Synapticon SOMANET Circulo 7 and 9 Servo Drives Review: Specs, Price and Applications
Updated: 4 days ago
SOMANET Circulo packages a servo drive around a hollow center for integration into robot joints and smart actuators. Circulo 7 and Circulo 9 have different electrical capacity, central clearance and encoder resolution. Integrated encoder rings, a brake and extended Safe Motion functionality depend on the selected construction. The product is drive and sensing hardware for an engineered axis, not a complete robot joint with a motor and gearbox already included.
Quick Verdict
Consider Circulo when the joint architecture benefits from local drive electronics and a central cable route. Select the 7 or 9 from the actual continuous load, transient duty and mechanical envelope. In particular, the family’s 60 A RMS headline belongs to Circulo 9 peak phase current; it is neither Circulo 7 capability nor Circulo 9 continuous current.
Synapticon SOMANET Circulo 7 and 9 Servo Drives at a Glance
Specification | Details |
Circulo 7 current | 8 A RMS continuous; 24 A RMS peak; thermal mounting and load-cycle conditions apply |
Circulo 9 current | 20 A RMS continuous; 60 A RMS peak; thermal mounting and load-cycle conditions apply |
Published output-power maxima | 7: 250 W continuous / 750 W peak; 9: 630 W continuous / 1850 W peak |
Supply | 24–48 Vdc nominal; current documentation lists 58 V continuous maximum / 60 V peak |
Circulo 7 envelope | 72.2 mm outer diameter; 20 mm inner diameter; 21.3 mm height |
Circulo 9 envelope | 92.2 mm outer diameter; 40 mm inner diameter; 22.3 mm height |
Optional integrated feedback | 7: 19-bit absolute; 9: 20-bit absolute; one or two rings by variant |
Encoder variants | ECNN: no integrated encoder; ECAN: inner; ECBN: outer; ECDL: dual |
Safety scope | Standard STO/SBC versus SMM extended Safe Motion; exact hardware and firmware apply |
Price | Request a quote for size, encoders, brake, safety and integration scope |
Design and Engineering Assessment
Circulo 9 offers more current and central clearance, but it also occupies a larger joint envelope. The documented outer diameters are 72.2 and 92.2 mm, and the inner openings are 20 and 40 mm. Neither opening automatically qualifies a cable bundle for repeated articulation: routing and bend requirements still belong to the robot design.
Continuous phase current is 8 A RMS for Circulo 7 and 20 A RMS for Circulo 9 under the documented thermal conditions. Their 24 and 60 A RMS peak entries are transient operating capabilities. Do not copy the larger unit’s peak figure into the smaller unit’s specification or use it as sustained motor current.
The optional integrated encoders are 19-bit on Circulo 7 and 20-bit on Circulo 9. Resolution describes digital position increments, not joint accuracy. Ring installation, calibration, mechanical transmission and the load-position reference determine how useful those increments are in the machine.
The standard and SMM documentation describe different safety scopes. Standard STO/SBC does not imply the extended speed, stop or position functions of an SMM configuration. Some extended functions further depend on the Safe Motion generation and firmware. Specify the exact variant and intended safety function before selecting hardware.
Choose the Joint Envelope and Heat Path Together
A decentralized drive places power electronics near the motor and joint mechanics. Design the thermal contact and mounting surface at the same time as the mechanical package. A compact circular outline does not establish continuous full-current operation without the specified heat path.
Include encoder-ring clearances, phase connections, brake options and cable access in the joint model. The drive envelope is not the complete moving actuator envelope. A prototype that fits mechanically still needs a representative loaded thermal cycle.
Continuous,Peak and Supply Limits
Use RMS current consistently when comparing the selected motor and drive. Check the full repeated motion cycle and the supplier’s load-cycle conditions for peak operation. Peak output power and peak current are not independent guarantees of a specific shaft torque and speed.
The nominal supply range and maximum continuous and peak voltage are separate boundaries. Account for supply tolerance and regenerated energy from deceleration. A motor described broadly as a 60 V class device does not make sustained operation at 60 V an approved default for the drive.
