Battery-free multi-turn feedback
The mechanical encoder retains absolute position without a backup battery and supports a 1599-turn operating range.
SPIM28 28 mm Multi-Turn Absolute Stepper Motor
Multi-Turn Absolute Stepper Motor
Compact 28 mm battery-free multi-turn absolute stepper motor with 1599-turn feedback, 9–36 VDC operation, and Modbus/RS485 or CANopen communication for position-retentive automation axes.
Positioning accuracy
High torsional rigidity and constant torsional backlash over the entire gearbox service life ensure consistently high performance
Compactness
High torque density thanks to high performance and short design
Low maintenance
Highest quality standards for a long service life and extended maintenance intervals
Technical data
Position retained across power cycles
Battery-free multi-turn feedback in a compact 28 mm package
The SPIM28 28 mm multi-turn absolute stepper motor combines a stepper motor, drive electronics and a mechanical multi-turn encoder for compact position-retentive motion axes.
Compact integrated control
Motor, driver, encoder and programmable control share one housing, with a driver section limited to 25 mm.
Flexible machine communication
Modbus/RS485 and CANopen options, programmable I/O and built-in control functions simplify distributed automation design.
Engineering information
Technical data
Three motor lengths cover holding torque from 0.08 to 0.24 N·m while sharing the same 28 mm frame and integrated absolute-feedback architecture.
28 mmFrame size
1599 turnsMulti-turn range
9–36 VDCSupply voltage
0.08–0.24 N·mHolding torque
Motor options
SPIM28 model selection
| Model | Body length (mm) | L1 (mm) | Shaft length (mm) | Shaft diameter (mm) | Phase current (A) | Resistance (Ω) | Inductance (mH) | Holding torque (N·m) | Rotor inertia (g·cm²) | Weight (g) |
|---|---|---|---|---|---|---|---|---|---|---|
| IM28ET008 | 57 | 32 | 24 | 5 | 1.0 | 1.5 | 1.1 | 0.08 | 9 | 115 |
| IM28ET018 | 77 | 52 | 24 | 5 | 1.5 | 2.4 | 2.3 | 0.18 | 18 | 205 |
| IM28ET024 | 88 | 63 | 24 | 5 | 1.8 | 1.8 | 2.1 | 0.24 | 30 | 268 |
Feedback and control
Integrated control functions
| Parameter | Value |
|---|---|
| Multi-turn feedback | 1599 turns |
| Encoder resolution | 4096 lines / 16384 counts |
| Communication | Modbus/RS485, CANopen |
| Digital input compatibility | 5–24 VDC |
| Digital output | Open collector, 30 VDC withstand |
| Input filter frequency | 50 kHz–5 MHz; factory default 300 kHz |
| Stored settings | MCU Flash |
| Control functions | Torque modes, software limits, origin setting |
Environment
Operating conditions
| Parameter | Value |
|---|---|
| Maximum speed | 3000 rpm |
| Operating temperature | 0–50°C |
| Maximum humidity | 90% RH, non-condensing |
| Vibration | 60–300 Hz/mm |
| Storage temperature | −20–75°C |
| Cooling | Natural or forced cooling |
Status indication
LED operating and fault codes
| LED sequence | Status |
|---|---|
| Green steady | Motor running |
| Green flashing | Motor stopped |
| 1 red + 1 green | Driver overcurrent |
| 2 red + 1 green | Motor winding open |
| 3 red + 1 green | Input overvoltage |
| 4 red + 1 green | Input undervoltage |
| 5 red + 1 green | Position deviation |
| 6 red + 1 green | Encoder detection error |
Mechanical and electrical integration
Compact absolute positioning with direct machine interfaces
The integrated architecture reduces separate components while providing deterministic feedback, communication and digital I/O for position-retentive axes.
- 28 mm square flange with three selectable motor lengths
- 9–36 VDC power input and 5–24 VDC compatible digital inputs
- RS485, programmable I/O and open-collector output connections
Application fields
For compact equipment that must retain position
Battery-free absolute feedback is useful where axes must recover their known position after power interruption without relying on a backup supply.
Small test equipment
Positioning fixtures, inspection axes and compact laboratory instruments.
Electronics placement
Compact pick-and-place, feeding and alignment mechanisms.
Medical equipment
Controlled positioning modules in compact diagnostic and treatment systems.
Compact robotics
Distributed axes, end effectors and position-retentive motion modules.
System integration
Verified interfaces for machine design
Select the motor length and communication option to suit torque, installation and control requirements.
Supply voltage9–36 VDC
CommunicationModbus/RS485, CANopen
Digital inputs5–24 VDC compatible
Digital outputOpen collector, 30 VDC withstand
Encoder feedback4096 lines / 16384 counts
Discuss your absolute-positioning axis with our engineers.
Share your torque, speed, voltage, communication and installation requirements for product selection and integration support.
Contact us
Would you like to learn more about our solutions?
We would be happy to advise you—personally, competently, and tailored to your requirements.
Perfection in a new dimension
Further Information
Short delivery times available for selected product configurations.
The TP+ HIGH TORQUE enables maximum torque density and maximum torsional rigidity—ideal for demanding applications with dynamic load changes and high positioning accuracy.
alpha Advanced Line gearboxes with increased durability and food-grade lubrication available.
The TP+ for coordinated pinion-rack systems for medium to high requirements. Typical areas of application in wood, plastic, and composite processing, in machining centers, or in automation.
With cynapse® and smart services, you can unleash the full potential of your drive system: sensor data is processed, visualized, and analyzed intelligently. Find out how the combination of gearboxes with cynapse® and our Smart Services can make your digital production faster, safer, and more efficient.
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