Pluto is a high performance closed-loop servo drive controller suitable for DC brushed, voice coils, and brushless motors and supports trapezoidal and sinusoidal commutation.

The drive is available with EtherCAT and CANopen interfaces, enabling a wide choice of interfacing methods. From version 3.0 onwards, the CANopen is rugged and fully isolated. It can also be accessed from USB. Its extended voltage operating range up to 60 V allows its use in several applications, and the small footprint and the needless of an external heatsink allow the controller to be a valid OEM for critical-size applications.

The design also includes a wide variety of self-protection mechanisms making it a reliable option for your motor control application.

Pluto part numbering

Ordering part number	Status	Image
PLU-1/48-C	ON DEMAND
PLU-5/48-C	ACTIVE
PLU-8/48-C	ACTIVE
PLU-1/48-E	ON DEMAND
PLU-5/48-E	ACTIVE
PLU-8/48-E	ACTIVE

Legacy Part Numbers

Part numbers have changed from Pluto Manual version 4. Follow this equivalence to identify your old Pluto:

PLU-HS → PLU-1/48-y
PLU-STD → PLU-5/48-y
PLU-EXT → PLU-8/48-y

Specifications

Electrical and power specifications
Part number →	PLU-1/48-y	PLU-5/48-y	PLU-8/48-y
Nominal power supply voltage	10 V_DC to 48 V_{DC (Current ratings and nominal performance is given at this range.)}
Maximum continuous power supply voltage	59 V_DC (For revisions 2.1.1 onward), 53 V_DC (For 2.1.0 and previous revisions)
Transient peak power supply voltage	62.5 V @ 100 ms (For revisions 2.1.1 onward), 60 V @ 100 ms (For 2.1.0 and previous revisions)
Logic supply voltage	Not needed, supplied from Power supply voltage
Internal DC bus capacitance	112 µF
Minimum motor inductance	200 µH
Nominal phase continuous current	1 A_RMS	5 A_RMS	8 A_RMS
Maximum phase peak current	2 A_RMS (5 s)	10 A_RMS (5 s)	16 A_RMS (5 s)
Current sense range	± 4.8 A	± 19.2 A	± 32 A
Current sense resolution	9.35 mA/count	37.39 mA/count	62.32 mA/count
Shunt braking transistor	Shunt braking transistor on board. 16 A maximum current. Dimensioning a Shunt Resistor for Regenerative Braking
Cold plate	No
Power connectors	Pluggable terminal block 3.5 mm pitch
Standby power consumption	1.5 W (max). 2 W EtherCAT version (PLU-x/xx-E)
Efficiency	> 97% at the rated power and current
Motion control specifications
Motion control core	Ingenia 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	40 kHz (default) 20 kHz (alternative PWM frequency, configurable)
Current sensing	On phases A, B and C using 4 terminal kelvin shunt resistors. Accuracy is ± 1% full scale. 10 bit ADC resolution.
Sensors for commutation (brushless motors)	Digital halls (Trapezoidal) Analog halls (Sinusoidal / Trapezoidal) Quad. Incremental encoder differential and single-ended (Sinusoidal / Trapezoidal) PWM encoder (Sinusoidal / Trapezoidal) Analog potentiometer (Sinusoidal / Trapezoidal) Pluto does not allow Sin-Cos encoder. For a drive with similar form factor power and Sin-Cos encoder see the Nix Servo Drive.
Sensors supported for servo loops	Digital halls Analog halls Quadr. Incremental encoder PWM encoder Analog potentiometer DC tachometer
Supported target sources	Network communication – USB Network communication – CANopen Network communication – EtherCAT Standalone (execution from internal EEPROM memory) Analog input (±10 V or 0 V to 5 V) 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 Pulse, HS_GPI2 Direction (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. (24V 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 Overload (I²t) 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 (1500 W peak TVS diode).
Motor brake	Motor brake output through GPO1 or GPO2. Up to 24 V and 1 A.
Communications
USB	µUSB (2.0) connector.
CANopen	1.x.x and 2.x.x. versions: Non-isolated	CiA-301, CiA-305 and CiA-402 compliant. Maximum baud rate of 1 Mbps. Not isolated. 120 Ω termination not included on board.
CANopen	3.0 and next versions: Isolated	CiA-301, CiA-305 and CiA-402 compliant. Maximum baud rate of 1 Mbps. Robust bus fault tolerant up to ±65 V between CANH, CANL and CAN_GND_ISO. Galvanic insulation, Maximum 1500 V DC voltage. 120 Ω termination not included onboard.
EtherCAT	Available on PLU-x/yy-E versions.
Environmental and mechanical specifications
Ambient air temperature	-40 ºC to +50 ºC full current (operating) +50 ºC to +100 ºC current derating (operating) -40 to +125 ºC (storage)
Maximum humidity	5% - 85% (non-condensing)
Dimensions	60 mm x 60 mm x 15 mm
Weight (exc. mating connectors)	35 g

