# Product Description

The Nix Digital Servo Drive is an ultra-compact solution providing top performance, advanced networking and built in safety, as well as a fully featured motion controller. The NIX can control multiple motor types and supports almost any feedback sensor including absolute serial encoders.

Its incredibly compact design includes multiple communication ports, enabling thus a wide choice of interfacing methods. Its extended voltage operating range allows its use in several applications, the small form factor, 100ºC operation temperature and conduction cooling plate makes it a valid OEM for critical-size applications.

The Nix Digital Servo Drive has been designed with efficiency in mind. It incorporates cutting-edge MOSFET technology as well as optimized control algorithms to provide the perfect trade-off between EMI and efficiency. Nix Digital

Nix Servo Drive is provided with several general purpose inputs and outputs designed for 5 V TTL logic but tolerant up to 24 V and fully rugged. By using these inputs and outputs it is possible to implement alarm signals, connect digital sensors, activate external devices (LEDs, actuators, solenoids, etc.). Some of the digital and analog inputs can also be used as command / target sources.

# Nix part numbering

Ordering part numberStatusImage
NIX-10/48-C-Q
ACTIVE

NIX-5/170-C-Q

ON DEMAND

NIX-10/48-C-C
ACTIVE

NIX-5/170-C-C
ACTIVE
NIX-10/48-E-C
ACTIVE

NIX-5/170-E-C
ACTIVE
NIX-10/48-C-P

ON DEMAND

NIX-5/170-C-P

ON DEMAND

# Specifications

Electrical and power specifications

Part number →NIX-10/48-x-xNIX-5/170-x-x

Nominal power supply voltage

10 VDC to 48 VDC (Current ratings and nominal performance is given at this range.)

10 VDC to 170 VDC (Current ratings and nominal performance is given at this range.)

Maximum continuous power supply voltage 53 VDC175 VDC
Transient peak voltage65 V @ 100 ms

200 V @ 100 ms

Logic supply voltage

10 VDC to 48 VDC

If logic supply is not connected, the board is powered from power supply with a bypass diode.

NIX-10/48 double supply

For double supplying the NIX-10/48, logic supply voltage must be
higher than or equal to power supply voltage
.

10 VDC to 48 VDC

Two different supplies are needed for this version.

Note that logic supply voltage < power supply voltage.

Do not connect them together at voltages > 48 V.

Logic supply power5 W (considering I/O and feedback supplies)
Internal DC bus capacitance88 µF13 µF
Minimum motor inductance200 µH

Nominal phase continuous current

10 ARMS

5 ARMS

Maximum phase peak current

20 ARMS (5 s)

10 ARMS (5 s)
Current sense range± 29 A± 19 A
Current sense resolution56.65 mA/count37.39 mA/count
Shunt braking transistor

Shunt braking transistor on board.

16 A maximum current. Product Description

Shunt braking transistor on board.

5 A maximum current.

Cold plateHigh heat transfer black anodized aluminum
Power connectors

Pluggable terminal block 3.5 mm pitch / Pin header 3.5 mm pitch

Standby power consumption

1.5 W (max)

Efficiency

>97% at the rated power and current

Motion control specifications

Motion control coreIngenia E-Core with EMCL2.

Supported motor types

• Rotary brushless (trapezoidal and sinusoidal)
• Linear brushless (trapezoidal and sinusoidal)
• DC brushed
• Rotary voice coil
• Linear voice coil

Power stage PWM frequency

20 kHz (default)

80 kHz (alternative PWM frequency, configurable)

The default value of the PWM frequency has changed from 40 kHz to 20 kHz to reduce electro-magnetic interferences (EMI).

Current sensing

On phases A, B and C using 4 terminal shunt resistors.

Accuracy is ± 1% full scale.

Sensors for commutation

(brushless motors)

• Digital Halls (Trapezoidal)
• Analog Halls (Sinusoidal / Trapezoidal)
• Quad. Incremental encoder (Sinusoidal / Trapezoidal)
• PWM encoder (Sinusoidal / Trapezoidal)
• Analog potentiometer (Sinusoidal / Trapezoidal)
• Sin-Cos encoder (Sinusoidal / Trapezoidal)
• Absolute encoder SSI (Sinusoidal / Trapezoidal)

It is recommended to install the SSI only firmware variant if absolute encoder SSI is used for commutation.

