Product Information

ECN 425
EQN 437
Absolute Rotary Encoders
with Hollow Shaft andExpanding Ring Coupling for
Safety-Related Applications

04/2019

ECN 425, EQN 437
Rotary encoders for absolute position values with safe singleturn
information• Installation diameter 65 mm• Expanding ring coupling 07B• Blind hollow shaft Ø 12.7 mm for axial clamping (67M)• IP64 protection

Required mating dimensions

A = Bearing of mating shaft
M1 = Measuring point for operating temperature
M2 = Measuring point for vibration, see D 741714
1 = Clamping screw for coupling ring, width A/F 2, tightening torque 1.25–0.2 Nm
2 = Screw plug, widths A/F 3 and 4, tightening torque 5+0.5 Nm
3 = Screw DIN 6912 – M5x25 – 08.8 – MKL width A/F 4, tightening torque 5+0.5 Nm
4 = Compensation of mounting tolerances and thermal expansion, no dynamic motion permitted
5 = Chamfer at start of thread is obligatory for materially bonding anti-rotation lock
6 = Direction of shaft rotation for ascending position values

Specifications

ECN 425 – Singleturn

EQN 437 – Multiturn

Valid forID 678920-01

ID 678922-01

Functional safety
for applications up toAs single-encoder system for monitoring functions• SIL 1 as per EN 61508 (further basis for testing: EN 61800-5-2)• Category 2, PL c as per EN ISO 13849-1:2015
As single-encoder system for closed-loop functions• SIL 2 as per EN 61508 (further basis for testing: EN 61800-5-2)• Category 3, PL d as per EN ISO 13849-1:2015
Safe in the singleturn range

PFH≤ 10 · 10 –9 (probability of dangerous failure per hour)

Safe position 1)

Encoder: ±1.76° (safety-related measuring step: SM = 0.7°)
Mechanical coupling: ±2° (fault exclusion for loosening of shaft and stator coupling, designed foraccelerations ≤ 300 m/s 2Interface

EnDat 2.2

Ordering designation

EnDat22

Position values per revolution

33 554 432 (25 bits)

Revolutions-Calculation time tcal
Clock frequency≤ 7 µs≤ 8 MHz

System accuracy± 20"

Electrical connection

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

Cable length≤ 100 m (see EnDat description in the Interfaces of HEIDENHAIN Encoders brochure)Supply voltage

DC 3.6 V to 14 V

Power consumption 2) (max.)

At 3.6 V: ≤ 600 mW
At 14 V: ≤ 700 mW

At 3.6 V: ≤ 700 mW
At 14 V: ≤ 800 mW

Current consumption (typical)

At 5 V: 85 mA (without load)

At 5 V: 105 mA (without load)

Shaft

Blind hollow shaft for axial clamping Ø 12.7 mm (67M)

Speed≤ 12 000 rpm

Starting torque at 20 °C (typical)

0.01 Nm

Moment of inertia of rotor

3.6 · 10 –6 kgm 2

Angular acceleration of rotor≤ 5 · 10 4 rad/s 2

Natural frequency of stator coupling≥ 1800 Hz

Axial motion of measured shaft≤ ±0.5 mm

Vibration 55 Hz to 2000 Hz
Shock 6 ms

≤ 300 m/s 2 (EN 60 068-2-6); 10 Hz to 55 Hz constant over distance 4.9 mm peak to peak
≤ 2000 m/s 2 (EN 60 068-2-27)

Min. operating temp.

Stationary cable: –30 °C; Moving cable: –10 °C

Max. operating temp.

100 °C

Trigger threshold of error message
for excessive temperature

125 °C (measuring accuracy of internal temperature sensor: ±4 K)

Relative humidity≤ 93 % (40 °C/21 d as per EN 60 068-2-78); without condensation

Protection EN 60 529

IP64 (see Insulation under General mechanical information in the Encoders for Servo Drives brochure;contamination from the ingress of liquid must be prevented)

Mass≈ 0.25 kg1)
2)

4096 (12 bits)

Further tolerances may apply in subsequent electronics after position value comparison (contact mfr. of subsequent electronics)
See General electrical information in the Interfaces of HEIDENHAIN Encoders brochureMounting

The shaft of the rotary encoder is slid onto the motor’s drive shaft and fastened with a central
screw. It must particularly be ensured that the positive-locking element of the stator coupling
securely engages the corresponding slot in the measured shaft. A screw with material
bonding anti-rotation lock must be used (see Mounting accessories). The stator coupling isclamped by means of an axially tightenable screw in a location hole.
Requirements on the motor side for safe mechanical coupling:
Mating shaft

Mating stator

Material

SteelAluminum

Tensile strength Rm≥ 600 N/mm 2≥ 220 N/mm 2Interface pressure PG≥ 500 N/mm 2≥ 200 N/mm 2

Surface roughness Rz≤ 16 µm

Coefficient of thermal expansion αtherm 10 · 10 –6 K –1 to17 · 10 –6 K –1

≤ 25 · 10 –6 K –1

For the design of the mechanical fault exclusion for the shaft connection, the following
maximum torque Mmax must be considered:
Mmax = 1.0 Nm
The customer’s mechanical design must ensure that the maximum torque Mmax occurring in
the application can be transmitted.

