Encoder Specifications

SOMANET Circulo is available in different versions:

• With one additional encoder ring in two positions which is

  mounted on the motor for position control, velocity control and commutation.

• With two additional encoder rings, one mounted on the motor for velocity control (dual loop control) and commutation and one mounted on the joint for position control.

Circulo 7

	Position 1 (inner)	Position 2 (outer)
Operating principle	Off-axis magnetic field scanning
Scanning principle	2 arrays of Hall sensors for 2 magnetic tracks
Interface	BiSS
Encoder resolution	19 bit
Absolute position	On both encoders
Multiturn resolution	18 bit (battery based)
Maximum speed	12000 rpm

Circulo 9

	Position 1 (inner)	Position 2 (outer)
Operating principle	Off-axis magnetic field scanning
Scanning principle	2 arrays of Hall sensors for 2 magnetic tracks
Interface	BiSS
Encoder resolution	20 bit
Absolute position	On both encoders
Multiturn resolution	18 bit (battery based)
Maximum speed	6000 rpm

Accuracy and repeatability of the integrated encoders

Circulo 7

	Position 1 (inner)	Position 2 (outer)
Accuracy	±90” * ±0.025°	±72” * ±0.02°
Repeatability	±14” ±0.0039°	±25” ±0.0069°

Circulo 9

	Position 1 (inner)	Position 2 (outer)
Accuracy	±72” * ±0.02°	±72” * ±0.02°
Repeatability	±8” ±0.0022°	±13” ±0.0036°

* The specified accuracy corresponds to the encoder-related errors only. Installation-related errors such as runout and eccentricity are not considered. For more details see Encoder accuracy.

Functions

Encoder Position 1 (inner)
Mounted on	Configuration 1: joint Configuration 2: motor
Functions	Configuration 1: position Configuration 2: position / velocity / commutation

Encoder Position 2 (outer)
Mounted on	Configuration 1: motor Configuration 2: -
Functions	Configuration 1: velocity / commutation Configuration 2: -

Magnetic data

Parameter
Magnetic field strength at the surface of the chip	15 - 100 kA/m
Operating magnetic field frequency	max 7 kHz
External magnetic field	max 20 mT