How to Select the Right EtherCAT Integrated Motor for Your Application: Key Parameters Explained

The industrial automation landscape has undergone a paradigm shift over the past decade. Traditional motion control systems, which relied on separate controllers, drives, cables, and motors, are rapidly being replaced by compact, intelligent, and highly integrated solutions. At the forefront of this transformation is the EtherCAT Integrated Motor – a device that combines a brushless DC or permanent magnet synchronous motor, a servo drive, a motion controller, and an EtherCAT slave interface into a single mechanical housing.

But why has the EtherCAT Integrated Motor become so popular? The answer lies in three words: simplicity, performance, and cost. By eliminating the need for a separate drive cabinet, reducing wiring from dozens of cables to a single EtherCAT daisy‑chain, and enabling real‑time synchronisation with microsecond accuracy, this integrated approach is revolutionizing machine building. However, selecting the right EtherCAT Integrated Motor for a specific application is not trivial. Engineers must evaluate dozens of parameters – from torque curves and thermal behaviour to EtherCAT cycle times, distributed clock capabilities, and CiA 402 profile support.

This comprehensive guide, exceeding 15,000 words, walks you through every critical selection parameter. Whether you are designing a high‑speed pick‑and‑place robot, a multi‑axis packaging machine, an automated guided vehicle, or a precision medical device, the principles outlined here will help you make an informed, future‑proof decision. We will cover mechanical, electrical, communication, software, environmental, safety, and economic aspects, complete with real‑world examples, comparison tables, selection checklists, and troubleshooting tips.

Part 1: Understanding the EtherCAT Integrated Motor – Core Concepts

1.1 What Exactly Is an EtherCAT Integrated Motor?

An EtherCAT Integrated Motor is a mechatronic device that integrates four traditional components:

• Electric motor (usually a 3‑phase synchronous servo motor or a stepper motor with closed‑loop control)
• Power stage (inverter with MOSFETs or IGBTs)
• Motion controller (position, velocity, or torque loop)
• EtherCAT slave controller (ESC) for real‑time fieldbus communication

Unlike a standard servo system where the drive resides in a control cabinet and connects to the motor via a thick power cable, the integrated motor mounts directly on the machine frame. Only two cables are typically required: a 24‑48 V DC or 230 V AC power cable (depending on the model) and an EtherCAT communication cable (Ethernet CAT5e/6). Some designs also include a third cable for an external holding brake or I/O, but many integrate the brake control inside the motor.

1.2 Why EtherCAT? The Communication Backbone

EtherCAT (Ethernet for Control Automation Technology) is a real‑time industrial Ethernet protocol developed by Beckhoff. It stands out for:

• Extremely short cycle times (down to 31.25 µs for pure I/O, 125 µs for servo axes)
• Distributed clocks that synchronise all slaves with <1 µs jitter
• Line, ring, or star topologies with up to 65535 devices
• Full compatibility with standard Ethernet (physical layer)
• High efficiency – a single frame can process data for many slaves on the fly

When integrated into a motor, EtherCAT eliminates the need for a separate real‑time backbone. The EtherCAT Integrated Motor becomes a true plug‑and‑play node on a high‑performance network.

1.3 Comparison with Traditional Servo Systems

1.4 Typical Applications

The EtherCAT Integrated Motor shines in applications where space is constrained, wiring must be minimised, and real‑time synchronisation is critical. Examples include:

• Packaging machinery (flow wrappers, cartoners, labelling machines)
• Pick‑and‑place robots (delta robots, SCARA, gantries)
• Semiconductor handling (wafer robots, aligners)
• Medical devices (syringe pumps, patient positioning tables)
• Printing presses (electronic gearing for colour registration)
• Automated guided vehicles (drive wheels, lift axes)
• Laboratory automation (liquid handlers, plate movers)

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Part 2: Mechanical Selection Parameters

The mechanical integration of an EtherCAT Integrated Motor is often the first and most visible constraint. If the motor does not physically fit or cannot deliver the required torque at the required speed, no amount of communication sophistication will save the design.

2.1 Frame Size and Mounting Flange

Most integrated motors follow either:

• NEMA standards (NEMA 17, 23, 34, 42) – common in North America and for stepper‑based integrated motors.
• Metric (ISO) standards (40 mm, 60 mm, 80 mm, 110 mm, 130 mm square or round flanges) – prevalent in European and Asian servo designs.

Selection criteria:

• Available mounting space: measure the clearance around the intended mounting point. Allow at least 10 mm for cable bending radius.
• Bolt hole pattern: match the existing machine interface or design a custom bracket.
• Shaft diameter and keyway: ensure compatibility with the load coupling, pulley, or gearbox.

