Heidenhain: Incremental Rotary Encoder 385420-08 (ERN420)

Measuring angles with rotary encoders with integral bearing for mounting by stator coupling

Mounting variants

In rotary encoders with integral bearing and stator coupling, the graduated disk of the encoder is connected directly to the shaft to be measured. The scanning unit is guided on the shaft via ball bearings, supported by the stator coupling. During angular acceleration of the shaft, the stator coupling must absorb only that torque resulting from friction in the bearing, thereby minimizing both static and dynamic measuring error. Moreover, the coupling mounted on the stator compensates axial motion of the measured shaft. Other benefits of the stator coupling are:

· Simple mounting

· Short overall length

· High natural frequency of coupling

· Hollow-through shaft possible

Rotary encoders with integral bearing that are conceived for separate shaft coupling are designed with a solid shaft. The recommended coupling to the measured shaft compensates radial and axial tolerances. Angle encoders for separate shaft couplings permit higher shaft speeds.

Rotary encoders without integral bearing operate without friction. The two components - the scanning head and the scale disk, drum, or tape - are adjusted to each other during assembly. The benefits are:

· Large diameter of hollow shaft

· For high shaft speeds

· No additional starting torque

Rotary encoders with integral bearing

HEIDENHAIN ERN, ECN and EQN rotary encoders with integral bearing and mounted stator coupling are characterized by simple mounting and short overall length. Possible applications range from simple measuring tasks to position and speed control on servo drives. The hollow shaft of these encoders is slid directly onto and fastened to the shaft to be measured.

ROD, ROC and ROQ rotary encoders from HEIDENHAIN have their own bearings and are sealed. They are robust and compact. These encoders are coupled by the rotor to the measured shaft through a separate coupling that compensates axial motion and misalignment between the encoder shaft and measured shaft.

ExN 400 Features:

· Compact dimensions

· Industrial standard for dimensions and output signals

· Housing outside diameter: 58 mm

ERN 420 (ID: 385420-08)

Incremental rotary encoder with integral bearing 
for mounting by stator coupling
Line count:              5000
Output signal:           TTL
Max. scanning frequency: 300.00 kHz
Power supply:            5 V (+-10 %)
Coupling version:        Stator coupling for plane
                         surface (hole circle Ø 63
                         mm)
Shaft:                   Blind hollow shaft with 
                         clamping ring, diameter 
                         12 mm, depth 24 mm
Degree of protection:    IP64 (EN60529)
Operating temperature:   -40/+100 °C
Electrical connection:   free cable end
Pin configuration:       D294999
Connecting direction:    Cable outlet for axial 
                         and radial use
Included part:           no enclosed part
Cable length:            1.00 m
Please pay attention to the product documentation!