

 5750rpm

 4400rpm

 3000rpm

 2550rpm

 2100rpm

 900 rpm  600 rpm  550 rpm

Moment of inertia

0.81 · 10–3 1.9 · 10–3
kgm2
kgm2

2.3 · 10–3
kgm2

7.1 · 10–3
kgm2

12 · 10–3
kgm2

28 · 10–3
kgm2

59 · 10–3
kgm2

195 · 10–3 258 · 10–3
kgm2
kgm2

Permissible axial movement  ±0.4 mm (scale drum relative to the scanning head)

Permissible axial movement ≤ ±0.4 mm (scale drum relative to the scanning head)
Positions per revolution

134 217 728 (27 bits)

268 435 456 (28 bits)

536 870 912 (29 bits)

Measuring step

0.0097“

0.0048“

0.0024“Signal periods

8195

10 010

14 003

11 61616 37919 99825 99337 99444 000Accuracy of graduation

±3”

±2.5”

±2”

±2.3”

±1.9”

±1.8”

±1.7”

±1.5”

±1.5”

±0.20”±0.16”±0.12”±0.14”±0.10”±0.08”±0.06”±0.04”±0.04”

 1.5 kg/
 0.66 kg

 2.3 kg/ 1.5 kg

 2.6 kg

 3.8 kg

 3.7 kg

Positions per revolution

134 217 728 (27 bits)

268 435 456 (28 bits)

536 870 912 (29 bits)

Interpolation error per
signal period

Measuring step

0.0097“

0.0048“

0.0024“Protection EN 60529

Complete encoder after mounting: IP00

Signal periods

8195

10 01011 61614 00316 37919 99825 99337 99444 000Mass 0.42 kg

Accuracy of graduation

±3.7”

±3.0”

±2.8”

±2.5”

±2.5”

±2.5”

±2.5”

±2.0”

±2.0”

Interpolation error per
signal period±0.20”±0.16”±0.14”±0.12”±0.10”±0.08”±0.06”±0.04”±0.04”

 1.5 kg 2.3 kg

 2.6 kg

 3.8 kg

 3.6 kg3)

Protection EN 60529

Complete encoder after mounting: IP00

Mass

 0.40 kg

 0.68 kg 0.51 kg 1.2 kg1)

 0.69 kg 1.2 kg/
 0.66 kg 0.35 kg* Please select when ordering	In the application, the device must be protected from contamination by solids and liquids.
If necessary, use a suitable enclosure with a seal and sealing air

1)* Please select when ordering	Further deviations may arise in the downstream electronics after position value comparison (contact mfr. of the downstream
electronics)2)
Mechanical coupling: Fault exclusion for the loosening of the scanning head and scale drum, see Functional safety3)	In the application, the device must be protected from contamination by solids and liquids.
If necessary, use a suitable enclosure with a seal and sealing air
1)

42

43

ECA 4410, ECA 4490 (scale drum with centering collar)
Dimensions

> 11

> 16

Accessory: Mounting aid

> 60

>8

11

5a

5b

7b

7a

W1 = Without mechanical fault exclusion
W2 = With mechanical fault exclusion,  = Mounting possibilities
 = Bearing of mating shaft
W = Mating diameter (shaft)
1 = Roundness of mating diameter (shaft)
2 =	Permissible axial motion of measured
shaft: ≤ ±0.4 mm
3 = Proposed design for undercut
4 =	Back-off thread, not permitted for drum
fastening44

5 = Optical centerline
6 = Cable support
7a =	Positive direction of rotation for scanningheads with functional safety
7b =	Positive direction of rotation for scanningheads without functional safety
8 = Incremental track
9 = Absolute track
10 = Space for mounting aid
11 = Mounting aid

Further information:
For CAD data, visit cad.heidenhain.com

45

ECA 4412, ECA 4492 (scale drum without centering collar)
Dimensions

Accessory: Mounting aid
8±0.1
ISO 4762 - M3x25 - 8.8
ISO 7092 - 3 - 200HV>16

 W /  D1

4

ISO 4762 - M3x20 - 8.8



ISO 7092 - 6/5/3 - 200HV - 8.8>60

ISO 4762 - M6x22/M5x20/M3x20

3a

3b

4b

4a

,  = Mounting possibilities
 = Bearing
W = Mating diameter (shaft)
1 = Permissible axial motion of the motor shaft: ≤ ±0.4 mm
2 = Not permissible for drum fastening
3 = Optical center line and marking for 0° position
4a = Positive direction of rotation for scanning heads with functional safety
4b = Positive direction of rotation for scanning heads without functional safety
5 = Marking for drum centering (3x120°)
6 = Incremental track
7 = Absolute track
8 = Space for mounting aid
9 = Mounting aid

46

Further information:
For CAD data, visit cad.heidenhain.com

47

ERA 4000 series
High-accuracy incremental angle encoder• Steel scale drum with three-point centering or centering collar• Optimized scanning performance for very high reliability• Integrated three-color LED signal-quality indicator• Consists of a scanning head and scale drum with optional sealing-air cover
AK ERA 4280 with 20 µm graduation period
AK ERA 4480 with 40 µm graduation period
AK ERA 4880 with 80 µm graduation period

Scanning head

AK ERA 4470

Interface« TTL

Interface» 1 VPP, HSP

Integrated interpolation*

1-fold10-fold

50-fold

100-fold

500-fold

1000-foldCutoff frequency –3 dB

1 MHz

Scanning frequency2)

 450 kHz 312.5 kHz

 125 kHz 62.5 kHz 12.5 kHz

 6.25 kHz

Electrical connection

Cable (1 m or 3 m)
12-pin M12 coupling or 12-pin M23 coupling or 15-pin D-sub connector

Edge separation a 0.220 µs

 0.07 µs

 0.03 µs

Electrical connection*

Cable length 150 m (with HEIDENHAIN cable)

Cable (1 m or 3 m)
15-pin D-sub connector (male), with interface electronics in the connector

Supply voltage

DC 5 V ±0.5 V

Cable lengthWith HEIDENHAIN cable:  20 m; during signal adjustment with the PWM 21:  3 m

Current consumption< 130 mA (without load)

Supply voltage

DC 5 V ±0.5 V

Vibration 55 Hz to 2000 Hz

Current consumption

 250 mA (without load)

Shock 1
 1 ms
6 ms

With mechanical fault exclusion:  200 m/s2 (EN 60068-2-6)
Without mechanical fault exclusion:  200 m/s2 (EN 60068-2-6)
With mechanical fault exclusion:  200 m/s2 (EN 60068-2-27)
Without mechanical fault exclusion:  1000 m/s2 (EN 60068-2-27)

Vibration 55 Hz to 2000 Hz

Operating temperature–10 °C to 70 °C

Shock 11 ms
6 ms

With mechanical fault exclusion:  200 m/s2 (EN 60068-2-6)
Without mechanical fault exclusion:  200 m/s2 (EN 60068-2-6)
With mechanical fault exclusion:  200 m/s2 (EN 60068-2-27)
Without mechanical fault exclusion:  1000 m/s2 (EN 60068-2-27)