Tip: Many EtherCAT Integrated Motor vendors provide 3D CAD models (STEP, IGES) on their websites. Download these and perform a virtual assembly before ordering.

2.2 Shaft Configuration

• Solid shaft with key – highest torque transmission, best for heavy loads.
• Solid shaft with flat – for smaller motors, easier alignment.
• Hollow shaft – allows cables, air, or light beams to pass through the motor centre. Ideal for rotary indexing tables or cable management in robots.
• Through‑shaft (extended on both ends) – for mounting encoders or brakes externally.

Example: In a delta robot’s forearm, a hollow‑shaft EtherCAT Integrated Motor can route pneumatic tubing directly to the end effector, reducing external hose clutter.

2.3 Holding Brake (Spring‑Applied, Electrically Released)

Many applications require the motor to hold position when power is removed (vertical axes, Z‑lifts, safety stops). An integrated holding brake is an optional feature that adds axial length and cost.

Brake selection parameters:

• Static torque rating – must exceed the maximum external load torque (including gravity) by a factor of 1.5 (safety factor).
• Response time – typically 10‑50 ms from brake release command to full release.
• Voltage – 24 V DC is standard; some motors provide brake control via the EtherCAT power supply.
• Backlash – integrated brakes are usually zero‑backlash (spring‑driven friction plate).

Important: When using an EtherCAT Integrated Motor with a brake, the drive automatically sequences the brake release after the motor current is established. Do not rely on an external PLC to control the brake directly unless the motor datasheet explicitly allows it.

2.4 Inertia Matching

Inertia mismatch is a common cause of poor dynamic performance. The total load inertia reflected to the motor shaft (J_load) should be within a certain ratio of the motor’s rotor inertia (J_motor).

• Rule of thumb: J_load / J_motor ≤ 5 for general purpose, ≤ 3 for high‑dynamic applications, and ≤ 1 for ultra‑precision positioning.
• Why it matters: High inertia mismatch forces the motor to generate large acceleration torques, leading to overshoot, longer settling times, and potential instability.

How to calculate reflected inertia:

For a direct drive (no gearbox): J_load = J_actual load.

For a belt drive: J_load = m * (r)^2, where m = mass (kg), r = pulley radius (m).

For a leadscrew: J_load = m * (p/(2π))^2, where p = screw pitch (m/rev).

**Most EtherCAT Integrated Motor datasheets include rotor inertia values. Use these to compute the ratio early in the selection process.

2.5 Mechanical Overload Protection

Unlike a separate drive that might have configurable current limits, an integrated motor’s drive electronics are built into the motor housing. If a mechanical jam occurs, the internal power stage can overheat quickly. Consider:

• Torque limit setting – programmable via EtherCAT (CiA 402 object 0x6072). Set this to a safe value below the motor’s stall torque.
• External torque limiter – mechanical slip clutch for very high‑risk applications (e.g., screwdriving, press‑fit operations).
• Software monitoring – use the motor’s “torque actual value” (0x6077) in the PLC to detect overload and stop the axis.

2.6 Axial and Radial Load Capacities

Every EtherCAT Integrated Motor has maximum permissible axial (thrust) and radial (side) loads on the output shaft, specified for a given bearing life (e.g., L10 20,000 hours).

• Radial load – caused by belt tension, gear overhang, or pulley weight.
• Axial load – from pushing/pulling against a leadscrew or direct thrust.

Selection rule: Never exceed 50% of the rated load if continuous operation is expected. For high‑load applications, consider adding an external support bearing (e.g., pillow block) and coupling the motor through a flexible coupling to avoid overloading the motor bearings.

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Part 3: Electrical and Power Parameters

The EtherCAT Integrated Motor is both a load (it consumes power) and a source of electromagnetic interference (EMI). Understanding its electrical specifications is crucial for power supply sizing, thermal management, and EMC compliance.

3.1 Supply Voltage and Power Range

Integrated motors are available in three voltage classes:

Important considerations:

• Ripple and noise: A poorly regulated DC supply can cause torque ripple and EtherCAT communication errors. Use a PELV (Protective Extra Low Voltage) power supply with <5% ripple.
• In‑rush current: Integrated motors contain large capacitors. When first powered, they may draw 10‑20x rated current for a few milliseconds. Size the power supply accordingly or use a soft‑start circuit.
• Shared supplies: If multiple EtherCAT Integrated Motor units share one power supply, ensure the supply’s peak current rating exceeds the sum of all motors’ peak currents (not RMS). Add 20% headroom.