Hardware revisions

Hardware revision*	Description and changes
1.0.1R	First product release.
1.1.0R	CAN connector change from 4 ways to 3 ways (Phoenix Contact 1937509). PE pin is removed from connector. PE connection should be made with the plated mounting holes CAN LEDs position change Supply connector change from 4 ways to 3 ways (Phoenix Contact 1937509). PE pin is removed from connector. PE connection should be made with the plated mounting holes IO connector change TE Micro-Match model 8-188275-6. Same pinout except one change: +5.0 V output is added at pin 16. (Version 1.0.1 had this pin connected to GND) Feedback connector change to TE Micro-Match model 8-188275-2. Pinout remains identical to version 1.0.1R Increased USB port electrical robustness and noise immunity Readjusted power stage elements to minimize electromagnetic emissions
2.0.1R	Added EtherCAT connectivity PCB and PCA modifications to improve manufacturing reliability Changed rounded corners radius for aesthetic reasons High-speed (HS) digital inputs interface are pre-biased to allow easy wiring in single ended applications Added STO (Safe Torque Off) as a mounting option upon demand
2.1.0	Manufacturing improvements and component upgrades Improvements on power stage transistors to minimize losses in all versions Removed unnecessary components CAN connector changed to FCI 20020110-C031A01LF (green) to avoid confusion with the supply and shunt connector Silkscreen improvements
2.1.1	Upgraded maximum supply voltage to 59 V.
3.0	Added galvanic isolation to CAN interface to improve electrical safety and common mode noise immunity Protected CAN interface against accidental connection of power supply up to ±60 V to CANH and CANL Added logic supply through USB Reduced standby power consumption by 100 mW ~ 200 mW by changing linear regulators to high efficiency DC/DC Manufacturing improvements and component upgrades

Identifying the hardware revision

*Hardware revision is screen printed on the board.

Power and current ratings

Pluto is capable of providing the nominal current from -40ºC to 50ºC ambient air temperature without the need of any additional heatsink or forced cooling system powered at 48 V. From 50ºC to 80ºC of ambient temperature a current derating is needed.

Excessive power losses lead to over temperature that will be detected and cause the drive to turn off. The system temperature is available in E-Core registers and is measured on the power stage. The temperature parameter that can be accessed from USB 2.0 or CAN interface does not indicate the air temperature. Above 110ºC the Pluto 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 reset 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 Pluto exceed 100ºC when operating, especially at high load levels.
Do not touch the drive 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.

PlutoPowerDiagram

Current ratings

The Pluto Servo drive has no cold plate, so the board itself is the heatsink. 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 (T_P< 110ºC). The threshold temperature where the current derating should start depends on the DC bus voltage, available cooling and PWM frequency configuration.

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 Pluto 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:

T is the full cycle period.

I₁ is the current during t₁

I₂ is the current during t₂

I_n is the current during t_n

System temperature

Next thermal image shows an example of the heat distribution in a the PLU-8/48-y. The test has been performed at maximum load and air temperature in a 3 phase application.

To improve the power performance of the drive a heatsink can be added on top of the power stage transistors with a thick (>1 mm) thermal interface material gap pad. This will extend the performance of the drive. For further details ask Ingenia Support.

The drive is getting hot even at 0 current!

This is normal. Pluto 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 the motor is off, exit motor enable mode which will switch off the power stage.

Architecture

The following figure shows a simplified hardware architecture of the Pluto Servo Drive. Links provide direct access to relevant pages.

Pluto_HW_Architecture