Relative air humidity

 93% (at 40 °C/4d as per EN 60068-2-78); condensation excluded

Operating temperature–10 °C to 70 °C

Protection

IP40

Relative air humidity

 93% (at 40 °C/4d as per EN 60068-2-78); condensation excluded

Mass		Scanning head
Connecting cable
Coupling (M12)
Coupling (M23)
D-sub connector

 20 g (without cable) 20 g/m
 15 g 50 g 32 gProtection

IP40

Mass	Scanning head
Cable
D-sub connector

 20 g (without cable) 20 g/m
 74 gScanning head

AK ERA 4480 with 40 µm graduation period and sealing-air coverInterface» 1 VPP, HSP

Cutoff frequency –3 dB

1 MHz

Electrical connection

Cable (1 m or 3 m)
12-pin M12 coupling or 12-pin M23 coupling

Cable length 150 m (with HEIDENHAIN cable)

Supply voltage

DC 5 V ±0.5 V

Current consumption< 130 mA (without load)

Vibration 55 Hz to 2000 Hz
Shock: 1 1 ms
6 ms

With mechanical fault exclusion:  200 m/s2 (EN 60068-2-6)
Without mechanical fault exclusion:  200 m/s2 (EN 60068-2-6)
With mechanical fault exclusion:  200 m/s2 (EN 60068-2-27)
Without mechanical fault exclusion:  1000 m/s2 (EN 60068-2-27)

Operating temperature–10 °C to 70 °C

Relative air humidity

 93% (at 40 °C/4d as per EN 60068-2-78); condensation excluded

Protection

IP40

Mass		Scanning head
Cable
Coupling (M12)
Coupling (M23) 35 g (without cable) 20 g/m
 15 g 50 gScanning head48

1)

* Please select when ordering1)	Suitable for applications that measure the time between individual TTL output signal clock edges;
non-clocked output signals enable low edge jitter2)
Maximum scanning frequency during referencing: 70 kHz

49

Scale drum with centering collar

TTR ERA 4200 C with 20 µm graduation period
TTR ERA 4400 C with 40 µm graduation period
TTR ERA 4800 C with 80 µm graduation period

Measuring standard
Coefficient of expansion

Steel drum
–6 –1
therm  10.4 · 10 K

TTR ERA 4200

12 000/±0.32”

16 384/±0.24”

20 000/±0.19”

28 000/±0.14”

32 768/±0.12”

40 000/±0.10”

52 000/±0.07”––TTR ERA 4400

6000/
±1.08“

8192/±0.79“

10 000/±0.65“

14 000/±0.46“

16 384/±0.40”

20 000/±0.32“

26 000/±0.25“

38 000/±0.17“

44 000/±0.15“TTR ERA 4800

3000/
±2.16“4096/±1.58“5000/±1.30“7000/±0.93“

8192/±0.79“

10 000/±0.65“

13 000/±0.50“––Accuracy of graduation

±5”

±3.7”

±3”

±2.5”

Reference marks

Distance-coded or one

Drum inside diameter*

40 mm

70 mm

80 mm

120 mm

150 mm

180 mm

270 mm

425 mm

512 mmDrum outside diameter*

76.75 mm

104.63 mm

127.64 mm

178.55 mm

208.89 mm

254.93 mm

331.31 mm

484.07 mm

560.46 mm

Mech. permissible speed
With mechanical fault exclusion

10 000 rpm

8500 rpm

6250 rpm

4500 rpm

4250 rpm

3250 rpm

2500 rpm

1800 rpm

1500 rpm

20 000 rpm

15 000 rpm

12 250 rpm

8750 rpm

7500 rpm

6250 rpm

4750 rpm

3250 rpm

2750 rpm

Moment of inertia

0.27 · 10–3
kgm2

0.81 · 10–3
kgm2

1.9 · 10–3
kgm2

7.1 · 10–3
kgm2

12 · 10–3
kgm2

28 · 10–3
kgm2

59 · 10–3
kgm2

195 · 10–3
kgm2

258 · 10–3
kgm2

Maximum angular acceleration withmechanical fault exclusion

20 000 rad/s2 14 000 rad/s2 6600 rad/s2

2700 rad/s2

1800 rad/s21000 rad/s2

1300 rad/s2

900 rad/s2

1200 rad/s2

Permissible axial movement

 ±0.5 mm (scale drum relative to the scanning head)

Protection EN 60529

Complete encoder after mounting: IP00; with sealing-air cover: IP40

Mass

 0.28 kg 2.3 kg

 2.6 kg

 3.8 kg

 3.6 kg

Signal periods/
interpolation error
per signal period1)

Without mechanical fault exclusion

 0.41 kg 0.68 kg 1.2 kg±2”

 1.5 kg* Please select when ordering	The interpolation error within one signal period and the accuracy of the graduation together yield the encoder-specific error;
for additional errors arising from installation and the bearing of the measured shaft, see Measurement accuracy

1)

50

51

ERA 4280 C, ERA 4480 C, ERA 4880 C
Dimensions

Signal periods

12 000

 D2

ISO 7092 – 6/5 – 200HV – 8.8

16 38420 00028 00032 76840 00052 0000.4
–

 D3
10

 W1 /   /  

ISO 4762 – M3x25 – 8.8

RW

±2.5”

±2”

±1.9”

±1.8”

±1.7”

Interpolation error per
1)
signal period±0.36”±0.24”±0.19”±0.14”±0.12”±0.10”±0.07”

Reference marks

Distance-coded or one

Drum inside diameter*

40 mm

70 mm

80 mm

120 mm/
150 mm

150 mm/
185 mm

180 mm/
210 mm

270 mmDrum outside diameter*

76.75 mm

104.63 mm

127.64 mm

178.55 mm

208.89 mm

254.93 mm

331.31 mm

Mech. permissible speed

20 000 rpm

15 000 rpm

12 250 rpm

8750 rpm

7500 rpm

6250 rpm

4750 rpm

–3

–3

–3

–3

Moment of inertia

0.28 · 10
kgm2



0.83 · 10
kgm2–3

2.0 · 10kgm2

–3

7.1 · 10kgm2/
4.5 · 10–3
kgm2

–3

12 · 10kgm2/
6.4 · 10–3
kgm2

28 · 10kgm2/
20 · 10–3
kgm2

0.07/14 A

2x

 0.2 A

59 · 10kgm2

5:1

0.25/50 C 0.30 kg

 1.2 kg/
 0.66 kg

 1.5 kg/
 0.66 kg

 2.3 kg/ 1.5 kg

 2.6 kg

15°

 D1 + 1

α

15°
11.5



0.25/50 A

0.75 ± 0.1

R

Mass

< 50
> 2.9

Complete encoder after mounting: IP00, with sealing-air cover: IP40

Ø 3.7

17.5°



7.2

Protection EN 60529

 0.69 kg>  D2 + 12

7.5

D-D

Permissible axial movement  ±0.5 mm (scale drum relative to the scanning head) 0.42 kg

A

M3

11

Rz 16

4

Rz 16

55°

3.1

±3”

6.5

±4”