Mounting accessories
ScrewsScrews (central screw, fastening screws) are not included in delivery and can be orderedseparately.
ECN 1325, EQN 1337

Screws 1)

Central screw for
fastening the shaft

DIN 6912-M5×25-08.8-MKL1)

Quantity
ID 202264-55

10 or 100

With coating for material-bonding anti-rotation lockFor further mounting information and mounting aids, please refer to the relevant
mounting instructions and the Encoders for Servo Drives brochure. The mounting canbe tested with the PWM 21 and the ATS software.

Integrated temperature evaluation

This rotary encoder features a temperature sensor integrated in the encoder electronics. The
digitized temperature value is transmitted purely serially over the EnDat protocol. Note thattemperature measurement and transmission are not secure in the sense of functional safety.
With regard to the internal temperature sensor, the encoder supports two-stage cascaded
signaling of excessive temperature. This consists of an EnDat warning and an EnDat error
message.
In compliance with the EnDat specification, when the temperature reaches the warning
threshold for excessive temperature of the internal temperature sensor, it triggers an EnDatwarning (EnDat memory area for operating status, word 1 – warning, bit 2 1 – temperature
exceeded). This warning threshold for the internal temperature sensor is saved in the EnDat
memory area “Operating parameters,” word 6 – “Threshold sensitivity warning bit forexceeded temperature,” and can be individually adjusted. A product-specific default value
is saved before shipping. The temperature measured by the internal temperature sensor
is higher by a device-specific and application-specific amount than the temperature at themeasuring point M1 in accordance with the dimension drawing.
The encoder features a further, but non-adjustable trigger threshold for the EnDat error
message for excessive temperature of the internal temperature sensor, which when
exceeded triggers an EnDat error message (EnDat memory area for operating status, word
0 – error messages, bit 2 2 – position and, in the additional datum 2 operating status error
sources, bit 2 6 – temperature exceeded). This threshold sensitivity depends on the device
and is shown in the specifications.
HEIDENHAIN recommends setting the warning threshold depending on the application
so that it lies sufficiently below the trigger threshold for the EnDat error message forexcessive temperature. The encoder’s intended use requires compliance with the operating
temperature at the measuring point M1.

Electrical connection

Cables with M12 connecting elements
PUR connecting and adapter cables Ø 6 mm; (4 × 0.14 mm²) + (4 × 0.34 mm 2 ); AP = 2 × 0.34 mm 2
Connecting cable with 8-pin M12 connector(female) and 8-pin M12 coupling (male)

ID 368330-xx

Connecting cable with 8-pin M12 connector(female) and free cable end

ID 634265-xx 1)

Adapter cable with 8-pin M12 connector (female)and 15-pin D-sub connector (female)

ID 533627-xx

Adapter cable with 8-pin M12 connector (female)and 15-pin D-sub connector (male)

ID 524599-xx

AP:1)

Cross section of power supply lines
Connecting element must be suitable for the maximum clock frequency used

The electromagnetic compatibility of the complete system must be ensured!
Note for safety-related applications: Provide bit error rate as per specification 533095!

Pin layout
8-pin M12 couplingPower supply

Absolute position values

82

51

3

4

76UP

Sensor UP0V

Sensor 0 VDATA

DATA

CLOCK

CLOCK

Brown/GreenBlueWhite/GreenWhite

Gray

Pink

VioletYellow

Cable shield connected to housing; Up = Power supply
Sensor: The sense line is connected in the encoder with the corresponding power supply.
Vacant pins and wires must not be used.
Note for safety-related applications: Only completely assembled HEIDENHAIN cables are qualified. Do not modify cables or exchange
their connectors without first consulting with HEIDENHAIN Traunreut.

598340 · 03 · A · 02 · 04/2019 · PDF

This Product Information document supersedes all previous editions, which thereby
become invalid. The basis for ordering from HEIDENHAIN is always the Product
Information document edition valid when the order is made.
Further information: Adhere to the information in the following documents toensure the correct and intended operation of the encoder:• Encoders for Servo Drives brochure: 208922-xx• Interfaces of HEIDENHAIN Encoders brochure: 1078628-xx• ECN 425, EQN 437 Mounting Instructions: 722594-xx• Safety-Related Position Measuring Systems Technical Information: 596632-xx• For implementation in a safe control or inverter: Specification 533095• Cables and Connectors brochure: 1206103-xx