IONI specifications

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This page lists official functional, electrical and physical specifications of the IONI Servo Drive.

Device variations

IONI is available in three different models. See also IONI device model comparison.

Standard model
Advanced model, additional features and increased current range
Same features as IONI Pro, except higher current and voltage range

Main functionality

Function Description
Servo/stepping motor drive Closed loop control of various types of servo motors by sinusoidal field oriented control with dead-time distortion correction and high dynamic range torque control.
  • Synchronous AC & BLDC motors
    • Sinusoidal and trapezoidal commutated
    • SPM (Surface Permanent Magnet) and IPM (Internal Permanent Magnet) types
  • Brush DC motors
  • Linear motors
    • Iron core
    • Ironless (with external inductive filter)
  • Stepping motor, 2 phase (4,6 or 8 wires)
Control modes
  • Torque control
  • Velocity/speed control
  • Position control
Setpoint types

See setpoint signal / reference inputs list

Closed loop Cascaded control loops (PIV):
  • Torque / current control, update frequency 20.0 kHz
  • Velocity control, update frequency 2.5 kHz
  • Position control, update frequency 2.5 kHz
Feed-forwards Feed-forwards working in velocity & position control modes:
  • Acceleration (inertia canceling) feed-forward
  • Velocity (friction canceling) feed-forward
Homing Integrated homing function for position control mode:
  • Sensorless hard-stop homing
  • Home switch search
  • Index pulse search
  • Soft position limits (eliminate limit switches)
Feedback devices See feedback devices list
  • Safe torque off with 3-way redundancy
  • Charge pump enable input
  • Stopping motor on errors
    • Tracking error (velocity & position)
    • Over speed error
    • Limit switch
  • DC motor runaway prevention on feedback loss
  • Communication error detection
  • Over current
  • Short circuit (phase-to-phase)
  • I2t motor thermal protection
  • Over & under voltage
  • Over temperature
Power supply
  • Externally supplied
    • IONI, IONI Pro 5 – 52 VDC
    • IONI Pro HC 5 - 55 VDC
  • Additionally an external 5 VDC logic supply required. Note: if drive is used with IONICUBE motherboards, then 24 VDC logic supply voltage is needed instead as IONICUBE has on-board 5V regulator.
Motor output current1
  • AC/BLDC/Stepping/Linear motors (current specified as peak of sine):
    • IONI 0-15 A
    • IONI Pro 0-18 A
    • IONI Pro HC 0-25 A
  • Brush DC motors:
    • IONI 0-19.5 A
    • IONI Pro 0-23.4 A
    • IONI Pro HC 0-30 A
Compliance CE (LVD & EMC): EN IEC 62368-1:2018, IEC 61000-6-1:2005 and IEC 61000-6-3:2006.

SIL2: IEC 61800-5-2:2016-04


  • In order to meet EMC standard requirements, a proper installation and wiring is necessary. Refer to user guide for proper installation.
  • Signed Declaration of Conformity will be provided on request.
  • MTBF: 2.99 million hours
  • Failure rate (all delivered units, actual statistic from 2015-2017): 0.36%

1) Currents achievable continuously only with with sufficient coolant air flow. Without forced cooling, typically 30-45% of the maximum range can be driven continuously. Despite of this, maximum current is available for short periods of time even without cooling. Current is automatically throttled on temperature rise to protect the drive.


Property Value Units
Dimensions 70.5 × 37 × 7.5 (W×H×D) mm
Weight 14.0 ± 0.5 g
Drawings Download-icon.png 2D (PDF), Download-icon.png 3D (IGES & STEP)
Pinout IONI connector pinout


Property Value Units
Operating temperature -10...+75, non condensing °C
Storage temperature -30...+90, non condensing °C
Humidity 0-95 non-condensing  %
Power dissipation 0.3-15¹ W

¹) Power dissipation is output current and input voltage related.

Power supply

Supply2 Input voltage Input current typ Input current max
Logic power 5 VDC +/- 10%4 0.1 - 0.3 A 0.2 A
Motor power 5 - 52 VDC3 (IONI, IONI Pro), 5 - 55 VDC 3 (IONI Pro HC) 0 - 23.5 A1 23.5 A1

1) Estimating true current or power consumption based on this table may be difficult as current demand typically varies greatly and and almost completely depends on motor load conditions.

2) Both logic and motor supplies are required.

3) Possible to use from 5 VDC upwards, however short circuit protection feature is lost below 12 VDC.

4) IONICUBE motherboards provide on-board 5V regulator and accepts 24 VDC logic supply voltage. With IONICUBE no 5V supply is needed.

Motor output

Maximum output current throttling vs device temperature. Current is automatically reduced by device to protect from overheating.
Property Value Units Remarks
Supported motors AC, BLDC, DC, Linear Permanent magnet motors only
Continuous output current 0-151 (IONI), 0-181 (IONI Pro), 0-251 (IONI Pro HC) A (peak value of sine) User settable limit
Peak output current 0-151 (IONI), 0-181 (IONI Pro), 0-251 (IONI Pro HC) A (peak value of sine) User settable current limit.
Maximum effective motor phase output voltage
  • 3-phase AC motors: Vsupply*0.671 V RMS (phase-to-phase)
  • DC motors: Vsupply*0.95 VDC
  • I.e. at 48V supply, the maximum three-phase motor output voltage is 32.2 V RMS phase-to-phase
  • I.e. at 48V supply, the maximum DC motor output voltage is 45.6 V
Switching frequency 20.0 kHz
Maximum modulation depth 95  % Maximum effective output is 95% of HV DC bus voltage.
Torque control bandwidth (typ.) 1-3.3 kHz Motor coil dependent
Torque control cycle time 50.0 µs
Position & velocity control cycle time 400 µs
Power conversion efficiency 93-97  % Under typical conditions
Motor inductance range @ 48 VDC 0.2-25 mH
Motor inductance range @ 24 VDC 0.1-25 mH
Motor power range 0.01 - 0.5 kW
AC commutation frequency 0-400 Hz Not capped, may achieve up to 2 kHz

1) Maximum current is obtainable only for short periods without active air cooling. Drive automatically throttles current limit if drive temperature rises beyond 75 Celsius. Output current capacity reduces linearly between 75 and 90 degrees Celsius from the maximum to zero.