0.05 A

X>11
12

Accuracy of graduation19
4  0.1<  D1 - 10

R2

.1
±0

0.5 
–

Steel drum
–6 –1
therm  10.4 · 10 K

ISO 4762 – M5x20 – 8.8
ISO 4762 – M6x25 – 8.8

1 ± 0.2 x 45°

Measuring standard
Coefficient of expansion



0.3 ± 0.05 x 45°

TTR ERA 4202 C with 20 µm graduation period

0.3 ± 0.05 x 45°

Scale drum withthree-point centering

13* Please select when ordering	The interpolation error within one signal period and the accuracy of the graduation together yield the encoder-specific error;
for additional errors arising from installation and the bearing of the measured shaft, see Measurement accuracy

12

1)

G

23 ± 0.5

46
30.5

C

D

M

7.75

C

2.75

D

13

C



E1
W1 = Without mechanical fault exclusion
W2 = With mechanical fault exclusion,  = Mounting possibilities
 = Bearing of mating shaft
W = Mating diameter (shaft)
1 =	Permissible axial motion of the motor shaft: ±0.5 mm
2 = Cable support

52

3 = Positive direction of rotation
4 = Incremental track
5 = Reference pulse track
6 = Space for mounting aid
7 =	With mechanical fault exclusion:a = 11.5 mm ±0.1 mm

 0.2 AC-C



M5: > 7
M6: > 98 = Signal-quality indicator
9 = Mounting aid (accessory)
10 = Roundness of mating diameter (shaft)
11 = Proposed design for undercut
12 =	Back-off thread; not permitted for
drum fastening

53

ERA 4202 C
Dimensions


a





ISO 4762 – M3x20 – 8.8
ISO 4762 – M5x20 – 8.8

 D3

ISO 7092 – 5/3 – 200HV - 8.8

 D2

Rz 16

 W /  D1
 D1

ISO 4762 – M3x25 – 8.8

0.1/20 A

X

0.1 A

A

0.05 A

X

Rz 16



15°

5.3

4
 0.2 AA

M3

6x/12xM

0.3±0.05x45°

>60

A–A

E2

0.07/14 A

4±0.1



1+0.5
0

2x

 D1

6.4

11
12

19
4  0.1

Rz 16

2.5

16.5

0.75±0.1

5:1

0.3±0.05x45°

ISO 4762 – M3x(a+4) – 8.8
ISO 7092 – 3 – 200HV – 8.8

>16

II

 0.2 A7.5

D-D

 D1+0.4
1:1

7.2
11.5

0.25/50 C

Ø 3.7



0.75 ± 0.1

R

< 50
>2.9




 A

11

40



A

3

23 ± 0.5

 3.4

46
30.5

C
1:1

7.75

 0.2 B 2x

D

A

2.75

D
 40 –0.001/–0.005

 40 +0.004

 40 +0.004/+0.000

0.001

 50

 76.75







13


E1

  10

 229.46







54

,  = Mounting possibilities
 = Bearing of mating shaft
W = Mating diameter (shaft)
1 =	Permissible axial motion of the motor shaft: ±0.5 mm
2 = Cable support

3 = Positive direction of rotation
4 = Incremental track
5 = Reference pulse track
6 = Space for mounting aid
7 =	With mechanical fault exclusiona = 11.5 mm ±0.1 mm

8 = Signal-quality indicator
9 = Mounting aid (accessory)
10 =	Marking for drum centering (3x120°)

55

ERA 4480 C
With sealing-air coverII
ISO 4762 – M3x(a+4) – 8.8
ISO 7092 – 3 – 200HV – 8.8


0.1/20 A



A

>16

a

0.05

0.75±0.1

2.5

E2

a ... g = Sealing-air cover version
A = Bearing
1 = Mounting clearance: 0.15 mm (scanning head)
2 = Mounting clearance: 0.15 mm (sealing-air cover)
3 = Cable support
4 = Signal-quality indicator
5 = Sealing-air connecting piece
6 = Reference mark position



< 50

A-A





>60

1+0.5
0



M5: min. 7
M6: min. 9

4±0.1

16.5



1:1



40



A
 3.4

1:1





3


0.2

B 2x

A

 104.63

 127

 117

 105.2

 208.89

 232

 222

 209.4

 278

 268

 354

 344

 331.31

 332

Further information:
For CAD data, visit cad.heidenhain.com

56

57

ECM 2400 series
Absolute angle encoder with magnetic scanning• Consists of a scanning head and scale drum
• Also for safety-related applications• Resistant to contamination
Scanning head

AK ECM 2410

AK ECM 2490 F

AK ECM 2490 M

Interface

EnDat 2.2

Fanuc Serial Interface;Þi Interface

Mitsubishi high speed interface

Ordering designation

EnDat22

Fanuc05

Mit03-4

Clock frequency

 16 MHz–

Calculation time tcal

 5 µs–Functional safety
for applications with up to• SIL 2 as per EN 61508(further basis for testing: IEC 61800-5-3)• Category 3, PL “d” as per
EN ISO 13849-1:2015–

PFH

 25 · 10

Electrical connection

Cable (1 m) with 8-pin M12 coupling (male)–9

1)(up to 6000 m above sea level)

Cable length≤ 30 mSupply voltage

DC 3.6 V to 14 V

Power consumption (max.)

At 3.6 V: 1.1 W
At 14 V: 1.3 W

Current consumption (typical)

At 5 V: < 200 mA (without load)

Vibration 55 Hz to 2000 Hz
Shock 6 ms
With mechanical fault exclusion
Without mechanical fault exclusion≤ 400 m/s2 (EN 60068-2-6)

Operating temperature–10 °C to 80 °C

Protection EN 60529

IP67

Mass 	Scanning headCable
M23 coupling 40 g (without cable) 35 g/m
 15 g–≤ 400 m/s2 (EN 60068-2-27)≤ 1000 m/s2 (EN 60068-2-27)

1)	With HEIDENHAIN cable;
clock frequency  8 MHz

58

59

Scale drum

TTR ECM 2400 with a graduation period  400 µm

Measuring standard
Coefficient of expansion

Steel drum
–6 –1Þtherm  10 · 10 K

Signal periods

900

1024

1200

1400

1696

2048

2600

Drum inside diameter*

70 mm

80 mm/95 mm

105 mm/120 mm

130 mm

160 mm

180 mm

260 mmDrum outside diameter*113.16 mm

128.75 mm

150.88 mm

176.03 mm

213.24 mm

257.50 mm

326.90 mm

Accuracy of graduation

±8”

±7”

±6”/±8”

±5.5”

±4.5”

±4”

±3.5”

Interpolation error per
signal period

±9”

±8”

±7”

±6”

±5”

±4”

±3”

Positions per revolution

8 388 608 (23 bits)

16 777 216 (24 bits)

33 554 432 (25 bits)

Measuring step

0.154”

0.077”

0.039”

Safety-relevant measuring step 0.7° (9 bits)

0.35° (10 bits)

0.18° (11 bits)

Safe position1) 2)

1.76°

0.88°

0.44°

Mech. permissible speed≤ 14 500 rpm≤ 13 000 rpm/
≤ 12 500 rpm≤ 10 500 rpm≤ 9000 rpm≤ 7000 rpm≤ 6000 rpm≤ 4500 rpm

