Incremental encoders
Siemens

Incremental encoders detect relative movement and deliver a defined number of electrical pulses per revolution, which represent the measurement of the traveled distance or angle.
Incremental encoders operate on the principle of optoelectronic scanning of dividing discs with the transmitted light principle. The light source is a light emitting diode (LED). The light-dark modulation generated as the encoder shaft rotates is picked up by photoelectronic elements. With an appropriate arrangement of the line pattern on the dividing disk connected to the shaft and the fixed aperture, the photoelectronic elements provide two trace signals A and B at 90° to one another, as well as a reference signal R. The encoder electronics amplify these signals and convert them to different output levels.
Signal level |
Benefits |
Analog signals sin/cos with level 1 Vpp |
The analog signal allows the digitization of the trace signals. In order to obtain a fine resolution, the signals are interpolated in the higher-level controller. |
RS422 differential signals (TTL) |
The resolution can be quadrupled by means of edge evaluation. |
HTL (High Voltage Transistor Logic) |
Built-on encoders with an HTL interface are designed for applications with digital inputs with a 24 V level. The resolution can be quadrupled by means of edge evaluation. |
Article No. |
| 6FX2001-3…. | 6FX2001-2…. | 6FX2001-4…0 |
Product name | Motion Control encoder | Motion Control encoder | Motion Control encoder | |
Product designation |
| Incremental encoder | Incremental encoder | Incremental encoder |
Operating voltage DC | V | 5 ± 10 % | 5 ± 10 % | 10 … 30 |
Limit frequency, typical | kHz | ≥ 180 (- 3 dB) | – | – |
Scanning frequency, maximum | kHz | – | 300 | 300 |
No-load current consumption, maximum | mA | 150 | 150 | 150 |
Resolution, maximum | S/R | 2500 | 5000 | 2500 |
Signal level |
| Sinusoidal 1 Vpp | RS422 (TTL) | V |
Outputs protected against short-circuit to 0 V | Yes | Yes | Yes | |
Switching time (10 … 90 %) | ns | – | ≤ 50 | ≤ 200 |
Phase angle, signal A to B | Degrees | 90 ± 10 | 90 | 90 |
| µs | – | ≥ 0.45 | ≥ 0.45 |
Cable length to downstream electronics, maximum1) | m (ft) | 150 (492) | 100 (328) without fault signal 50 (164) with fault signal | 300 (984) |
Accuracy | arcsec | ± 18 mech. × 3600/PPR count z | ± 18 mech. × 3600/PPR count z | ± 18 mech. × 3600/PPR count z |
LED failure monitoring |
| – | High-resistance driver | High-resistance driver |
Maximum mechanical speed | rpm | 12000 | 12000 | 12000 |
Starting torque at 20 °C (68 °F) | Nm (lbf-ft) | ≤ 0.01 (0.01) | ≤ 0.01 (0.01) | ≤ 0.01 (0.01) |
Shaft loading capacity | ||||
| ||||
| N (lbf) | 40 (8.99) | 40 (8.99) | 40 (8.99) |
| N (lbf) | 60 (13.5) | 60 (13.5) | 60 (13.5) |
| ||||
| N (lbf) | 10 (2.25) | 10 (2.25) | 10 (2.25) |
| N (lbf) | 20 (4.50) | 20 (4.50) | 20 (4.50) |
Shaft diameter | ||||
| mm (in) | 6 (0.24) | 6 (0.24) | 6 (0.24) |
| mm (in) | 10 (0.39) | 10 (0.39) | 10 (0.39) |
Shaft length | ||||
| mm (in) | 10 (0.39) | 10 (0.39) | 10 (0.39) |
| mm (in) | 20 (0.79) | 20 (0.79) | 20 (0.79) |
Angular acceleration, maximum | rad/s2 | 105 | 105 | 105 |