3.2 Rated vs. Peak Torque and Current

Every motor datasheet provides two torque values:

• Rated torque (continuous) – torque that can be produced indefinitely without exceeding the motor’s thermal limit (typically at 25°C ambient, with natural convection or specified heatsinking).
• Peak torque (short‑term) – torque available for up to 2‑5 seconds (duty cycle dependent) before the drive limits current to protect the electronics.

Peak torque is usually 2‑3 times rated torque. This ratio (peak/rated) determines the motor’s ability to handle acceleration, deceleration, and occasional overloads.

Example: A pick‑and‑place robot requires 1.5 Nm continuous torque during the constant velocity phase, but 4 Nm during a 100 ms acceleration. Choose a motor with rated torque ≥1.5 Nm and peak torque ≥4 Nm. The peak/rated ratio must be at least 4/1.5 = 2.66.

3.3 Torque‑Speed Curve

The torque‑speed curve is the single most important graphical selection tool. It shows:

• Stall torque (torque at zero speed, limited by continuous current)
• Rated speed (speed at which rated torque is available; beyond this, torque drops due to back‑EMF)
• Maximum speed (mechanical limit or field‑weakening region)

Three operating zones:

1. Constant torque zone – from zero to rated speed. Full torque available.
2. Constant power zone (field weakening) – from rated speed to maximum speed. Torque decreases inversely with speed.
3. Intermittent zone – peak torque available for short periods.

How to use: Plot your load’s required torque vs. speed for the entire cycle (including acceleration and deceleration). Ensure that every point lies below the motor’s peak torque curve, and the RMS torque (calculated over the whole cycle) lies below the rated torque curve.

3.4 Back EMF and Winding Inductance

These parameters affect the drive’s ability to control current at high speeds:

• Back EMF constant (Ke) – expressed in V/krpm or V/rad/s. Higher Ke means more voltage is induced as speed rises, reducing the available voltage for current (torque) production.
• Winding inductance (L) – higher inductance smooths current ripple but slows down current response.

For EtherCAT Integrated Motor units operating at speeds above 3000 rpm, ensure that the supply voltage is at least 1.5 × (Ke × maximum speed + resistive drop). Otherwise, the motor may not reach the required speed.

3.5 Power Dissipation and Cooling

Because the drive electronics are inside the motor housing, heat generated by the power stage adds to the motor’s own I²R losses. Most integrated motors rely on:

• Natural convection – via the motor’s external surface (aluminium housing with fins). Rated torque is specified under these conditions.
• Forced air cooling – using a fan blowing over the motor (can increase continuous torque by 30‑50%).
• Liquid cooling – for very high power density (rare in integrated motors).

Derating factors:

• Ambient temperature > 40°C → reduce rated torque by 2‑5% per °C above 40.
• Mounting orientation: vertical mounting may reduce convection, requiring derating.
• Enclosed machine environment: if the motor is inside a sealed cabinet, rated torque may drop 20‑30%.

Always consult the motor’s thermal derating curves. If the application requires continuous operation near rated torque, consider a larger frame size or active cooling.

3.6 Electrical Noise and EMC

An EtherCAT Integrated Motor is a switching power converter (PWM frequency typically 16‑32 kHz). This generates conducted and radiated EMI that can affect nearby sensors and the EtherCAT communication itself.

Best practices:

• Use shielded EtherCAT cables with metal RJ45 connectors that make 360° contact to the shield.
• Connect the motor’s ground terminal (PE) directly to a star ground point.
• Install ferrite cores on the power input cable (one turn through a ferrite ring).
• Keep power and EtherCAT cables at least 10 cm apart; cross them at 90° if unavoidable.
• Verify CE/UL EMC compliance of the selected motor. Many vendors offer pre‑tested EMC kits.

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Part 4: EtherCAT Communication and Real‑Time Parameters

The “EtherCAT” part of the EtherCAT Integrated Motor is what enables high‑performance synchronisation and Industry 4.0 connectivity. Selecting the right communication features is as important as selecting torque and speed.

4.1 EtherCAT Slave Controller (ESC) Generation

The ESC is a dedicated hardware chip (or integrated IP core) that processes EtherCAT frames on the fly. Key features vary by generation:

For most applications, an EtherCAT Integrated Motor with an ESC20 or newer is sufficient. Gigabit (ESC30) is rarely needed because servo cycles rarely exceed 1 kHz.

Check: The ESC should support Distributed Clocks (DC) – this is non‑negotiable for multi‑axis synchronisation.

4.2 Cycle Time (Communication Period)

The cycle time is the interval at which the EtherCAT master sends new setpoints (position, velocity, torque) to the motor. Supported cycle times vary:

• 125 µs – for very high‑speed applications (laser scanning, high‑dynamic pick‑and‑place)
• 250 µs, 500 µs, 1 ms – common for most servo axes
• 2 ms, 4 ms – for slow moving or less demanding axes

Rule: The cycle time must be shorter than the fastest mechanical time constant of the load. If the load can change significantly within one cycle, the motor will lag.