Max. angular acceleration

9000 rad/s2

6000 rad/s2/
9000 rad/s2

4900 rad/s2/
7000 rad/s2

3300 rad/s2

1900 rad/s2

820 rad/s2

560 rad/s2

Electrically permissible
shaft speed≤ 29 000 rpm≤ 25 000 rpm≤ 21 500 rpm≤ 18 500 rpm≤ 15 000 rpm≤ 12 500 rpm≤ 10 000 rpm

Moment of inertia

1.5 · 10–3 kgm2

2.6 · 10–3 kgm2/
2.1 · 10–3 kgm2

4.4 · 10–3 kgm2/
3.4 · 10–3 kgm2

7.4 · 10–3 kgm2

16 · 10–3 kgm2

37 · 10–3 kgm2

76 · 10–3 kgm2

Permissible axial movement≤ ±0.75 mm

Mass

 0.69 kg 0.89 kg/ 0.65 kg 1.0 kg/
 0.72 kg 1.2 kg

 1.8 kg

 3.0 kg 3.5 kg* Please select when ordering
1)
Further deviations may arise in the downstream electronics after position value comparison (contact mfr. of the downstream electronics)2)
Mechanical coupling: for fault exclusion for the loosening of the scanning head and scale drum, see Functional safety

60

61

ECM 2400
Dimensions

Rz 16

A
0.04 A



D1

W1

W2

D2

D3

E

G

 70 +0/–0.008

 70 +0.010/+0.002

 70 +0.019/+0.011

 85

 113.16

62.3

6x M6

 80 +0/–0.008

 80 +0.010/+0.002

 80 +0.022/+0.014

 95

 128.75

70.1

6x M6

 95 +0/–0.010

 95 +0.013/+0.003

 95 +0.029/+0.019

 110

 128.75

70.1

6x M6

 105 +0/–0.010

 105 +0.013/+0.003

 105 +0.031/+0.021

 120

 150.88

81.2

6x M6

 130 +0/–0.012

 130 +0.015/+0.003

 130 +0.041/+0.029

 145

 176.03

93.7

6x M6

ISO 4762−M4−8.8

< 3.8

0.2 A

>    

19.35

22.8

ISO 7092−4−200HV

4.55
8.55

6
40

N

Rz 6.3

5



M5



 

<    

 W1 /  W2

A

00

B

24

42

2:1

5

M4

TTR
EC
M

B

0.15
±0.0
2

B-B

1.5

 50

5.5

B

A-A

5

13.6

21.5

2x

HEID
E
NH
AI

6x60°

6x

50

60°

0.1 B

X
A

Rz 16


TTR ECM 2400
2



 160 +0/–0.012

 160 +0.015/+0.003

 160 +0.049/+0.037

 175

 213.24

112.3

6x M6

 180 +0/–0.012

 180 +0.015/+0.003

 180 +0.055/+0.043

 195

 257.50

134.5

6x M6

 260 +0/–0.016

 260 +0.020/+0.004

 260 +0.082/+0.066

 275

 326.90

169.2

6x M6

W1 = Without mechanical fault exclusion
W2 = With mechanical fault exclusion
 = Bearing of mating shaft
1 = Shaft fit; ensure full-surface contact
2 = Axial tolerance of mating shaft
3 = Cable support
4 = Centering collar
5 = Direction of shaft rotation for ascending position values

62

63

ERM 2200/2400/2900 series
Incremental angle encoder with magnetic scanning• Consists of a scanning head and scale drum
• Multiple graduation periods in accordance with accuracy and speed requirements• Various drum shapes for rotary axes and main spindles• High variety of drum diameters
Scanning head

Graduation period  200 µm
AK ERM 2280

ERM 2200

AK ERM 2283

Graduation period
 1000 µm

AK ERM 2293 M

AK ERM 2480

AK ERM 2420

AK ERM 2410

AK ERM 2980

Interface» 1 VPP

Mitsubishi highspeed Interface(Mit 02-4)2)» 1 VPPTTL x 1, TTL x 2

EnDat 2.22) 3)» 1 VPP

Cutoff frequency (–3dB)
Scanning frequency≥ 300 kHz–––≥ 300 kHz––≥ 350 kHz––≥ 300 kHz–

Integrated interpolation–

16 384 (14 bits)–

16 384 (14 bits)–

Clock frequency–

 8 MHz–Calculation time tcal–

 5 µs–Electrical connection

Cable (1 m) withor without 12-pin
M23 coupling

Cable (1 m) with or without 12-pin
M23 coupling

Cable (1 m) with
8-pin M12
coupling

Cable (1 m) withor without 12-pin
M23 coupling

Cable outlet

Tangential, to the left or rightTangential, to the left or right, axial

Tangential, to theright

Tangential, to theleft or right, axial

Supply voltage

DC 5 V ±0.5 V

DC 3.6 V to 14 V

DC 5 V ±0.5 V

DC 3.6 V to 14 V

DC 5 V ±0.5 V

Current consumption (typical)≤ 150 mA
(without load)≤ 90 mA(without load)≤ 150 mA (without load)

At 5 V: ≤ 90 mA(without load)≤ 150 mA
(without load)

Cable (1 m) with Cable (1 m) with
12-pin M23
8-pin M12
coupling or 12-pin coupling
M12 coupling≤ 35 mA(without load)

Power consumption (max.)

ERM 2900

Graduation period  400 µm

At 3.6 V:
1080 mW
At 14 V:
1300 mW

At 3.6 V: 1080 mW
At 14 V: 1300 mW

Cable length1)≤ 150 m≤ 30 mVibration 55 Hz to 2000 Hz≤ 400 m/s2 (EN 60068-2-6)

Shock 6 ms

≤ 1000 m/s2 (EN 60068-2-27)

Shock: 6 ms,	With fault exclusion for theloosening of the mechanicalconnection≤ 400 m/s2 (EN 60068-2-27)≤ 300 m/s
(EN 60068-2-6)≤ 1000 m/s2
(EN 60068-2-27)≤ 400 m/s2
(EN 60068-2-27)

Operating temperature–10 °C to 60 °C

Protection EN 60529

IP67

Mass		
									Scanning headCable
M23 coupling
M12 coupling≤ 150 m2

≤ 100 m

≤ 400 m/s2 (EN 60068-2-6)≤ 1000 m/s2 (EN 60068-2-27)≤ 400 m/s2 (EN 60068-2-27)≤ 150 m2

≤ 300 m/s
(EN 60068-2-6)≤ 1000 m/s2
(EN 60068-2-27)≤ 400 m/s2
(EN 60068-2-27)≤ 400 m/s2
(EN 60068-2-6)≤ 1000 m/s2
(EN 60068-2-27)≤ 400 m/s2
(EN 60068-2-27)–10 °C to 100 °C

 30 g (without cable) 37 g/m
 50 g 15 g
1)

With HEIDENHAIN cable
Absolute position value after crossing two reference marks
3)
EnDat 2.2 for incremental encoders can be used only after consultation with the controller manufacturer
2)