Encoder Rings and Dual-Loop Architecture
Select ECNN, ECAN, ECBN or ECDL according to the intended feedback arrangement. The standard ECNN variant does not contain integrated encoder rings. Decide whether each feedback reference measures motor motion or the joint output and use the appropriate physical installation.
For dual feedback, establish the mechanical relationship between the measured positions and validate the loop configuration. The second encoder can support a more useful load reference, but it does not automatically eliminate transmission compliance, calibration error or every source of output motion error.
Brake and Functional Safety Scope
Integrated brake hardware is optional, and safe brake control is a control function rather than a promise that every order includes a correctly sized mechanical brake. Match the brake’s holding duty and electrical requirements to the actual axis and selected hardware.
Use the applicable standard or SMM safety manual and certificate for the exact construction and firmware. Validate the complete machine’s stopping, holding and restart behavior. A certified drive function does not on its own establish a safe collaborative application or permit unrestricted human contact.
EtherCAT Commissioning and Acceptance
Match the controller, device description and firmware to the selected CiA 402 configuration. Establish feedback scale, direction, commutation and limits before tuning. The published EtherCAT rate is not a mechanical bandwidth or position-accuracy guarantee.
Use OBLAC tools and representative motion to evaluate loaded settling, standstill behavior, temperatures and fault response. Compare Circulo with other local-drive architectures on installed mass, envelope, heat path, safety scope and service access, with the same acceptance requirements.
Applications and Selection
Robot-joint and smart-actuator integration requiring a hollow local-drive package
For Synapticon SOMANET Circulo 7 and 9 Servo Drives, define the actual machine duty before selecting an ordering configuration. Include the required operating point, available installation space, environment and control interfaces. The specification table describes the product or family; the surrounding machine determines which of those features matters for the intended job.
Price and Value
Price: Request a quote for the exact configuration. Compare the product, compatible control equipment, required mechanical parts, cabling and commissioning as one installed system. A component price alone does not represent the cost of a working automation axis.
Evaluate an alternative against the same duty and acceptance criteria. Match the continuous operating requirement first, then compare transient capability, feedback, mechanical fit and support. This avoids choosing between superficially similar products whose ratings describe different operating conditions.
Pros and Cons
Advantages
Hollow circular package supports integration close to a robot joint
Two sizes provide explicit electrical and mechanical tradeoffs
Configurable integrated feedback and brake arrangements support different axis designs
Limitations
Peak family current is not continuous current or a rating shared by both sizes
Encoder resolution does not establish joint accuracy
Thermal path and exact safety, brake and encoder variants require engineering
Who Should Consider Synapticon SOMANET Circulo 7 and 9 Servo Drives?
robot and machine builders engineering a documented decentralized servo axis
Synapticon SOMANET Circulo 7 and 9 Servo Drives FAQ
Is Circulo a complete joint actuator?
No. It provides drive and configured sensing, brake and safety functions for integration. Motor, transmission, structure and complete axis performance must be specified separately.
Can Circulo 7 deliver 60 A RMS?
The cited table lists 8 A RMS continuous and 24 A RMS peak for Circulo 7. The 60 A RMS peak entry belongs to Circulo 9.
Is Circulo 9 rated for 60 A RMS continuously?
No. Its documented continuous phase current is 20 A RMS under the thermal conditions; 60 A RMS is the peak entry.
Does every variant include two encoders?
No. ECNN has no integrated encoder rings; ECAN, ECBN and ECDL provide different integrated feedback arrangements.
Does 20-bit feedback mean 20-bit joint accuracy?
No. Resolution, sensor accuracy, calibration, installation and mechanical output accuracy are different quantities.
Are all Safe Motion functions standard?
No. Distinguish the standard STO/SBC scope from SMM extended functions and the exact hardware and firmware requirements.
Is a mechanical brake always supplied?
No. Integrated brake hardware is optional. Confirm the ordered brake and its suitability for the axis rather than inferring it from brake-control capability.
What should the quotation define?
Specify size, load cycle, current convention, bus conditions, heat path, encoder arrangement, brake, safety variant, controller and firmware, mounting and acceptance requirements.
Prices are indicative and may change. Confirm the final configuration, commercial terms and delivery schedule before ordering.