Practical advice: Start with 1 ms for general automation. Only reduce to 250 µs if you have verified that the master can handle the increased computational load and the network is not saturated.

4.3 Distributed Clocks (DC) and Synchronisation Error

Distributed clocks allow all EtherCAT Integrated Motor slaves to share the same system time, typically derived from the first slave (reference clock). The synchronisation error (jitter) between motors should be:

• <1 µs for high‑performance electronic gearing (printing, flying shear)
• <5 µs for most coordinated motion (robotics, packaging)
• <20 µs for simple indexing

How to verify: After commissioning, use the master’s diagnostic tools (e.g., TwinCAT’s DC measurement) to read the propagation delay and shift time. Some integrated motors also provide object 0x1C33 (Sync error) to monitor synchronisation quality.

4.4 CiA 402 Drive Profile Support

CiA 402 (CANopen drive profile over EtherCAT) is the standard that defines how to control a servo drive. An EtherCAT Integrated Motor must support the following mandatory objects:

• 0x6040 (Controlword) – start/stop, enable operation, fault reset.
• 0x6041 (Statusword) – ready, enabled, fault, target reached.
• 0x6060 (Modes of operation) – select position, velocity, torque, or homing mode.
• 0x607A (Target position) – for cyclic synchronous position mode.
• 0x6081 (Profile velocity) – for profile position mode.

Optional but highly desirable:

• 0x60B8 (Touch probe) – for registration (high‑speed position capture).
• 0x60C5 (Interpolated position record) – for advanced trajectory generation.
• 0x60F2 (Position offset) – for additive superposition (master‑slave).

Warning: Some low‑cost integrated motors only support “Profile Position Mode” (PP), not “Cyclic Synchronous Position Mode” (CSP). CSP is required for real‑time trajectory generation by the master. Verify which modes are supported before purchasing.

4.5 Process Data Objects (PDOs) and PDO Mapping

PDOs define which data are exchanged cyclically. A typical mapping for an EtherCAT Integrated Motor in CSP mode:

RxPDO (Master → Motor):

• Controlword (2 bytes)
• Target position (4 bytes, integer or float)
• Target velocity (4 bytes) – optional
• Torque offset (2 bytes) – optional

TxPDO (Motor → Master):

• Statusword (2 bytes)
• Actual position (4 bytes)
• Actual velocity (4 bytes) – optional
• Actual torque (2 bytes) – optional
• Digital inputs (1 byte) – if integrated I/O exists

Limitation: Most integrated motors have a maximum PDO length of 20‑32 bytes. Do not attempt to map more data than the ESC’s buffer can handle.

4.6 CoE (CANopen over EtherCAT) vs. SoE (SERCOS over EtherCAT)

• CoE – by far the most common. Uses CANopen object dictionary. All major PLCs (Beckhoff, Siemens, Omron, Codesys) support CoE.
• SoE – used by some legacy drives (e.g., IndraDrive). Rare in integrated motors.

Recommendation: Insist on CoE with CiA 402. It ensures compatibility with almost any EtherCAT master.

4.7 EtherCAT Conformance Test

The EtherCAT Technology Group (ETG) offers a conformance test tool. An EtherCAT Integrated Motor that has passed the official conformance test will have a certificate number. Always ask for the conformance test report. Non‑conformant devices may cause random network errors, lost frames, or synchronisation drift.

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Part 5: Software, Configuration, and Diagnostics

Selecting the hardware is only half the story. The ease with which you can configure, tune, and diagnose the EtherCAT Integrated Motor dramatically impacts project timelines and machine uptime.

5.1 ESI (EtherCAT Slave Information) File

Every EtherCAT slave must be described by an XML file (ESI) that contains:

• Vendor ID and product code
• PDO mapping information
• Sync manager configuration
• DC settings
• Standard objects (CiA 402)

Selection tip: Choose a motor vendor that provides an up‑to‑date, well‑commented ESI file. Some vendors supply generic files that are missing key objects. Test the ESI with your master’s configuration tool before ordering multiple units.

5.2 Configuration Software

Most EtherCAT Integrated Motor manufacturers offer proprietary Windows‑based tools for:

• Initial setup – set motor parameters (current limits, pole pairs, encoder resolution).
• Autotuning – measure load inertia, auto‑adjust position/velocity gains.
• Oscilloscope – record real‑time traces of position error, torque, etc.
• Firmware updates – flash new firmware via EtherCAT (FoE – File over EtherCAT).