64

65

Scale drum

TTR ERM 2200
TTR ERM 2203
Grating period  200 µm

Measuring standard
Coefficient of expansion

Steel drum
–6 –1Þtherm  10 · 10 K

Signal periods

1024

1200

1440

1800

2048

2400

2800

3392

4096

5200

7200

Drum inside diameter*

40 mm

40 mm/55 mm

55 mm

70 mm

80 mm/95 mm

105 mm/120 mm

130 mm/140 mm

160 mm

180 mm/220 mm

260 mm/295 mm

380 mm/410 mm

Drum outside diameter*

64.37 mm75.44 mm90.53 mm

113.16 mm

128.75 mm

150.88 mm

176.03 mm

213.24 mm

257.50 mm

326.90 mm

452.64 mm

Accuracy of graduation			
TTR ERM 2200
			TTR ERM 2203

±12”
±8”

±10”
±6.5”

±8.5”
±5.5”

±7”
±4.5”

±6“
±4”

±5.5”/7”±3.5”/5.5”±5”/6”±3.5”/5”

±4”
±2.5”

±3.5”/4.5”±2”/3.5”±3”/4”±1.5 ”/ 3”±2.5 ”/ 3.5”–/–

Interpolation error per
signal period			
TTR ERM 2200
			TTR ERM 2203

±9”
±4.5”

±8”
±4”

±6.5”
±3.5”

±5.5”
±3”

±4.5”
±2.5”

±4”
±2”

±4”
±2”

±3”
±1.5”

±2.5”
±1.5”

±2”
±1”

±1.5”
–/–

Reference markOne or distance-coded

Mech. permissible speed≤ 22 000 rpm≤ 19 000 rpm/
≤ 18 000 rpm≤ 18 500 rpm≤ 14 500 rpm≤ 13 000 rpm/
≤ 12 500 rpm≤ 10 500 rpm≤ 9000 rpm/
≤ 8500 rpm≤ 7000 rpm≤ 6000 rpm≤ 4500 rpm≤ 3000 rpm

Maximum angular acceleration1) 50 000 rad/s2

27 000 rad/s2/
48 000 rad/s2

20 000 rad/s2

9000 rad/s2

6000 rad/s2/
9000 rad/s2

4900 rad/s2/
7000 rad/s2

3300 rad/s2/
4400 rad/s2

1900 rad/s2

820 rad/s2/
1800 rad/s2

560 rad/s2/
1300 rad/s2

570 rad/s2/
960 rad/s2

0.32 · 10–3 kgm2/
0.24 · 10–3 kgm2

0.63 · 10–3 kgm2

1.5 · 10–3 kgm2

2.6 · 10–3 kgm2/
2.1 · 10–3 kgm2

4.4 · 10–3 kgm2/
3.4 · 10–3 kgm2

7.4 · 10–3 kgm2/
6.3 · 10–3 kgm2

16 · 10–3 kgm2

37 · 10–3 kgm2/
23 · 10–3 kgm2

76 · 10–3 kgm2/
42 · 10–3 kgm2

240 · 10–3 kgm2/
150 · 10–3 kgm2

 0.35 kg/ 0.22 kg 0.44 kg 0.69 kg 0.89 kg/ 0.65 kg 1.0 kg/
 0.72 kg 1.2 kg/
 0.99 kg 1.8 kg

 3.0 kg/
 1.6 kg 3.5 kg/
 1.7 kg 5.4 kg/ 3.2 kg

Moment of inertia

0.15 · 10–3 kgm2

Permissible axial movement≤ ±1.25 mm

Mass

 0.21 kg* Please select when orderingWith fault exclusion for the loosening of the mechanical connection

1)

66

67

Scale drum

TTR ERM 2400
Grating period  400 µm

Measuring standard
Coefficient of expansion

Steel drum
–6 –1Þtherm  10 · 10 K

Signal periods

512

600

720

900

1024

1200

1400

1696

2048

Drum inside diameter*

40 mm

40 mm/55 mm

55 mm

70 mm

80 mm/95 mm

105 mm/120 mm

130 mm/140 mm

160 mm

180 mm/220 mm 260 mm/295 mm 380 mm/410 mm 450 mm

512 mmDrum outside diameter*

64.37 mm75.44 mm90.53 mm

113.16 mm

128.75 mm

150.88 mm

176.03 mm

213.24 mm

257.50 mm

326.90 mm

452.64 mm

484.07 mm

603.52 mm

Accuracy of graduation

±13”

±11”

±10”

±8”

±7”

±6”/8”±5.5”/7”±4.5”±4”/5”±3.5”/4”±3”/3.5”

±3.5”

±3”

Interpolation error per
signal period±18”±15.5”±13”±10.5“

±9”

±8”

±6.5”

±5.5”

±4.5”

±3.5”

±3”

±2.5”

±2”

Reference markOne or distance-coded

Mech. permissible speed≤ 22 000 rpm≤ 19 000 rpm/
≤ 18 000 rpm≤ 18 500 rpm≤ 14 500 rpm≤ 13 000 rpm/
≤ 12 500 rpm≤ 10 500 rpm≤ 9000 rpm/
≤ 8500 rpm≤ 7000 rpm≤ 6000 rpm≤ 4500 rpm≤ 3000 rpm≤ 3000 rpm≤ 1600 rpm

Maximum angular acceleration1) 50 000 rad/s2

27 000 rad/s2/
48 000 rad/s2

20 000 rad/s2

9000 rad/s2

6000 rad/s2/
9000 rad/s2

4900 rad/s2/
7000 rad/s2

3300 rad/s2/
4400 rad/s2

1900 rad/s2

820 rad/s2/
1800 rad/s2

560 rad/s2/
1300 rad/s2

570 rad/s2/
960 rad/s2

470 rad/s2

230 rad/s2

2.6 · 10–3 kgm2/ 4.4 · 10–3 kgm2/
2.1 · 10–3 kgm2 3.4 · 10–3 kgm2

7.4 · 10–3 kgm2/
6.3 · 10–3 kgm2

16 · 10–3 kgm2

37 · 10–3 kgm2/
23 · 10–3 kgm2

76 · 10–3 kgm2/
42 · 10–3 kgm2

235 · 10–3 kgm2/
151 · 10–3 kgm2

153 · 10–3 kgm2

713 · 10–3 kgm2

 0.89 kg/ 0.65 kg 1.2 kg/
 0.99 kg 1.8 kg

 3.0 kg/
 1.6 kg 3.5 kg/
 1.7 kg 5.4 kg/ 3.2 kg

 2.8 kg 9.1 kg

Moment of inertia

0.15 · 10–3 kgm2 0.32 · 10–3 kgm2/ 0.63 · 10–3 kgm2 1.5 · 10–3 kgm2
0.24 · 10–3 kgm2

Permissible axial movement≤ ±1.25 mm

Mass

 0.21 kg 0.35 kg/ 0.22 kg 0.44 kg 0.69 kg 1.0 kg/0.72 kg

2600

3600

3850

4800

* Please select when ordering
1)
With fault exclusion for the loosening of the mechanical connection

68

69

Scale drum

TTR ERM 2404
Grating period  400 µm

Scale drum

TTR ERM 2405
Grating period  400 µm

Measuring standard
Coefficient of expansion

Steel drum
–6 –1
therm  10 · 10 K

Measuring standard
Coefficient of expansion

Steel drum
–6 –1
therm  10 · 10 K

Signal periods

360

400

512

1024

Signal periods

512

600

Drum inside diameter*

30 mm

30 mm

40 mm/55 mm 55 mm/60 mm 80 mm

100 mmDrum inside diameter*

40 mm

55 mm

Drum outside diameter*

45.26 mm50.29 mm64.37 mm75.44 mm

113.16 mm

128.75 mm

Drum outside diameter*

64.37 mm75.44 mm

Accuracy of graduation

±24”

