Technical specifications

The SOMANET Circulo series is a combination of servo drive, position feedback sensor (encoder), mechanical integration solution, providing an integrated brake option , specifically designed for collaborative robot (cobot) joints and smart actuators.

Power Specification


Circulo 7

Circulo 9

Maximum peak output power

750 W

1850 W

Maximum continuous output power

250 W

630 W

Nominal supply voltage *

24-48 V DC

Maximum supply voltage *

58 V DC cont.; 60 V DC peak

Minimum supply voltage *

14 V DC

Maximum input current DC

18 A

45 A

Maximum continuous phase current **

8 Arms

20 Arms

Maximum peak phase current ***

24 Arms

60 Arms

Maximum peak phase current (sine amplitude) **** 33.6 A 84 A

Maximum efficiency

> 98 %

* Please consider these definitions for supply voltage

** Maximum continuous values can be reached when the thermal mounting guidelines have been considered.

*** Please refer to the load cycle

**** An explanation for the different values used can be found in our System Integration Guide.

General Specification

  Circulo 7 Circulo 9
Supported Communication Standard EtherCAT with Safety over EtherCAT
(EtherCAT and Safety over EtherCAT are registered trademarks and patented technologies licensed by Beckhoff Automation GmbH, Germany)
Number of Phases 3
Supported motors BLDC, PMSM
Integrated safety functions
  • Safe Torque Off (STO)

  • Safe Brake Control (SBC, part of STO function)

  • Safe Stop 1 (SS1) with time monitoring

  • Safe Stop 1 (SS1) with ramp monitoring

    Safe Stop 2 (SS2) with ramp monitoring

  • Safe operating stop (SOS)

  • Safely Limited Speed (SLS)

  • Safe maximum speed (SMS)

  • Safe position

    Safe velocity

Integrated Encoder 1 (multi-turn with battery) (optional) 19 bit, absolute (optional) 20 bit, absolute
Integrated Encoder 2 (optional) 19 bit, absolute (optional) 20 bit, absolute
Incremental Encoder max frequency (external encoder) 1.4 MHz (supports up to 14,000 rpm with a 4,096 resolution incremental encoder)
Hardware protections Overcurrent, Overvoltage, Undervoltage, Overtemperature[1], PWM deadtime, PWM shoot through
Dimensions (see also dimension drawings)

Inner diameter: 20 mm

Outer diameter: 72.2 mm

Height: 21.3 mm

Inner diameter: 40 mm

Outer diameter: 92.2 mm

Height: 22.3 mm

Weight (without encoder rings) 102 g 147 g
Operating temperature

0 - 60°C ambient air (inside the enclosure)

0 - 70°C on the mounting surface (typically B-side / bearing flange of the motor)

Max. installation altitude 2000 m
Storage temperature -35 to 85° C
Humidity Max 90 % rH
Sensors on-board 3 x Iphase , UDC, tmosfet, tcore
Encoder port 1 1 x BiSS-C / SSI
Encoder port 2 1 x ABI / Fast ABI [2] / BiSS-C / SSI / A-Format / HALL
Brake power output 1 A @ 48 V
Brake peak current 4 A
Digital I/O

5x Digital IO (3.3/5 V)

1x Digital Output (3.3/5 V)

1x Digital Input (24 V)

(Safe) Digital I/O

1x Safe Digital Output (3.3/5 V)

2x Safe Digital Input (24 V)

3x Digital IO (3.3/5 V)

1x Digital Output (3.3/5 V)

1x Digital Input (24 V)

Analog In

1x Analog In Single Ended (0-5 V)

1x Analog In Differential (±5 V)

Safe Analog In 1x Safe Analog In Differential (±5 V)
Motor temperature sensor input (user configurable) 1 x KTY (for example KTY84-130) / PT1000 / PT100 [3]
Heatsink Aluminum
Integrated brake Yes (optional)
Compliance with standards

IEC 61800-5-2:2016

CISPR 11 Class B (EN 55011:2016)

IEC 61000-4-6:2013

IEC 61000-4-3:2020

IEC 61000-4-2:2008

IEC 61000-4-8:2009

IEC 61800-5-1:2022

IEC 60204-1:2016

IEC 61158-6-12: 2019

IEC 61800-7:2015


Compliance with European directives CE (EMC Directive 2014/30/EU, Machinery Directive 2006/42/EC)

[1] The Hardware is protected against overtemperature above 114 °C. Since the software has its own temperature protection object which is set to 100 °C by default, this hardware protection will not be triggered.

[2] Fast ABI is supported from firmware 5.0 on

[3] Using a PT100 is not recommended. Click here for details about temperature sensors

Optional Integrated Brake

Brake specifications


Solenoid actuator

Detailed specifications