Regenerative resistor

IONI has a dedicated 3.3V logic level output for regenerative resistor control. The logic signal can be externally fed to a switch component (such as MOSFET) to drive external regenerative resistor to prevent overvoltage during rapid motor decelerations.

Feedback devices

Status of feedback device support

Feedback device type Status Electrical interface
Quadrature incremental encoder Standard feature Differential 3-5.5V (RS422), Single ended 3-5.5V (CMOS,TTL,open collector)
Hall sensors Standard feature Single ended 3-5.5V (CMOS,TTL,open collector). Differential signals accepted.
Analog SinCos encoder Standard feature in IONI Pro 1 V p-p signal, user selectable 16X, 64X or 256X resolution interpolation factor (note 1). Automatic signal gain and offset calibration.
Serial SSI absolute encoder Standard feature in IONI Pro, see more info RS422/RS485
Serial BiSS absolute encoder Standard feature in IONI Pro, see more info RS422/RS485

1) The final resolution will be 4*line_count*interpolation_factor. I.e. with 1000 lines/electrical cycles per revolution SinCos encoder, the supported resolutions are 64000, 256000 and 1024000 counts per revolution. SinCos encoder can be also used without interpolation (4*line_count resolution).

Quadrature & SinCos encoder electrical properties

Property Value Units Remarks
Encoder count rate
  • IONI: 0-4
  • IONI Pro: 0-18
MHz After 4x decoding, digitally filtered
SinCos encoder input frequency
  • IONI Pro: 0-1
MHz Max theoretical count rate at 256X interpolation becomes 1MHz*4*256 = 1024 MHz, however parameter Over speed faultFEV accepted value range might limit the achievable count rate to 75 MHz.
Supply voltage 4.8-5.2 V Supplied externally (can share same voltage with drive logic supply)

Setpoint signal / reference inputs

Setpoint signal type Status Electrical interface
Analog Standard feature
  • Up to +/-10V or any lower voltage range
  • +/-10V (bipolar) and 0-10V with polarity input (unipolar) supported
Pulse and direction Standard feature

Maximum step rate

  • IONI: 4 MHz
  • IONI Pro: 8 MHz
Quadrature Standard feature

Maximum quadrature frequency (count rate)

  • IONI: 1 MHz (4 MHz)
  • IONI Pro: 2 MHz (8 MHz)
PWM Standard feature
  • 1-30 kHz PWM carrier frequency (fPWM), ~3 kHz for optimal operation.
  • Single signal (no polarity input), zero setpoint at 50% duty
  • PWM signal is sampled at 60MHz timer thus reading resolution is 60MHz/fPWM
  • PWM+Polarity input mode
Serial communication Standard feature SimpleMotion V2 real-time serial bus with open source SDK. Connect through RS485 or USB.
EtherCAT Under development Realized with add-on board, EtherFOX

See also:

Inputs / outputs

List of I/O's

  • Setpoint inputs
    • Two digital channels (pulse/dir, quadrature or PWM)
    • One +/-10V analog channel (differential, 2 wires)
  • Digital inputs
    • Switch inputs (3 channels): home switch, positive travel limit switch, negative travel limit switch
    • Status control inputs (3 channels): enable, clear faults, STO
  • Feedback inputs
    • Quadrature encoder (3 channels differential, where 2 channels capable of 12 bit analog sampling)
    • Hall sensors (3 channels)
  • Digital outputs (3.3V logic level)
    • Regenerative brake control output (external power switch needed, such as MOSFET)
    • Holding brake control output (external power switch needed, such as MOSFET)
    • Status indication outputs (3 channels): fault stop, servo ready, tracking error warning
  • Serial comminication interfaces

Electrical characteristics

  • Digital inputs accept standard signal levels 2.7 - 5.5 VDC, except STO and Enable inputs accept 4 - 26 VDC.
  • Digital outputs provide 3.3 VDC signal level
  • Analog inputs accept +-/10 VDC (+/- 12 VDC max) referenced to GND

Detailed properties

For detailed pin specific description and electrical ratings, see IONI connector pinout.


Property Value Units
Communication protocol SimpleMotion V2
Default bitrate 460.8 kBPS
Supported high bit rates 1, 2, 3, 4, 4.5 MBPS
Maximum number of SMV2 devices chained in a single bus 32 pcs
Command throughput Up to 20000 Commands/s


Feature Properties Remarks
Safe torque off
  • One dedicated physical STO input
  1. Cut gate drive voltage rendering power stage inactive @ STO2 input
  2. Disable motor control @ STO2 input (software based)

Reaction time from STO2 signal voltage going below 2 volts to de-energized motor is maximum 5 ms.

Control error detection
  • Tracking error (velocity & position)
  • Over speed error
  • Limit switch
  • DC motor runaway prevention on feedback loss
  • Communication error
Electrical safety
  • ESD, short circuit, reverse polarity protection on all pins
Overload safety
  • Over current
  • Short circuit (phase-to-phase)
  • I2t motor thermal protection
  • Over & under voltage
  • Drive over temperature


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