±21”

±17”

±14”

±10”

±9”

Accuracy of graduation

±17”

±14”

Interpolation error per
signal period±25.5“±23“±18“±15.5“±10.5“±9“

Interpolation error per
signal period±18“±15.5“

Reference markOne

Reference markOne

Mech. permissible speed≤ 60 000 rpm

Mech. permissible speed≤ 33 000 rpm≤ 27 000 rpm

Moment of inertia

0.11 · 10–3 kgm2

0.16 · 10–3 kgm2

Permissible axial movement≤ ±0.5 mm

Mass

 0.15 kg

Moment of inertia–30.027 · 10
kgm2

≤ 54 000 rpm–30.045 · 10
kgm2

600

≤ 42 000 rpm≤ 38 000 rpm–30.12 · 10
kgm2/
0.06 · 10–3
kgm2

900

≤ 36 000 rpm≤ 30 000 rpm–3≤ 22 000 rpm–30.19 · 10
kgm2/
0.16 · 10–3
kgm2

1.0 · 10≤ 20 000 rpm
2

kgm

–3

1.4 · 102kgm

Permissible axial movement≤ ±0.5 mm

Mass

 0.07 kg

Scale drum

TTR ERM 2904
Grating period  1000 µm

Measuring standard
Coefficient of expansion

Steel drum
–6 –1
therm  10 · 10 K

Signal periods

180

192

256

300

400

Drum inside diameter*

35 mm

40 mm

55 mm

60 mm

100 mmDrum outside diameter*

54.43 mm

58.06 mm77.41 mm90.72 mm

120.96 mm

Accuracy of graduation

±72“

±68”

±51”

±44”

±33”

Interpolation error per
signal period

±72“

±68“

±51“

±44“

±33“

Reference markOne

Mech. permissible speed≤ 50 000 rpm≤ 47 000 rpm≤ 35 000 rpm≤ 29 000 rpm≤ 16 000 rpm

Moment of inertia

0.06 · 10–3 kgm2

0.07 · 10–3 kgm2

0.22 · 10–3 kgm2

0.45 · 10–3 kgm2

0.93 · 10–3 kgm2

Permissible axial movement≤ ±0.5 mm

Mass

 0.11 kg 0.11 kg 0.19 kg 0.30 kg

 0.30 kg 0.14 kg* Please select when ordering
 0.10 kg 0.16 kg/ 0.07 kg 0.17 kg/ 0.13 kg 0.42 kg 0.42 kg* Please select when ordering

70

71

ERM 2200/2203/2400
Dimensions


50



T

2:1

2x

Cable outlet

31.4

 0.2 AISO 4762−M4−8.8

24

1.5

HEIDENHAIN

Tangential, to the right

5.5

TTR
ER
M

M4

d

11

H

ISO 7092−4−200HV

4.5

00

8.5

 W1 /  W2

40
5
5
6

6

N



HEIDENHAIN

15
Rz 16

Tangential, to the left

A

 4.5

HEID
E
NH
AI

K

T

HEIDENHAIN

Axially

TTR ERM 2200
TTR ERM 2203
TTR ERM 2400

W1 = Without mechanical fault exclusion
W2 = With mechanical fault exclusion,  = Mounting possibility for scanning head
 = Bearing of mating shaft
1 = Shaft fit; ensure full-surface contact
2 = Axial tolerance of mating shaft
3 = Reference mark position
4 = Cable support
5 = Centering collar
6 = Direction of shaft rotation for ascending position values

Scanning head

H

T

H
T
AK ERM 2280/2283 17 mm
0.02 mm
AK ERM
2280/2283
17 mm
mm
AK ERM
2293
19.5 mm 0.02
0.02mm
AK ERM
2420/2480
AK ERM
2420/248017 mm
17 mm
AK ERM
2410 2410
AK ERM

0.04
mm
0.04
mm
19.5 19.5mm mm 0.04
mm
0.04
mm

Mounting clearance d(with spacer shim)

K

0.05 mm0.050.05
mm mm

K
13.6 mm
13.6
15.9mmmm

0.150.15
mm mm
0.15
0.15 mm mm

13.6
13.6mmmm
15.9
15.9mm
mm

6.5

D1

W1

W2

D2

D3

E

G

¬ 40 +0/–0.007¬ 40 +0.009/+0.002¬ 40 +0.010/+0.003¬ 50¬ 40 +0/–0.007¬ 40 +0.009/+0.002¬ 40 +0.010/+0.003¬ 50¬ 64.37