Moment of inertia of rotor | kgm2 (lbf-in-s2) | ≤ 2.9 × 10-6 (2.57 × 10-5) | ≤ 2.9 × 10-6 (2.57 × 10-5) | ≤ 2.9 × 10-6 (2.57 × 10-5) |
Vibration (55 … 2000 Hz) according to EN 60068‑2‑6 | m/s2 (ft/s2) | ≤ 300 (984) | ≤ 300 (984) | ≤ 300 (984) |
Shock according to EN 60068‑2‑27 | ||||
| m/s2 (ft/s2) | ≤ 2000 (6562) | ≤ 2000 (6562) | ≤ 2000 (6562) |
Degree of protection | ||||
|
| IP67 | IP67 | IP67 |
|
| IP64 | IP64 | IP64 |
Ambient temperature, during | ||||
Operation | ||||
| ||||
| °C (°F) | -40 … +100 (-40 … +212) | -40 … +100 (-40 … +212) | -40 … +100 (-40 … +212) |
| °C (°F) | – | -40 … +70 (-40 … +158) | – |
| ||||
| °C (°F) | -10 … +100 (+14 … +212) | -10 … +100 (+14 … +212) | -10 … +100 (+14 … +212) |
| °C (°F) | – | -10 … +70 | – |
Net weight | kg (lb) | 0.3 (0.66) | 0.3 (0.66) | 0.3 (0.66) |
EMC |
| EMC Directive 2014/30/EC and regulations of EMC directives (applicable basic standards) | EMC Directive 2014/30/EC and regulations of EMC directives (applicable basic standards) | EMC Directive 2014/30/EC and regulations of EMC directives (applicable basic standards) |
Certificate of suitability |
| CE, CSA, UL | CE, CSA, UL | CE, CSA, UL |
Siemens Absolute Encoders

Absolute encoders output an absolute angular position between 0° and 360°. They operate on the same scanning principle as incremental encoders, but have a greater number of tracks. For example, if there are 13 tracks, then 213 = 8192 steps are coded in the case of single-turn encoders. The code used is a one-step code (gray code). This prevents any scanning errors from occurring. After switching on the machine, the position value is transferred immediately to the controller, travel to a reference point is not necessary.
All absolute encoders are available in single-turn and multi-turn versions.
Single‑turn encoders
Single-turn encoders divide one rotation (360 degrees mechanical) into a specific number of steps, e.g. 8192. A unique code word is assigned to each position. After 360° the position values are repeated.
Multi‑turn encoders
Multi-turn encoders record the number of revolutions in addition to the absolute position within one revolution. To do this, further code discs which are coupled via gear steps with the encoder shaft are scanned. When evaluating 12 additional tracks, this means that an additional 212 = 4096 revolutions can be coded.
Interface |
Benefits |
DRIVE-CLiQ |
|
SSI |
|
EnDat 2.1 |
|
PROFIBUS DP-V2 |
|
PROFINET IO |
|
Data transfer for absolute encoders with SSI interface
n = data word length (13 bits for single-turn and 25 bits for multi-turn)
T = 1 … 10 µs
t cal = ≤ 5 µs
t 1 = ≤ 0.4 µs (without cable)
t 2 = 17 … 20 µs
Article No. |
| 6FX2001-5.D..-1AA0 | 6FX2001-5.S.. | 6FX2001-5.E.. |
Product name |
| Motion Control encoder | Motion Control encoder | Motion Control encoder |
Product designation |
| Absolute encoder | Absolute encoder | Absolute encoder |
Operating voltage DC | V | 24 | 4.75 … 30 | 3.6 … 14 |
Current consumption, approx. |
| |||
| mA | 37 | 90 | 90 |
| mA | 43 | 120 | 120 |
Interface |
| DRIVE-CLiQ | SSI | EnDat 2.1 |
Clock input |