Examples: Beckhoff TwinCAT (free for configuration), JVL’s MacTalk, Moons’ SSTEP, Ingenia’s MotionLab.

What to look for: The tool should support saving/restoring parameters to a file, exporting traces to CSV, and generating a “tuning report” for documentation.

5.3 Autotuning and Servo Gains

Modern integrated motors include advanced autotuning algorithms that measure the load’s inertia, friction, and resonance frequencies. After autotuning, the drive sets:

• Kp (proportional gain) – stiffness
• Ki (integral gain) – steady‑state error elimination
• Kd (derivative gain) – damping
• Velocity feedforward – reduces following error

Selection criterion: Ensure the motor’s autotuning works over EtherCAT (i.e., the master can trigger tuning by writing to an object). Some low‑end motors require a separate USB connection for tuning, which is inconvenient.

5.4 Diagnostic Capabilities

A well‑designed EtherCAT Integrated Motor provides extensive diagnostic data via CoE objects:

Tip: Map the statusword (0x6041) and actual position (0x6064) to your PLC’s cyclic data. Then log these values to identify intermittent issues (e.g., mechanical backlash, EMI spikes).

5.5 Firmware Update Mechanism

Over the product lifetime, vendors release firmware updates to fix bugs or add features. The EtherCAT Integrated Motor should support FoE (File over EtherCAT) for remote updates without opening the control cabinet.

Checklist:

• Does the motor have a bootloader that accepts FoE updates?
• Is the update process documented?
• Can you roll back to a previous firmware version?

Avoid motors that require physical disassembly to update firmware – this is a red flag for long‑term support.

5.6 Compatibility with Your Master (PLC)

Not all EtherCAT masters are created equal. The master must support:

• CoE and CiA 402 (most do)
• Distributed clocks (some low‑cost soft‑PLCs omit this)
• Dynamic PDO assignment (allows changing PDO mapping on the fly – nice to have)
• Sync manager 2/3 configuration (mandatory for cyclic operation)

Test before buying: If possible, request a demo unit and connect it to your actual master (e.g., TwinCAT, Codesys, Omron Sysmac, Siemens S7‑1500 with EL6631). Verify that the motor transitions to Operational state and responds to cyclic commands.

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Part 6: Environmental and Mechanical Installation Considerations

The EtherCAT Integrated Motor will often be mounted in harsh environments – near liquids, dust, vibrations, or extreme temperatures. Selecting the appropriate protection level and installation method is critical for reliability.

6.1 IP Rating (Ingress Protection)

Important: An IP65/IP67 EtherCAT Integrated Motor requires IP65/IP67 rated connectors and cables. The motor alone is useless if water enters through the RJ45 jack. Specify motors with sealed M12 connectors (D‑coded for EtherCAT, A‑coded for power) instead of open RJ45.

6.2 Operating Temperature and Humidity

• Standard range: 0°C to +40°C, 5‑95% RH non‑condensing.
• Extended range: –20°C to +60°C (requires derating above 40°C).
• Storage temperature: –25°C to +85°C.

Special considerations:

• Cold environments – below 0°C, lubricants thicken, increasing friction. Some motors offer low‑temperature grease.
• Hot environments – above 40°C, rated torque must be derated. The motor’s internal electronics may have a lower max temperature (e.g., 85°C on the power stage) than the motor windings (130°C). The limiting component is usually the electrolytic capacitors (105°C typical).

Calculation: For ambient T > 40°C, derate continuous torque by 2% per °C. Example: at 55°C, derate by 30%, so a 2 Nm motor provides only 1.4 Nm continuous.

6.3 Vibration and Shock Resistance

Machines like presses, stamping equipment, or mobile robots generate significant vibration. EtherCAT Integrated Motor datasheets should specify:

• Vibration – typically 0.5‑2 g (5‑200 Hz) for operation.
• Shock – 5‑10 g (11 ms half‑sine) non‑operating.

For high‑vibration applications (e.g., vibrating conveyors), choose a motor with:

• Conformal coating on the PCB to prevent component loosening.
• Locked connectors (screw‑type or bayonet).
• No electrolytic capacitors (use ceramic or tantalum) – rare but available.

6.4 Chemical Resistance

In food, pharmaceutical, or chemical plants, the motor housing may be exposed to cleaning agents (e.g., chlorine, caustic soda, alcohol). Standard aluminium housings with anodised finish resist mild chemicals. For aggressive environments, specify:

• Stainless steel housing (304 or 316L)
• FDA‑approved lubricants (if the motor has internal gearing)
• Smooth, crevice‑free surfaces to prevent bacterial growth

6.5 Mounting Orientation and Heat Dissipation

• Horizontal shaft – best for natural convection (air flows along fins).
• Vertical shaft (motor above load) – acceptable; heat rises through the housing.
• Vertical shaft (motor below load) – worst; heat accumulates near the end cap where electronics reside. Derate torque by 10‑20%.

