Absolute Rotary Pulse Encoder GEL 235

General Absolute Encoder Information
The absolute rotary pulse encoder series GEL 235 delivers for each angular position a unique position value via a digital interface with a resolution up to 28 bit. The absolute encoder series includes Singleturn (ST) with up to 16 bit and Multiturn (MT) with 12 bit resolution via a mechanical gear.Features
- Multiturn with mechanical gear
- High resolution 28 bit
- High accuracy ± 0,1°
- SSI up to 2 MHz
- SSI-P (SSI-progammable) by use of Parameter-Kit
- CANopen DS 406, PROFIBUS
- DP
- Sin/Cos differential signal with1 VPP
- Axial / radial connector or cable exit
- Dew-point-proof Protection class up to IP 67
Unique Nonius-evalution
- Measuring principle: magnetic, high resolution
- Evaluation: Nonius-principle
- Measuring scale: metallic code dis
Compact Design for this Absolute Encoder Series
With a standard flange size of 58 mm the housing length for ST and MT with mechanical gear is less than 50 mm.Robust Construction
- Resilient anodised aluminium housing, double-bearings
- The 12 mm steel encoder shaft and the steel code disc form a single robust unit
- The temperature coefficient of all rotating parts is uniform
- Withstands high shock and vibration levels and high acceleration rates
Nonius-Algorithm (Vernier-Algorithm)
The measurement principle of the GEL 235 is based on the magnetic scanning of a code disc made of ferro-magnetic steel, the so called nonius-disc. Magneto-Resistive sensors scan three tracks and deliver three corresponding sinusoidal signals. The phase relation of those three sinusoidal signals is unique with one revolution. Based of the Nonius-principle this phase relation is evaluated and delivers with high resolution and accuracy the absolute position.Interface
The absolute encoder supplies the position values in a binary or gray code by use of a fast SSI-interface. In addition high interpolateable Sin/Cos differential signals with 1 Vpp are delivered. The programming of code, resolution, counting direction and Preset values is optionally possible. With 28 bit resolution and a high data rate up to 2 MHz for SSI mode even highly dynamic motion processes are well controlable. A connectable bus-cap enables the profiles CANopen DS 406 and PROFIBUS DP ENCODER PROFIL V1.1. Integrated rotary selectors for the encoder ID and data rate, a switchable on terminal resistor and diagnostic LEDs supports a fast startup.Magnetic measuring principle
The magneto-resistive scanning of a ferro-magnetic steel- disc offers significant advantages:- suitable for all standard application and furthermore for Real-Heavy-Duty use
- withstands high shock / vibration level
- not influenced by dirt or oil mist
- long term stable temperature characteristics
- full functionality in the presence of condensation:dewpoint-proof
- no aging of the magnetic sensor elements
- withstand aggressive media

With additional bus caps all mechanical variants of the GEL 235 can be used for the fieldbus profiles
CANopen and PROFIBUS DP
Technical Data
General | |
Incremental deviation | < 0.01° |
Repeatability | < 0.01° |
Accurary | ± 0.1° (> 11 Bit) |
Electrical data | |
Operating voltage | 10 to 30 V DC with reverse voltage protection (option: 5 V - 5%, +25%) |
Power consumption | < 1.6 W, without load |
Resolution Singleturn (ST) | 8, 9, 10 to 16 Bit (measuring steps over 360°) |
Resolution Multiturn (MT) | 4, 8, 12 Bit (revolution, mechanical gear) |
Interface | SSI, PROFIBUS Encoder Profile V 1.1, CANopen Encoder Profile DS406 |
Sin/Cos analogue signal | Sin/Cos difference signal 1 VPP, 64 periods per resolution |
Mechanical data | |
Housing diameter, housing length |
58 mm, 46.5 mm |
Clamping flange | Distance contact point : 5 mm Shaft load (radial/axial) at 1,000 min-1 = 160 N / 80 N, at 6,000 min-1 = 100 N / 80 N |
Synchro flange | Distance contact point: 10 mm Shaft load (radial/axial)at 1,000 min-1 = 70 N / 50 N, at 6,000 min-1 = 50 N / 40 N |
Semi hollow shaft | Distance contact point: 1 mm Shaft load (radial/axial) at 1,000 min-1 = 100 N / 20 N, at 6,000 min-1 = 40 N / 20 N |
Material | anodised aluminium |
Weight Singleturn | 300 g |
Weight Multiturn | 310 g |
Operating speed (limit value) Singleturn | 12,000 min-1 |
Operating speed (limit value) Multiturn | 10,000 min-1, 12,000 min-1(short time) |
Shaft sealing ring (optional) |
Protection class: IP 67, Material: Viton, reduced operating speed (max. 6,000 min-1) |
Cable (optional) | halogen-free PUR (6 x 2 AWG, shielded) |
Operating speed |
< 3 Ncm |
Ambient data | |
Protection class | IP 64, IP 67 (optional) |
Shock protection (IEC 68, 2-27) | 2000 m/s², 11 ms |
Vibration protection (IEC 68, 2-6) | 200 m/s², 10 to 2,000 Hz |
Working temperature range | -40 °C to 100 °C |
Operating temperature range | -40 °C to 105 °C (120 °C short time) |
Storage temperature range | -40 °C to 85 °C |
Relative humidity of air max. | 100 % |
Condensation | permissible |
EMC | EN 61000-6-1 to -4 |
Insulation strength | Ri > 1 M? at 500 V AC |
Pin layout SSI, Sin/Cos