Sensors supported for servo loops
• Digital Halls
• Analog Halls
• PWM encoder
• Analog potentiometer
• Sin-Cos encoder
• Absolute encoder
• DC tachometer

Supported target sources

• Network communication – USB
• Network communication – CANopen
• Network communication – RS485/RS422
• Network communication – EtherCAT
• Standalone (execution from internal EEPROM memory)
• Step and Direction (Pulse and direction)
• PWM command
• Encoder follower / Electronic Gearing

Inputs/outputs and protections

Inputs and outputs
• 2 x non isolated single ended digital inputs. GPI1, GPI2 (5 V TTL logic, 24 V tolerant).
• 2 x non isolated high speed differential digital inputs. HS_GPI1, HS_GPI2 (5 V logic, 24 V tolerant).
• 1 x (±10 V) differential analog input (12 bits). AN_IN2. (24 V tolerant).
• 1 x 0 V... 5 V single ended analog input (12 bits). AN_IN1. (24 V tolerant).
• 2 x Open open drain digital outputs with a weak pull-up to 5 V. (24 V tolerant and 1 A short-circuit and over-current rugged).
• 1 x 5 V output supply for powering external circuitry (up to 200 mA).

Protections

• User configurable:
• Bus over-voltage
• Bus under-voltage
• Over-temperature
• Under-temperature
• Over-current
• Short-circuit protections:
• Phase-DC bus
• Phase-phase
• Phase-GND
• Mechanical limits for homing functions.
• Hall sequence/combination error.
• ESD protections in all inputs, outputs, feedbacks and communications.
• EMI protections (noise filters) in all inputs, outputs and feedbacks.
• Inverse polarity supply protection (bidirectional).
• High power transient voltage suppressor for short braking (600 W peak TVS diode).
• Encoder broken wire detector (for differential quadrature encoders only).
Motor brake

Motor brake output through GPO1 or GPO2. Up to 24 V and 1 A.

Communications

USBµUSB (2.0) connector. The board can be supplied from USB for configuration purposes but will not power the motor.
SerialRS485 full-duplex (compatible with RS422), non-isolated. 120 Ω termination on the RX line (v 1.1.0) and on the TX line (v 1.2.0).
CANopenAvailable. Non-isolated. Includes jumper to enable 120 Ω termination.
CiA-301, CiA-305 and CiA-402 compliant.
EtherCATAvailable.

Environmental and mechanical specifications

Ambient air temperature

• -40 ºC to +50 ºC full current (Operating). If the Nix is mounted on a heatsink plate the range can be extended up to 85ºC heatsink temperature.
• +50 ºC to +100 ºC current derating (operating)
• -40 ºC to +125 ºC (storage)

Maximum humidity

5% - 85% (non-condensing)

Dimensions

75 x 60 x 14 mm. See Dimensions and Assembly.

Weight (exc. mating connectors)

86 g

# Hardware revisions

Hardware revision*Description and changes

1.0.0

November 2015

First product demo.

1.1.0

January 2016

First product release. Changes from previous version:

• DC bus transient voltage suppressor changed to improve MOSFET protection against overvoltage
• Logic supply TVS placed before the polarity inversion protection diode to protect against potential negative surges
• EtherCAT board is powered from V_LOGIC instead of DC bus.
• Logo and silkscreen improvements.
• Signalling LEDs flipped to improve better visibility.
• CAN termination resistor jumper placed in right angle.
• Power supply and shunt connector changed to 4 position terminal, including LOGIC_SUP pin.
• Motor connector changed to 3 position terminal, eliminating PE pin.
• Modification on component footprints to improve manufacturing reliability.

1.2.0

January 2017

Changes from previous version:

• Logic supply TVS changed for better surge tolerance.
• Default PWM frequency has been changed to 20 kHz.
• Modification of MOSFET driver for minimizing EMI.
• NIX-5/170 power supply TVS changed for power losses reduction.
• Termination resistor added on TX line of RS485.
• Modification of connectors footprints to improve manufacturing reliability.
• Jumper for CAN port enabling is now provided with Nix.

Identifying the hardware revision

Hardware revision is screen printed on the board.

# Power and current ratings

Nix is capable of providing the nominal current from -25ºC to 50ºC ambient air temperature without the need of any additional heatsink or forced cooling system. From 50ºC to 100ºC of ambient temperature a current derating is needed. If the Nix is mounted on a heatsink plate the range before derating can be extended up to 85ºC.

Excessive power losses lead to over temperature that will be detected and cause a the drive to turn off. The system temperature is available in E-Core registers and is measured near the power stage. The temperature parameter that can be accessed from USB 2.0, CAN or RS485 serial interface does not indicate the air temperature. Above 105ºC the Nix automatically turns off the power stage and stay in fault state avoiding any damage to the drive. A Fault LED will be activated and cannot be reseted unless temperature decreases.