Installation tip: If mounting vertically, ensure the motor’s ventilation holes (if any) are not facing upward to avoid dust and liquid entry. Many integrated motors are totally enclosed (TE) – no ventilation holes – which simplifies orientation but reduces heat dissipation.

6.6 Cable Management and Bend Radius

The EtherCAT and power cables connected to the EtherCAT Integrated Motor will move if the motor is on a robot arm or linear actuator. Use flexible cables rated for continuous flexing (minimum 10 million cycles). The bend radius should be at least 10× the cable diameter for moving applications, 5× for static.

Avoid: Tight cable ties that compress the cable jacket, and sharp edges that can abrade the shield.

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Part 7: Safety and Compliance

Modern machinery must comply with regional safety standards (CE, UL, UKCA, etc.). The EtherCAT Integrated Motor you select must not compromise machine safety.

7.1 Safe Torque Off (STO)

STO is a functional safety input that removes power from the motor’s power stage without removing the control supply. When STO is active, the motor cannot produce torque.

STO categories:

• Type 1 (basic) – two independent channels; meets ISO 13849‑1 PL d or IEC 61508 SIL 2.
• Type 2 (advanced) – diagnostics and cross‑monitoring; PL e / SIL 3.

Important: STO alone does not stop the motor if the load is external (e.g., gravity). For vertical axes, you also need a holding brake that is activated when STO is triggered.

Integration: The STO signals (e.g., 24 V DC inputs) are usually on a separate connector. Some EtherCAT Integrated Motor models support “FSoE” (FailSafe over EtherCAT) – safety communication over the same cable, eliminating separate safety wiring.

7.2 Other Safety Functions

Beyond STO, some integrated motors offer:

• SBC (Safe Brake Control) – monitors the holding brake.
• SLS (Safe Limited Speed) – prevents the motor from exceeding a safe speed.
• SS1/SS2 (Safe Stop 1/2) – controlled deceleration then STO.

Selection advice: If your application requires PL d or higher, choose a motor with integrated safety (certified by TÜV or similar). Retrofitting external safety relays is possible but adds cost and complexity.

7.3 CE, UL, and Other Marks

• CE marking – mandatory for sale in Europe. Indicates compliance with EMC, Low Voltage, and Machinery Directives.
• UL (Underwriters Laboratories) – required for North America (US and Canada). Look for “UL Recognized” (UR) or “UL Listed”.
• UKCA – UK equivalent of CE.
• CCC – China Compulsory Certificate.

Check: The motor’s power supply must also be UL/CE certified. A CE‑marked motor alone is not sufficient – the entire machine must be CE‑marked.

7.4 Functional Safety Documentation

If you are building a safety‑related system, you will need:

• Safety manual – describes failure modes, response times, and proof test intervals.
• PFH (Probability of Dangerous Failure per Hour) and MTTFd values.
• Architecture – e.g., category 3, 4 per ISO 13849‑1.

Request these documents before selecting a motor for a safety application. Many low‑cost integrated motors do not provide any safety documentation.

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Part 8: Cost, Availability, and Lifecycle

No selection is complete without considering commercial factors. A technically perfect EtherCAT Integrated Motor that costs twice the project budget or has a 6‑month lead time is not a viable choice.

8.1 Total Cost of Ownership (TCO)

Compare not only the purchase price but also:

Conclusion: The EtherCAT Integrated Motor often has a higher upfront price but a significantly lower TCO, especially in multi‑axis machines.

8.2 Vendor Lead Times and Stock Availability

Check the vendor’s typical lead time:

• Standard models – 1‑4 weeks (e.g., Moons’, Leadshine)
• Custom models – 8‑12 weeks (e.g., Elmo, Ingenia with special windings)
• High‑demand periods – extend lead times unpredictably

Recommendation: For prototyping, buy from distributors that stock common models (e.g., NEMA 23, 48 V, 2‑3 Nm). For production, negotiate a consignment stock or a guaranteed lead time.

8.3 Product Lifecycle and Obsolescence

Industrial machines often run for 10‑20 years. Select an EtherCAT Integrated Motor from a vendor with a clear lifecycle policy:

• Active – full support, production continues.
• Mature – no new features, but still available.
• End‑of‑Life (EOL) – last‑time buy, support limited.

Avoid EOL parts. For safety‑critical machines, prefer vendors that guarantee availability for 10 years.