At any given rotary position the output signals can be set to preset values. As default the singleturn is to set 2n-1and the multiturn is set to half of its maximum value. The preset can be set electrically by applying Vs to the Preset line for t > 100 ms (do not apply permanently). Alternatively, a preset pushbutton is optionally available, recessed in the encoder base (IP 67). This is to be pushed with a blunt pin for t > 100 ms. By using the optional parameter kit, the preset values can be freely defined.
Counting directionWith view on the encoder shaft the position value increases by rotating the shaft clockwise (CW) (default setting). By applying VS permanently to the CW/CCW line the position value will increase when rotating the shaft counter-clockwise. CCW = increasing position values while turning the encoder shaft clockwise CW = increasing position values while
SSI/SSI=PUsing SSI protocol the allowed data rates are reduced as the cable length increases. It is recommended that the wires of ± Clock and ± Data are each in twisted pair configuration each while the cable is shielded.
Cable lengthUsing SSI protocol the allowed data rates are reduced as the cable length increases. It is recommended that the wires of ± Clock and ± Data are each in twisted pair configuration each while the cable is shielded.
Temperature Range
The storage temperature of -40°C up to 85°C is restricted by the packaging material. A working temperature range from -40°C up to 100°C is permissible, in which a mounted encoder is not allowed to exceed this temperature range. Within the allowed working temperature range the functionality of the absolute rotary encoder is assured (DIN 32878), specifically when the temperature is measured at the encoder housing.
The encoder temperature is affected by the installation conditions (thermal conduction, thermal radiation), the selfheating (bearing friction, electrical power dissipation) and the environmental temperature.
Depending on the operating conditions of the encoder, the working temperature of the encoder can be higher than the environmental temperature.
Depending on the power supply from 5 V DC to 30 V DC a self-heating of up to 10°C can occur. At high rotation speeds > 5000 min-1a self-heating caused by bearing friction of up to 20°C is possible. If the encoder is operated close to its maximum permissible specifications several parameters can affect encoder self-heating. In this case the environmental temperature has to be reduced by suitable methods
Technical data SSI | |
Output code | Binary, gray |
Transmission | Max. 1,200 m depending on transmission rate |
The immunity to interference | High immunity to interference via symmetrical transmission |
Direction of rotation | Adjustable, standard clockwise (CW) with view on the encoder shaft, increasing position values |
Preset | About input level, software optional with pushbutton |
SSI-P (SSI-programmable) | Option: software and hardware (parameter kit) |
Technical data PROFIBUS DP | |
Interface | PROFIBUS DP, Encoder Profile V 1.1 |
Supply voltage | 10 to 30 V DC |
Cable diameter | 8 mm |
Connection | Via bus cap as T-Connector, alternatively cable gland or M12 plug, diagnostics LED, I/O DC-isolated (inductive coupling) |
Programmable function | Resolution, Preset, offset, counting direction, speed output, acceleration output, output of work areas relative to determined values, scalable step number (decimal/binary), multiplier for measuring of lengths auto-recover-to-bus; |
Output code | Binary |
Data rate | 9,6 kBit/s up to 12 Mbit/s adjustable via bus master |
Sensor-ID | 1 to 125 adjustable via rotary selector |
Terminal resistor | Switchable via bus cap (both DIP-Switchers at ON) |
Operating temperature | -40 °C to 85 °C (for short time 100°C) |