| – | Differential cable receiver acc. to EIA standard RS485 | Differential cable receiver acc. to EIA standard RS485 |
Data output |
| DRIVE-CLiQ | Differential cable driver acc. to EIA standard RS485 | Differential cable driver acc. to EIA standard RS485 |
Short-circuit strength |
| Yes | Yes | Yes |
Transfer rate | Mbit/s | 100 | – | – |
Transfer rate | kHz | – | 100 … 1000 | 100 … 2000 |
Maximum speed |
| |||
| rpm | 14000 | – | – |
| rpm | – | 5000 | 5000 |
| rpm | 12000 | – | – |
| rpm | – | 12000 | 12000 |
|
| |||
| rpm | 15000 | 15000 | 15000 |
| rpm | 12000 | 12000 | 12000 |
Cable length to downstream electronics, maximum1) | m (ft) | 100 (328) | – | – |
| m (ft) | – | 100 (328) | 150 (492) |
| m (ft) | – | 50 (164) | 50 (164) |
| m (ft) | – | – | 10 (32.8) |
Connection |
| Radial flange outlet M12 | Axial/radial flange outlet M23 | Axial/radial flange outlet M23 |
Resolution |
| |||
| bit | 24 | 13 | 13 |
| bit | 36 | 25 | 25 |
Frame |
| |||
| bit | – | 13 | According to EnDat specification |
| bit | – | 25 | According to EnDat specification |
Incremental track | S/R | 2048, 1 Vpp | – | 512, 1 Vpp |
Code type |
| |||
|
| DRIVE-CLiQ | Gray, fir tree format | Dual |
Parameterization capability |
| |||
|
| – | Set to zero | – |
|
| – | Yes | – |
Accuracy | arcsec | ± 20 | ± 60 | ± 60 |
Starting torque at 20 °C (68 °F) | Nm (lbf‑ft) | ≤ 0.01 (0.01) | ≤ 0.01 (0.01) | ≤ 0.01 (0.01) |
Solid shaft loading capacity |
| |||
|
| |||
| N (lbf) | 40 (8.99) | 40 (8.99) | 40 (8.99) |
| N (lbf) | 60 (13.5) | 60 (13.5) | 60 (13.5) |
| ||||
| N (lbf) | 10 (2.25) | 10 (2.25) | 10 (2.25) |
| N (lbf) | 20 (4.50) | 20 (4.50) | 20 (4.50) |
Shaft diameter |
| |||
| mm (in) | 6 (0.24) | 6 (0.24) | 6 (0.24) |
| mm (in) | 10 (0.39) | 10 (0.39) | 10 (0.39) |
| mm (in) | 10 (0.39) or 12 (0.47) | – | – |
Shaft length | ||||
| mm (in) | 10 (0.39) | 10 (0.39) | 10 (0.39) |
| mm (in) | 20 (0.79) | 20 (0.79) | 20 (0.79) |
Angular acceleration, maximum | rad/s2 | 105 | 105 | 105 |
Moment of inertia of rotor | ||||
| kgm2 (lbf-in-s2) | ≤ 2.9 × 10-6 (2.57 × 10-5) | ≤ 2.9 × 10-6 (2.57 × 10-5) | ≤ 2.9 × 10-6 (2.57 × 10-5) |
| kgm2 (lbf-in-s2) | 4.6 × 10-6 (4.07 × 10-5) | – | – |
Vibration (55 … 2000 Hz) according to EN 60068‑2‑6 | ||||
| m/s2 (ft/s2) | ≤ 300 (984) | ≤ 300 (984) | ≤ 300 (984) |
| m/s2 (ft/s2) | ≤ 150 (492) | – | – |
Shock according to EN 60068‑2‑27 |
| |||
|
| |||
| m/s2 (ft/s2) | ≤ 2000 (6562) | ≤ 2000 (6562) | ≤ 2000 (6562) |
| m/s2 (ft/s2) | ≤ 1000 (3281) | – | – |
Degree of protection |
| |||
|
| IP67 | IP67 | IP67 |
|
| IP64 | IP64 | IP64 |
Ambient temperature, during |
| |||
| °C (°F) | -30 … +100 (-22 … +212) | -40 … +100 (-40 … +212) | -40 … +100 (-40 … +212) |
Net weight |
| |||
| kg (lb) | 0.35 (0.77) | 0.35 (0.77) | 0.35 (0.77) |
| kg (lb) | 0.35 (0.77) | 0.35 (0.77) | 0.35 (0.77) |
EMC |
| EMC Directive 2014/30/EC and regulations of EMC directives (applicable basic standards) | EMC Directive 2014/30/EC and regulations of EMC directives (applicable basic standards) | EMC Directive 2014/30/EC and regulations of EMC directives (applicable basic standards) |
Certificate of suitability |
| CE, CSA, UL | CE, CSA, UL | CE, CSA, UL |