8.4 Support and Documentation Quality

Evaluate the vendor’s technical support:

• Is the datasheet complete? (torque‑speed curves, dimensional drawings, PDO mapping table, example ESI files)
• Is there a public knowledge base or forum?
• Do they offer phone/email support in your time zone?
• Can they provide a sample motor for testing?

Red flags: No downloadable ESI file, missing thermal data, no clear return policy.

8.5 Open Source vs. Proprietary Ecosystem

Some integrated motors are designed to work only with a specific master (e.g., Beckhoff motors with TwinCAT). Others are truly open and work with any CiA 402 compliant master.

Our advice: Choose open standard (CoE, CiA 402) even if you currently use a specific PLC brand. This preserves your ability to change the master in the future without replacing motors.

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Part 9: Step‑by‑Step Selection Process

Now that we have covered all parameters, let’s condense them into a practical 10‑step selection process for an EtherCAT Integrated Motor.

Step 1: Define the Motion Profile

For each axis, determine:

• Maximum speed (rpm or mm/s)
• Maximum acceleration/deceleration (rpm/s or m/s²)
• Load torque (continuous and peak)
• Duty cycle (percentage of time moving vs. stopped)
• Positioning accuracy (absolute and repeatability)

Step 2: Calculate Required Torque and Speed

Using the load’s inertia and friction, compute:

• Acceleration torque = (J_total) × α (angular acceleration)
• Running torque = friction + process torque
• Deceleration torque = (J_total) × α (usually negative, absorbed by the drive)
• RMS torque = sqrt( (T1²·t1 + T2²·t2 + …) / total cycle time )

The motor’s rated torque must be ≥ RMS torque. The peak torque must be ≥ max(acceleration torque, deceleration torque, peak process torque).

Step 3: Select Voltage and Frame Size

• Choose DC or AC based on available power and safety requirements.
• Select a frame size that provides at least 20% torque margin above the calculated RMS torque.
• Verify the physical dimensions fit.

Step 4: Verify Inertia Ratio

J_load / J_motor ≤ 5 (or ≤3 for high dynamics). If too high, consider a gearbox or a larger motor frame.

Step 5: Choose EtherCAT Features

• Minimum cycle time required (1 ms is safe for most).
• Distributed clocks – mandatory for multi‑axis.
• CiA 402 modes – at least CSP (Cyclic Synchronous Position).
• Check that the ESI file is available and conformance tested.

Step 6: Evaluate Environmental Compatibility

• IP rating required for the machine environment.
• Operating temperature range and derating.
• Vibration and chemical exposure.

Step 7: Check Safety Requirements

• Does the application need STO? SBC? SLS?
• What safety level (PLr, SIL) is required?
• Does the motor have certified safety functions?

Step 8: Review Software and Diagnostics

• Is there a configuration tool that works with your operating system?
• Does the motor support autotuning over EtherCAT?
• Can you read diagnostic objects (temperature, error history) from the PLC?

Step 9: Compare Vendors and Get Quotes

Create a shortlist of 2‑3 vendors that meet the technical specs. Request:

• Sample unit for testing (or at least a datasheet and ESI file)
• Pricing for prototype quantity and for 100‑500 units
• Lead time and availability

Step 10: Test Before Finalising

Order one unit and integrate it into a mock‑up of your machine. Run the actual motion profile. Measure:

• Following error (position lag)
• Temperature rise after 1 hour continuous running
• EtherCAT frame loss rate (should be 0)
• Noise and vibration

Only after successful testing should you commit to production quantities.

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Part 10: Case Studies – Real‑World Selection Examples

Case Study 1: High‑Speed Pick‑and‑Place Robot (Delta Robot)

Requirements:

• 4 axes (3 translation + 1 rotation)
• Cycle time: 0.3 seconds per pick (accelerate, move 300 mm, decelerate, pick, return)
• Max speed: 6000 rpm (after gear reduction)
• Peak torque: 8 Nm (during acceleration)
• Continuous torque: 2 Nm
• Ambient: 30°C, clean indoor

Selected motor: 48 V DC, NEMA 34 frame (86 mm), rated torque 2.5 Nm, peak torque 9 Nm, rotor inertia 1.2 kg·cm². Gearbox ratio 10:1. Inertia ratio = 3.8 (acceptable). EtherCAT cycle time 250 µs. STO included.

Result: The delta robot achieved 0.28 sec cycle time, well within spec. The integrated motors saved 70% of cabinet space compared to a traditional drive‑based design.

