Multi-axis servo drive
STOBER SI6 drive controller
Slim 45 mm multi-axis servo drive controllers on a central PS6 supply module, with 5–50 A nominal and up to 105 A maximum current (4 kHz), and the same fieldbus and safety options as SC6.
Key specifications
| Fieldbus | EtherCAT, PROFINET, EtherNet/IP |
|---|---|
| Axes | multi-axis (single and double axis modules) with PS6 supply |
| Continuous current (max) | 50 A |
| Peak current (max) | 105 A |
| Safe torque off | STO via terminals, or STO and SS1 via FSoE/PROFIsafe; SIL 3, PL e (Cat. 4) |
| Width | 45 |
Summarised in our own words from STÖBER Antriebstechnik GmbH + Co. KG's published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Specify Motion is not affiliated with STÖBER Antriebstechnik GmbH + Co. KG. STOBER and SI6 drive controller are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
Alternatives that meet or exceed these figures
Engineers often come to us with a STOBER part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These 3 series from our supply network are the closest match on published figures.
Single-axis 24-70 VDC servo drives from 5 to 60 Arms (180 A peak), in RS (Modbus/pulse/analogue) and CAN (CANopen/analogue) versions. They drive brushless, brushed and PMSM motors including ELVM, with STO SIL3 and backup logic supply on the 40/60 A models.
| Published maximum | SI6 drive controller | ELD2 Series Low-Voltage DC Servo Drives |
|---|---|---|
| Continuous current | 50 A | 60 A meets or exceeds |
| Peak current | 105 A | 180 A meets or exceeds |
| Power | — | 2,500 W |
| Axes | — | 1 |
ADVANCED Motion Controls' ultra-compact, high power-density digital servo drives for 10-90 VDC systems, up to 100 A continuous and 200 A peak. They come in PCB, machine-embedded, panel and development-board formats, carry STO as standard, and run EtherCAT, CANopen or Ethernet/IP. Extended-environment models are rated -40 to +95 C.
| Published maximum | SI6 drive controller | FlexPro Digital Servo Drives (FE, FX, … |
|---|---|---|
| Continuous current | 50 A | 100 A meets or exceeds |
| Peak current | 105 A | 200 A meets or exceeds |
Network-capable AMC digital drives spanning 10-747 VDC and 120-480 VAC, up to 150 A continuous and 250 A peak (27.4 kW peak power), in PCB, panel, machine and vehicle formats. They support almost any motor type and feedback, plus CANopen, EtherCAT, POWERLINK and Modbus.
| Published maximum | SI6 drive controller | DigiFlex Performance Servo Drives (DP,… |
|---|---|---|
| Continuous current | 50 A | 150 A meets or exceeds |
| Peak current | 105 A | 250 A meets or exceeds |
| Power | — | 27,400 W |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
What a multi-axis servo drive is
A multi-axis servo drive controls two or more servo motors from one unit, usually sharing a power supply, DC bus and communication interface. Formats include compact two- to four-axis drives in one housing and modular systems with a common supply module and separate axis modules. Sharing the bus lets energy from a decelerating axis be used by others, reducing braking losses. Most connect to a motion controller or PLC over EtherCAT or another industrial Ethernet network.
When engineers choose a multi-axis servo drive
Choose a multi-axis drive for machines with several coordinated servo axes in one cabinet, such as robots, packaging machines and gantries. It saves space, wiring and cost per axis compared with single drives. The trade-offs are flexibility and fault isolation: axes share the supply, so a supply fault affects all axes, and replacing one module may need specific spare strategy. Mixing very different power levels can be limited by module ranges.
How to specify the STOBER SI6 drive controller
Send these with your enquiry and an engineer can confirm the right SI6 drive controller variant or an equivalent:
- Number of axes and power per axis (A, kW)
- Supply voltage (V AC or DC)
- Network interface and cycle time
- Motor and feedback types
- Shared bus and regenerative energy handling
- Safety functions per axis
- Cabinet size and cooling
Common mistakes to avoid
- Sizing supply module for the sum of peaks without considering simultaneous demand
- Ignoring how one fault affects all axes
- Choosing modules without room for future axes
- Overlooking network cycle time with many axes
STOBER SI6 drive controller: frequently asked questions
What is the STOBER SI6 drive controller?
Slim 45 mm multi-axis servo drive controllers on a central PS6 supply module, with 5–50 A nominal and up to 105 A maximum current (4 kHz), and the same fieldbus and safety options as SC6. Published series figures include continuous current 50 A, peak current 105 A. It is made by STÖBER Antriebstechnik GmbH + Co. KG; Specify Motion can help source it or propose an equivalent.
Who makes the STOBER SI6 drive controller?
The STOBER SI6 drive controller is made by STOBER (STÖBER Antriebstechnik GmbH + Co. KG) and is listed here for engineers comparing options. Specify Motion is not affiliated with STÖBER Antriebstechnik GmbH + Co. KG; brand names are used only to identify the product.
What is the continuous current of the STOBER SI6 drive controller?
The published series maximum continuous current is 50 A. Individual models and sizes in the SI6 drive controller range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the STOBER SI6 drive controller?
Yes. On published figures, Leadshine ELD2 Series Low-Voltage DC Servo Drives and ADVANCED Motion Controls FlexPro Digital Servo Drives (FE, FX, FM, FD, FMP; Micro and Mini sizes) are the closest match from our supply network. An engineer confirms the fit against your application before recommending anything.
What are the benefits of a shared DC bus?
On a shared DC bus, energy regenerated by a decelerating axis can be used by other axes that are accelerating, reducing the energy dissipated in braking resistors. It also reduces wiring and supply components. Sizing must consider simultaneous peak demand on the shared supply.
Are multi-axis drives cheaper than single-axis drives?
Typically, per axis, multi-axis drives cost less and take less cabinet space, because the supply, communication and housing are shared. The saving grows with the number of axes. For machines with only one or two axes, or widely separated axes, single drives can be simpler.
Further reading: How to select a multi axis servo drive · How to select a servo drive · Servo drives
Other multi-axis servo drive series
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