37.9

6x M6

¬ 75.44

43.4¬ 55 +0/–0.008¬ 55 +0.010/+0.002¬ 55 +0.015/+0.007

6x M6

¬ 65

¬ 75.44

43.4¬ 55 +0/–0.008¬ 55 +0.010/+0.002

6x M6¬ 55 +0.015/+0.007¬ 70¬ 90.53

51.0

6x M6

¬ 70 +0/–0.008¬ 80 +0/–0.008¬ 70 +0.010/+0.002¬ 70 +0.019/+0.011¬ 85¬ 113.16

62.3

6x M6

¬ 80 +0.010/+0.002¬ 80 +0.022/+0.014¬ 95¬ 128.00

70.1

6x M6

¬ 95 +0/–0.010¬ 105 +0/–0.010¬ 95 +0.013/+0.003¬ 95 +0.029/+0.019¬ 110¬ 128.75

70.1

6x M6

¬ 105 +0.013/+0.003¬ 105 +0.031/+0.021¬ 120¬ 150.88

81.2

6x M6

¬ 120 +0/–0.010¬ 120 +0.013/+0.003¬ 120 +0.036/+0.026¬ 135¬ 150.88

81.2

6x M6

¬ 130 +0/–0.012¬ 120 +0.015/+0.003¬ 130 +0.041/+0.029¬ 145¬ 176.03

93.7

6x M6

¬ 140 +0/–0.012¬ 140 +0.015/+0.003¬ 140 +0.044/+0.032¬ 155¬ 176.03

93.7

6x M6

¬ 160 +0/–0.012¬ 160 +0.015/+0.003¬ 160 +0.049/+0.037¬ 175¬ 213.24

112.3

6x M6

¬ 180 +0/–0.012¬ 180 +0.015/+0.003¬ 180 +0.055/+0.043¬ 195¬ 257.50

134.5

6x M6

¬ 220 +0/–0.014¬ 220 +0.018/+0.004¬ 220 +0.069/+0.055¬ 235¬ 257.50

134.5

6x M6

¬ 260 +0/–0.016¬ 260 +0.020/+0.004¬ 260 +0.082/+0.066¬ 275¬ 326.90

169.2

6x M6

¬ 295 +0/–0.016¬ 295 +0.020/+0.004¬ 295 +0.093/+0.077¬ 310¬ 326.90

169.2

6x M6

¬ 380 +0/–0.018¬ 380 +0.022/+0.005¬ 380 +0.119/+0.101¬ 395¬ 452.64

232.0

12x M6¬ 410 +0/–0.020¬ 410 +0.025/+0.005¬ 410 +0.130/+0.110¬ 425¬ 452.64

232.0

12x M6¬ 450 +0/–0.020¬ 450 +0.025/+0.005¬ 450 +0.142/+0.122¬ 465¬ 484.07

247.7

12x M6¬ 512 +0/–0.022¬ 512 +0.027/+0.005¬ 512 +0.161/+0.139¬ 528¬ 603.52

307.5

12x M6Further information:
For CAD data, visit cad.heidenhain.com

72

73

ERM 2404/2405/2904
Dimensions

AK ERM 2480
B-B



5
ISO 7092

2xM4

1

TT
R

Tangential, to the rightØ 0.2 A

M
04
24

2

HEIDENHAIN

ISO 4762d

ER

Cable outlet

5

6
IN
HA
N

7

HE
ID
E



6
13
Rz 16

TTR ERM 2404
TTR ERM 2904

HEIDENHAIN

0.04 A

Tangential, to the left
 

TT
R

ER

M



04
24

IN
HA
N

HEIDENHAIN

Axially



HE
ID
E

3

TTR ERM 2405
TT
R

ER
05
24

TTR ERM 2404
TTR ERM 2405

IN
HA
N

5

M

4

HE
ID
E

TTR ERM 2904
,  = Mounting possibility for scanning head
 = Bearing
1 = Marking for reference mark, position tolerance relative to reference mark ±5°
2 = Direction of shaft rotation for ascending position values
3 = Centering collar
4 = Clamping area (valid for both sides)
5 = Slot for machine key 4 x 4 x 10 (as per DIN 6885 Form A)

AK ERM 2480

Mounting clearance d(with spacer shim)
0.15 mm

AK ERM 2980

0.30 mmScanning head

D1

W1

D2

E

¬ 30 +0.010/+0.002¬ 30 +0/–0.006¬ 45.26

28.3¬ 30 +0.010/+0.002¬ 30 +0/–0.006¬ 50.2930.9¬ 40 +0.010/+0.002¬ 40 +0/–0.006¬ 64.3737.9¬ 55 +0.010/+0.002¬ 55 +0/–0.006¬ 64.3737.9¬ 55 +0.010/+0.002¬ 55 +0/–0.006¬ 75.44

43.4¬ 60 +0.010/+0.002¬ 60 +0/–0.006¬ 75.4443.4¬ 80 +0.010/+0.002¬ 80 +0/–0.006¬ 113.16

62.3¬ 100 +0.010/+0.002¬ 100 +0/–0.006¬ 128.75

70.0¬ 35 +0.010/+0.002¬ 35 +0/–0.006¬ 54.43

32.9¬ 40 +0.010/+0.002¬ 40 +0/–0.006¬ 58.06

34.7¬ 55 +0.010/+0.002¬ 55 +0/–0.006¬ 77.41

44.4¬ 60 +0.010/+0.002¬ 60 +0/–0.006¬ 90.72

51.1¬ 100 +0.010/+0.002¬ 100 +0/–0.006¬ 120.96

66.2

Further information:
For CAD data, visit cad.heidenhain.com

74

75

ERA 7000 series
Incremental angle encoder for high accuracy• Steel scale tape for internal mounting• Full-circle and segment versions, also for very large diameters• Consisting of a scanning head and scale tape

ERA 7480

Scanning head

AK ERA 7480

Interface» 1 VPP

Cutoff frequency –3 dB

 350 kHzElectrical connection

Cable 1 m with M23 coupling (12-pin)

Cable length 150 m (with HEIDENHAIN cable)

Supply voltage

DC 5 V ±0.5 V

Current consumption< 100 mA (without load)

Vibration 55 to 2000 Hz
Shock 6 ms

 200 m/s2 (EN 60068-2-6)
 1000 m/s2 (EN 60068-2-27)

Operating temperature–10 °C to 80 °C

Mass 20 g (without cable)

Scale tape

MSB ERA 7400 C full circle version
MSB ERA 7401 C segment version

Measuring standard
Grating period
Coefficient of expansion

Steel scale-tape with METALLUR graduation
40 µm
–6 –1
therm  10.5 · 10 K

Signal periods1)

36 00045 00090 000Accuracy of graduation2)

±3.9”

±3.2”

±1.6”

Interpolation error per2)
signal period

±0.4”

±0.3”

±0.1”

573.20 mm

1146.10 mm

 250 rpm

 220 rpm

Accuracy of the scale tape ±3 µm/m of tape length
Distance-coded

Reference marks
Matingdiameter*

Full circle 458.62 mm
Segment  400 mm

ERA 7481

Mech. permissible speed 250 rpm

Permissible axial movement  0.5 mm (scale relative to the scanning head)–6

K–1 to 12 · 10–6 K–1

Permissible expansion
coefficient of shaft

therm 9 · 10

Protection rating
EN 60529

Complete encoder after mounting: IP00

Mass

 30 g/m* Please select when ordering; wider diameters of up to 3 m are available upon request
1)
Validity for full-circle version; for segment solution depending on the mating diameter and the tape length2)	The accuracy of the graduation and the interpolation error within one signal period together yield the encoder-specific error;
for additional errors arising from mounting and the bearing of the measured shaft, see Measurement accuracy

76

77

ERA 7000
Dimensions

ERA 74x1 scale tape (segment)





















,  = Mounting possibilities
A = Bearingk = Required mating dimensions
1 = Mounting clearance (spacer shim) D<1000: 0.15 mm; D>1000: 0.5 mm
2 = Positive direction of rotation for output signals as per the interface description
3 = Scale tape thickness
4 = Reference mark
5 = Distance between the scale-tape slot floor and the fastening thread
6 = Distance between the scale-tape slot floor and the scanning head’s rear mounting surface
7 = Holes required for fine adjustment
8 = Eccentric bushing (moiré setting)
9 = Scale-tape slot floor ¬ D
10 = Notch for scale-tape disassembly (b = 2 mm)

78

k = Required mating dimensions
s = Beginning of measurement
10 = Notch for scale-tape disassembly (b = 2 mm)
11 = Cam disk for tensioning the scale tape
 = Length of the circular arc in the stress-free zone; pay attention to thickness of scale tape
L = Position of the fastening thread
L1 = Range of traverse
L2 = Measuring range in the arc
n = Signal period
D = Slot-floor diameterÞ = Measuring range in degrees (segment angle)þ = 3.14159...