Case Study 2: Pharmaceutical Filling Machine (Rotary Indexing Table)

Requirements:

• 8 stations, each requires precise positioning ±0.05° at the fill station
• Index time: 0.5 sec per station (move, dwell 0.3 sec for filling)
• Load inertia very high (300 kg table)
• Torque at indexing: 15 Nm peak, 5 Nm continuous
• Environment: occasional washdown (IP65)

Selected motor: 230 V AC, 130 mm frame, rated torque 6 Nm, peak 18 Nm, with IP65 M12 connectors and a 100:1 harmonic drive gearbox (integrated into the motor as a “gear motor” version). EtherCAT cycle time 1 ms.

Challenges: The gearbox introduced 6 arcmin backlash. After tuning, the positioning error was 0.08° – slightly above spec. Solution: added a final fine‑positioning step with a slower speed. The integrated motor’s internal brake held the table during filling, eliminating an external brake.

Case Study 3: Automated Guided Vehicle (AGV) Drive Wheel

Requirements:

• 24 V DC (battery powered)
• 120 W continuous, 400 W peak for 2 seconds (climbing ramp)
• Max speed 1500 rpm
• Must communicate with vehicle controller via EtherCAT
• Operating temperature: –10°C to +50°C (warehouse, no HVAC)

Selected motor: 24 V DC, NEMA 23 (57 mm), rated torque 0.6 Nm, peak 2.4 Nm. Integrated drive with STO (required for safety in manned areas). Conformal coating for condensation protection.

Result: The AGV’s battery runtime improved by 15% because the integrated motor’s drive had regenerative braking, returning energy to the battery during deceleration. The EtherCAT network also carried diagnostics (wheel temperature, runtime) to the fleet management system.

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Part 11: Common Mistakes and How to Avoid Them

Even experienced engineers make errors when selecting an EtherCAT Integrated Motor. Here are the top 10 mistakes and their solutions.

Mistake 1: Ignoring the Torque‑Speed Curve at Higher Speeds

Problem: The motor seems to have enough rated torque, but at the required speed (e.g., 4000 rpm), the available torque drops significantly due to back‑EMF.

Solution: Always consult the torque‑speed curve at the exact operating speed, not just the stall torque.

Mistake 2: Forgetting the Brake for Vertical Axes

Problem: When power is removed, the Z‑axis drops, causing damage or injury.

Solution: Specify a motor with an integrated holding brake rated for the maximum static load multiplied by 1.5.

Mistake 3: Underestimating Inertia Mismatch

Problem: The motor can deliver the torque, but the system oscillates or overshoots.

Solution: Calculate the reflected inertia early. If the ratio exceeds 10, add a gearbox.

Mistake 4: Using Non‑Shielded EtherCAT Cables

Problem: Random communication errors, frame loss, and motor stalls.

Solution: Always use shielded, CAT5e or higher Ethernet cables with metal connectors. Ground the shield at both ends (but avoid ground loops – use star grounding).

Mistake 5: Overlooking the ESI File Compatibility

Problem: The master cannot parse the XML file, or PDO mapping does not match the manual.

Solution: Test the ESI file with your master before ordering. If problems occur, ask the vendor for an updated file.

Mistake 6: Mounting in a Sealed Box Without Derating

Problem: Motor overheats and shuts down after 20 minutes.

Solution: Derate continuous torque by 20‑30% when mounting in an enclosure. Provide forced air circulation.

Mistake 7: Assuming All EtherCAT Masters Support Distributed Clocks

Problem: The master does not enable DC, causing synchronisation drift between motors.

Solution: Verify DC support in the master’s datasheet. For soft‑PLCs, ask the vendor explicitly.

Mistake 8: Choosing a Motor Without STO When Required

Problem: The machine cannot be CE‑marked because the motor lacks safe torque off.

Solution: Identify safety requirements (risk assessment) before selecting the motor. If STO is needed, choose a certified motor.

Mistake 9: Not Planning for Firmware Updates

Problem: A bug in the motor’s firmware cannot be fixed without shipping the motor back.

Solution: Ensure FoE (File over EtherCAT) is supported and you have the update tool. Keep a copy of the original firmware.

Mistake 10: Selecting Based Solely on Price

Problem: The cheapest motor fails prematurely, has poor documentation, or causes machine downtime.

Solution: Consider TCO, support quality, and reliability track record. Buy from established vendors with global presence.

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Part 12: Future Trends and Closing Recommendations

The EtherCAT Integrated Motor market is evolving rapidly. When selecting today, consider these future trends to ensure your choice remains relevant for years.

12.1 Single‑Cable Solutions (Hybrid Cables)

Some newer integrated motors combine power and EtherCAT into a single hybrid cable (e.g., using a 4‑core power + 2 twisted pairs for data). This reduces cabling even further. However, be cautious: hybrid c