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PCB-mount drive

Synapticon SOMANET Circulo PCB-mount drive

Ring-shaped servo drives (Circulo 7 and 9) that sit inside a robot joint around the hollow shaft, up to 60 V and 60 A rms, with up to two integrated 20-bit absolute encoders, EtherCAT at up to 4 kHz and more than ten SIL3 / PL e safety functions.

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Pricing and availability

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Need Synapticon parts, a replacement or a suitable alternative? Send us a part number, or tell us what the machine needs to do. Our UK engineers will come back with the right product, pricing, lead time and delivery, whether that is the original part, a checked alternative or a complete axis.

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Select every part you need and answer the questions an applications engineer would ask. Our engineers use your specification to come back with the right products, pricing and lead times. You see your summary before we ask for any details.

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  1. 1Products
  2. 2Performance
  3. 3Environment
  4. 4Volumes
  5. 5Your spec
Step 1 of 5

What are you specifying?

Select everything you need. A motor, drive and gearbox can be specified together as one axis.

1 selected: Servo drive

Key specifications

Voltage (max)60 V
Outer diameter (max)92 mm
Data / busEtherCAT, FSoE
Feedbackup to two integrated absolute encoders, optional battery-backed multi-turn
FieldbusEtherCAT (CiA 402), up to 4 kHz
Current (max)60 A
Resolution (max)20 bit
SizesCirculo 7 (72 mm), Circulo 9 (92 mm)
SafetySTO, SBC, SS1, SS2, SLS and more; SIL3 / PL e

Summarised in our own words from Synapticon GmbH's published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1

Notes on this data

Page inconsistent on whether 72/92 mm are diameters or radii; drawings label inner radii 20 and 40 mm. Current is RMS; continuous vs peak not separated.

Specify Motion is not affiliated with Synapticon GmbH. Synapticon and SOMANET Circulo are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.

Synapticon SOMANET Circulo replacement and alternative options

Use these supply-network options as a starting point for an engineering check. We can also help source the original Synapticon part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.

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 maximumSOMANET CirculoFlexPro Digital Servo Drives (FE, FX, …
Continuous current60 A100 A meets or exceeds
Peak current—200 A
Limited published data: 1 figure compared

AMC's analogue servo drives for centralised control schemes: set up with DIP switches and potentiometers, commanded by +/-10 V or PWM. They span 10-400 VDC and 45-265 VAC, up to 150 A continuous and 250 A peak, in PCB, panel and vehicle formats. PCB extended-environment parts run -40 to +85 C.

Published maximumSOMANET CirculoAxCent Analogue Servo Drives (AB, AZ, …
Continuous current60 A150 A meets or exceeds
Peak current—250 A
Limited published data: 1 figure compared

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 maximumSOMANET CirculoDigiFlex Performance Servo Drives (DP,…
Continuous current60 A150 A meets or exceeds
Peak current—250 A
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.

Typical applications

Robot jointsCobotsHumanoid robots

What a PCB-mount drive is

A PCB-mount servo drive is a compact servo drive module designed to be soldered or plugged into a host circuit board, rather than mounted in a cabinet. It contains the power stage and control loops for brushless, brushed or stepper-style motors, with interfaces such as CANopen, EtherCAT, SPI or analogue. Some versions are supplied with evaluation or carrier boards. Very high power density lets them fit inside robots, medical devices and instruments.

When engineers choose a PCB-mount drive

Choose a PCB-mount drive when the motor control must be embedded in the product, such as surgical robots, exoskeletons, AGVs, drones and laboratory instruments. It saves space and weight and integrates with the host board. The trade-offs are design responsibility and thermal management: the host board must provide heatsinking, connectors, EMC and protection. For machines with space for cabinets, packaged drives are simpler.

How to specify the Synapticon SOMANET Circulo

Send these with your enquiry and an engineer can confirm the right SOMANET Circulo variant or an equivalent:

  • Supply voltage (V DC)
  • Continuous and peak current (A)
  • Motor and feedback type
  • Interface: CANopen, EtherCAT, SPI or analogue
  • Size and mounting (mm)
  • Thermal path and heatsinking
  • Safety functions and approvals

Common mistakes to avoid

  • Ignoring the thermal path on the host board
  • Not designing EMC filtering and protection
  • Assuming evaluation board performance in a sealed product
  • Leaving out testing for safety and medical approvals

Synapticon SOMANET Circulo: frequently asked questions

Can you help replace Synapticon SOMANET Circulo or source the original?

Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including supply-network options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.

What is the Synapticon SOMANET Circulo?

Ring-shaped servo drives (Circulo 7 and 9) that sit inside a robot joint around the hollow shaft, up to 60 V and 60 A rms, with up to two integrated 20-bit absolute encoders, EtherCAT at up to 4 kHz and more than ten SIL3 / PL e safety functions. Published series figures include voltage 60 V, outer diameter 92 mm, current 60 A, resolution 20 bit. It is made by Synapticon GmbH; Specify Motion can help source it or propose an equivalent.

Who makes the Synapticon SOMANET Circulo?

The Synapticon SOMANET Circulo is made by Synapticon (Synapticon GmbH) and is listed here for engineers comparing options. Specify Motion is not affiliated with Synapticon GmbH; brand names are used only to identify the product.

What is the voltage of the Synapticon SOMANET Circulo?

The published series maximum voltage is 60 V. Individual models and sizes in the SOMANET Circulo 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 Synapticon SOMANET Circulo?

We can assess suitable replacement options. On published figures, ADVANCED Motion Controls FlexPro Digital Servo Drives (FE, FX, FM, FD, FMP; Micro and Mini sizes) and ADVANCED Motion Controls AxCent Analogue Servo Drives (AB, AZ, AV, B, AVB) are options to assess from our supply network. An engineer confirms the fit against your application before recommending anything.

What is the benefit of a PCB-mount servo drive?

A PCB-mount drive puts motor control inside the product, saving space, weight and cabling. It integrates with the host electronics and can be very power-dense. The host board designer takes on thermal, EMC and protection design, so evaluation boards are often used first.

How is heat removed from a PCB-mount drive?

Heat is usually conducted through the drive's base or pins into the host board and a heatsink or chassis. Copper area, thermal interface materials and airflow all matter. Continuous current ratings often assume specific heatsinking, so check the conditions in the datasheet.

Further reading: How to select a pcb mount servo drive · How to select a servo drive · Servo drives

Other pcb-mount drive series

Engineer support

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Tell us how you use the Synapticon SOMANET Circulo: the load, speed, duty and environment. Our engineers will confirm whether it is still the right part, find it for you, or propose an alternative that fits better.

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How it works

From enquiry to delivery

Send a part number or describe the application. Our engineers take it from there: the right product, a clear quotation, and delivery and support arranged.

  1. Tell us what you needSend a part number, or configure the application, quantities and timing.
  2. An engineer reviews itWe check the specification and find the original part, a checked equivalent or a complete axis.
  3. Receive your quotationProducts, pricing, lead time and compatibility notes in one reply.
  4. Order and deliveryWhen you are happy, the order is placed and delivery and after-sales support are arranged.