Drive safety is always ensured by its protections. However, power losses and temperature limit the allowable motor current.

Some parts of the Nix exceed 105ºC when operating, especially at high load levels.
Do not touch the Nix when operating and wait at least 5 minutes after turn off to allow a safe cool down.

Following figure shows the basic power flow and losses in a servo drive system.

## Power losses calculation (heat dissipation)

Operation of the Nix causes power losses that should be transferred to the surrounding environment as heat. Heat dissipation depends on various parameters. Principally:

• Motor RMS current: positive correlation.
• DC bus voltage: positive correlation.
• NIX product number: 170 V variant NIX-5/170 has different power transistors compared to the 48 V variants. The 170 V variant have greater power losses for a given motor current. Different charts are provided for each variant, see below.

Other less relevant parameters affect also the power loss but are not considered in the graphs:

• Air temperature, higher power semiconductor temperatures reduce their efficiency.
• Motor speed. Faster motor speeds result in higher overall power loss since the input current is greater. This increases conduction losses on the reverse polarity protection circuitry.

## Current ratings

Power losses cause the drive to increase its temperature according to:

$$T_P \approx T_A + P_{LOSS} · Z_{θ PA}$$

Power losses have a positive correlation with the motor RMS current. For this reason, when the ambient temperature rises, the output current must be limited to avoid an excessive drive temperature (TP< 110ºC). The threshold temperature where the current derating should start depends on the DC bus voltage and the Nix part number.

The thermal impedance typical value is shown above, however its exact value will vary according to:

• Air flow around the drive.
• Position (vertical allows natural convection).
ParameterValueUnitsNotes
Maximum power stage temperature110ºCMeasured on the power stage (not the heatsink) and accessible via register
Thermal resistance from power stage to air  3.8ºC/WWithout additional heatsink. Natural convection and radiation cooling.
Maximum power dissipation without heatsink16WAt TA 50ºC
Thermal resistance from power stage to heatsink1.58ºC/W
Thermal resistance between cold plate and heatsink not considered
Temperature stabilization time
600
s

Current derating

The current derating graph is only indicative and is based on thermal tests performed in a climatic room where there was enough room for natural air convection. Each application may reach different ratings depending on the installation, ventilation or housing. Current derating is only a recommendation and is not performed automatically by the drive.

## Dynamic application (non-constant current)

The Nix has a great thermal inertia that allows storing heat during short power pulses (exceeding nominal current) without overpassing the maximum temperature. This allows achieving high peak current ratings without need of additional heatsink.

For most systems where the cycle time is shorter than 3 τ (thermal time constant) the equivalent current can be calculated as the quadratic mean of the current during the full cycle. The load cycle can be simplified as different constant currents during some times:

$$I_{eq} = \sqrt{ \frac{t_1·I_1^2+t_2·I_2^2+ \cdots +t_n·I_n^2}{t_1+t_2+ \cdots +t_n}}$$

$$T = t_1+t_2+ \cdots +t_n$$

Where:

is the full cycle period.

I1 is the current during t1

I2 is the current during t

In is the current during tn

## System temperature

Next thermal image shows an example of the heat distribution in a NIX-10/48-y-z. This test has been performed without cold plate at maximum load and air temperature in a 3 phase application.

The drive is getting hot even at 0 current!

This is normal. Nix power stage includes high power MOSFET transistors which have parasitic capacitances. Switching them fast means charging and discharging those capacitors thousands of times per second which results in power losses and temperature increase even at 0 current!

Recommendation: when motor is off, exit motor enable mode which will switch off the power stage.

## Improving heat dissipation with a heatsink

A heatsink may be needed to extend the current range at high temperatures. When using high efficiency heatsinks or in enclosed spaces the equation can be simplified as follows.

$$T_P \approx T_A + P_{LOSS} · (Z_{θ PC} + Z_{θ CH} +Z_{θ HA})$$

Assembly recommendations for best heat dissipation

• Always allow natural air convection by ensuring ≥ 10 mm air space around the drive.
• Place the Nix in vertical position.
• Use a good thermal interface material to improve the heat dissipation when using heatsink. See Product Description for details.
• If housed, use a good thermal conductivity material such as black anodized aluminum. Placing the drive in a small plastic package will definitively reduce its temperature range.
• Temperature range can be increased by providing forced cooling with a fan or by placing a thermal gap pad on top of the board. Always ensure electrical isolation between live parts and the heatsink.

# Architecture

Following figure shows a simplified hardware architecture of the Nix. Links provide direct access to relevant pages.