79

ERA 8000 series
High-accuracy incremental angle encoder• Steel scale tape for external mounting• Full-circle and segment versions, including for very large diameters• Optimized scanning performance for very high reliability• Integrated three-color LED signal quality indicator• Consisting of a scanning head and scale tape

ERA 8480 full-circle version

ERA 8481 segment version,scale tape fastened via clamping elements

Scanning head

AK ERA 8480

Interface» 1 VPP, HSP

Cutoff frequency –3 dB

 1 MHz

Electrical connection

Cable (1 m or 3 m);
12-pin M12 coupling or 12-pin M23 coupling

Cable length 150 m (with HEIDENHAIN cable)

Supply voltage

DC 5 V ±0.5 V

Current consumption< 130 mA (without load)

Vibration 55 to 2000 Hz
Shock 6 ms

 200 m/s2 (EN 60068-2-6)
 1000 m/s2 (EN 60068-2-27)

Operating temperature–10 °C to 70 °C

Mass	 Scanning head
Cable
Coupling (M12)
Coupling (M23) 20 g (without cable) 20 g/m
 15 g 50 gScale tape

MSB ERA 8400 C full-circle version
MSB ERA 8401 C segment version with tensioning elements
MSB ERA 8402 C segment version without tensioning elements

Measuring standard
Grating period
Coefficient of expansion

Steel scale-tape with METALLUR graduation
40 µm
–6 –1
therm  10.5 · 10 K

Signal periods1)

36 00045 00090 000Accuracy of graduation2)

±4.7”

±3.9”

±1.9”

Interpolation error per2)
signal period

±0.4”

±0.3”

±0.1”

572.72 mm

1145.73 mm

 50 rpm 45 rpm

Accuracy of the scale tape ±3 µm/m of tape length
Distance-coded

Reference marks
Matingdiameter*

Full circle 458.11 mm
Segment  400 mm

Mech. permissible speed 50 rpm

Permissible axial movement  0.5 mm (scale relative to the scanning head)

ERA 8482 segment version,scale tape without clamping elements–6

K–1 to 12 · 10–6 K–1

Permissible expansion
coefficient of shaft

therm 9 · 10

Protection rating
EN 60529

Complete encoder after mounting: IP00

Mass

 30 g/m* Please select when ordering, additional diameters of up to 3 m are available upon request
Validity for full-circle version; for segment solution depending on the mating diameter and the tape length2)	The accuracy of the graduation and the interpolation error within one signal period together yield the encoder-specific error; foradditional errors arising from mounting and the bearing of the measured shaft, see Measurement accuracy
1)

80

81

ERA 8000
Dimensions

A



B

19

30.5 



0.07/14 A
ISO 4762
M3 x 25 - A2

0.02 AA

4.9 ± 0.1 

A-A
B-B

0.25/50 A

11.27 B

0.3 ± 0.01

13

7.5 

R

5.9



M3 (2x)46
2.75

ERA 84x0 scale tape (full circle)

 0.2 A

> 60 14





11.5

0.25/50 A

13

14



4.9 ± 0.1 

1 +0.0502.5

 3.4 (2x) 

40

ISO 4762-M3x(a+5) - A2

 14 CISO 7092-3-200HV - A2

 3.7

ERA 84x1 scale tape (segment)

C-Ca 0.3 ± 0.01

0.1/20 A

13.2 +0.1
0



B

0.1 A
0.025/100 A

-0,05

+0,2

0.1 A

D>1000;max.0.05 A
D<1000;max.0.02 A
0.01/25 A

Ra 1.682

6
2

1.2 ± 0.3

1.2 ± 0.3

>60 10>16 100.5

1145 ± 0.1)

M4x10 ISO 7984

ERA 84x2 scale tape (segment)
25 ± 0.1
8 ± 0.1

L 
L1
L2

45 ± 0.1

25 ± 0.1
45 ± 0.1

8 ± 0.1


5

5
A

0.6

0.6

Ô, Õ = Mounting possibilities
A = Bearingk = Required mating dimensions
1 = Scale-tape slot floor  D
2 = Bend radius R of the cable – Fixed cable > 8 mm
– Frequent flexing > 40 mm
3 = Positive direction of rotation for output signals as per interface description
4 = Reference mark
5 = Scale-tape thickness
6 = Distance between the scale-tape slot floor and the fastening screw
7 = Distance between scale-tape slot floor and scanning head’s rear mounting surface
8 = Floor of pocket is ferromagnetic for fixing the tensioning cleat
9 = Permissible axial motion (scale tape relative to the scanning head)  ±0.5 mm
10 = Space for mounting aid
11 = Spacer shim
12 = Mounting aid
13 = Signal-quality indicator
14 = Length of the chamfer

0.1 A

0.4 ± 0.05

Ra 3.2(= =C

ERA 84x0:  D - (Dx0,00005)
ERA 84x1/84x2:  D± 0.05

 0.2

(

„L“ ± 0.1)		 = Length of the arc in the stress-free zone, pay attention to the scale-tape thickness
L = Position of the two endpiece recesses or fastening thread
L1 = Range of traverse
L2 = Measuring range in the arc
Mounting aid
2300 - ...
1372104-08
n = Signal period
1200
2300
1372104-07
D = Slot-floor diameter
800 - 1200
1372104-06
Þ = Measuring range in degrees (segment angle)þ = 3.14159...
600 - 800
1372104-05
12
480 - 600
1372104-04
400 - 480
1372104-03
340 - 400
1372104-02
300 - 340
1372104-01

ID number(

45 ± 0.1)

2:1

83

Testing and inspection devices, and diagnostics

HEIDENHAIN encoders provide all of theinformation needed for initial setup,monitoring, and diagnostics. The type of
information available depends on whether
the encoder is incremental or absolute andon which interface is being used.
Incremental encoders have 1 VPP, TTL or
HTL interfaces. TTL and HTL encoders
monitor their signal amplitudes internallyand generate a simple fault detection
signal. With 1 VPP signals, an analysis of
the output signals is possible only withexternal testing devices or through the useof computation resources in thedownstream electronics (analog
diagnostic interface).
Absolute encoders use serial datatransmission. Depending on the interface,
additional 1 VPP incremental signals can be
output. The signals are extensively
monitored within the encoder. The
monitoring results (particularly valuation
numbers) can be transmitted to thedownstream electronics along with theposition values via the serial interface(digital diagnostic interface). The
following information is available:• Error message: position value is notreliable• Warning: an internal functional limit of
the encoder has been reached• Valuation numbers:– Detailed information about theencoder’s function reserve– Identical scaling for all HEIDENHAIN
encoders– Cyclic reading capability
This enables the downstream electronics
to evaluate the current status of theencoder with little effort, even in closedloop mode.
For the analysis of these encoders,
HEIDENHAIN offers the appropriate
PWM inspection devices and PWT testing
devices. Based on how these devices areintegrated, a distinction is made between
two types of diagnostics:• Encoder diagnostics: the encoder isconnected directly to the testing or
inspection device, thereby enabling adetailed analysis of encoder functions.
• Monitoring mode: the PWM inspection
device is inserted within the closed
control loop (via suitable testing adapters
as needed). This enables real-time
diagnosis of the machine or equipment
during operation. The available functions
depend on the interface.

84

Diagnostics with the PWM 21 and ATS software

Initial setup with the PWM 21 and ATS software

Further information:
For detailed descriptions regarding
diagnostics, inspection devices andtesting devices, please refer to theInterfaces of HEIDENHAIN Encoders
brochure.

Mastering nanometer accuracy

DR. JOHANNES HEIDENHAIN GmbH
Dr.-Johannes-Heidenhain-Straße 583301 Traunreut, Germany +49 8669 31-0
 +49 8669 32-5061
info@heidenhain.dewww.heidenhain.com
1371806-22 · 1 · 08/2023 · CD · Printed in Germany

HEIDENHAIN
worldwide