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Leto BLDC Motor
OVU00243 Leto BLDC Motor Endstop
OVU00244 Leto BLDC Motor Continuous
Technical Manual Product Code: OVU00243/OVU00244
Rev 1
www.overview.co.uk
25 July 2016 This is the property of Overview Limited, no copying without
permission except as permitted by copyright law 2
Contents 1. Introduction .......................................................................................................................................... 3
2. Product Features .................................................................................................................................. 3
3. Precautions and Warnings ........................................................................................... 3
4. Product Specification ............................................................................................................................ 4
4.3. Motor Performance Data ............................................................................................................. 6
5. Product Makeup ................................................................................................................................... 7
5.1. Product Drawing Leto BLDC Motor Limited Rotation .................................................................. 7
5.2. Exploded View Limited Rotation Motor ....................................................................................... 8
6. Packaging Specification ........................................................................................................................ 9
7. Installation / Connection .................................................................................................................... 10
7.1. PCBA ........................................................................................................................................... 10
7.2. Mechanical ................................................................................................................................. 11
8. Software Set-up .................................................................................................................................. 12
8.1. I2C Interface ................................................................................................................................ 12
8.1.1. Physical Layer ..................................................................................................................... 12
8.1.2. Communications Layer ....................................................................................................... 12
8.1.3. Startup ................................................................................................................................ 12
8.2. I2C Control Commands................................................................................................................ 13
9. Compliance & Testing Specification ................................................................................................... 14
9.1. Product Testing Specification ..................................................................................................... 14
9.2. CE Compliance Specification ...................................................................................................... 15
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1. Introduction
The Leto BLDC direct drive motors have been designed to be integrated into a number of
environments that require a combination of high positional accuracy as well as smooth and silent
motion. These include video conferencing, broadcast and CCTV PTZ applications. The Leto platform
creates a standalone intelligent motor with integral low level motor control and integrated optical
feedback. It is robust to external dynamic disturbances, especially impulses and vibrations.
2. Product Features
Wide dynamic speed range from 0.05°s-1 to 720°s-1.
Rapid and precise positional control to 0.005° accuracy.
Near silent operation.
Integral DSP based motor controller.
High level control commands fed through a simple, 2-wire I²C bus.
PCBA connections conveniently arranged for use in a pan/tilt camera product.
All control and drive components are contained within the 56mm by 63mm PCB.
Configurations to provide continuous or limited rotation as necessary.
Hollow/non-magnetic shaft for slip ring integration.
User configurable gains and accelerations as well as the ability to in-field upgrade firmware.
3. Precautions and Warnings
Please study this technical manual thoroughly.
To prevent the risk of hazards such as fire or shock, do not expose this product to water.
Do not drop or shake the carton, avoid impacts and crash, take care when handling. The box cannot
give complete protection against heavy shocks.
Ensure appropriate ESD preventative actions are taken when handling this product.
Do not install the product in wet or high humidity areas without adequate protection. Moisture can
corrode the electrical components inside the product over time.
The product is guaranteed for use within temperatures of -20°C and +70°C and not suitable outside
those limits and for environments with extreme temperatures.
Do not disassemble the product, this will void the warranty.
This product is not suitable for the following environments:
Explosive atmospheres,
Life critical systems,
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4. Product Specification
All electronic components are of industrial grade, with temperature ratings of at least -20°C and +70°C.
4.1. Motor Electrical Data
This section includes the electrical parameters of the motor including motor data, design specifications,
test results and nominal values shown in Table 1 and Table 2.
Table 1 : Motor electrical data at 24V unless otherwise specified.
Performance Data Value
Operating Voltage 21.6V to 26.4V
Current at Max Torque) 540mA
Initialisation current 540mA
No Load Current 30mA
Max. Input Voltage Ripple 250mV@100kHz
Winding Resistance / Ph 15 Ω±10%
Winding Inductance /Ph 6.8mH (@ 1kHz)
Motor Constant 0.026 Nm/√w
Resolution (deg) 0.0055
Max Speed (deg/s) 720
Min Speed (deg/s) 0.05
Rotor Poles 16
Number of Phases 3
Stator Slots 12
Table 2 : Motor rated values at 24V unless otherwise specified.
Rated Values of the Motor Value
Rated Voltage 24V
Rated Current 500mA
Rated Temperature 25°C ± 10°C
Rated Load Moment of Inertia 16,570 gcm² Rated Speed 360°s¯¹
Torque at Rated Speed 79mNm
Rated Load MTBFa >1,000,000 hours
a Refer to product chassis camera loading conditions.
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4.2. Motor Mechanical Data
Table 3 : Motor environmental capabilities.
Specification Value
Temperature rated (standard operation) -20°C to +70°C
Humidity range (standard operation) 5% to 90% RH at 40°C
Storage Conditions -20°C to +70°C
Storage Humidity (% RH non-condensing) 5% - 85%
Table 4 : Motor mechanical power and mechanical properties.
Specification Value
Weight 102g
Rotor moment of Inertia 140gcm²
Locked Rotor/Stall /Holding Torque 91mNm
Cogging torque 4.1mNm max
Moving Torque 79mNm
Perpendicularity (deg) < +/-0.1
Maximum Radial load 65N
Maximum Axial load 65Nb
Range Configurable between 0°-360° including continuous rotation
b When either the axial or radial load is 0N, the other axis can be loaded more.
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4.3. Motor Performance Data
Figure 1 : 180 degree move profile with varying accelerations.
Figure 2 : 180 degree move profile with varying maximum speeds.
Figure 3 : Current vs torque curves of the Leto motor showing DC Input.
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5. Product Makeup
5.1. Product Drawing Leto BLDC Motor Limited Rotation
Figure 4 : Leto BLDC Motor Limited Rotation.
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5.2. Exploded View Limited Rotation Motor
Figure 5 : Leto BLDC Motor Limited Rotation including part names and materials.
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6. Packaging Specification
Motors are packaged, 100 motors per box, 20 motors per tray. Each motor is individually packaged in a
durable plastic bag, and placed within an antistatic foam tray. On top of the 5 foam trays is an antistatic
lid. The box dimensions are 260mm(d) x 400mm(w) x537mm(L).
Figure 6 : Foam partition and tray views from different planes.
Table 5 : Foam partition, tray and box details.
Figure 7 : Pictures of the box, foam partition and tray group of 5 placed top of each other in the box.
# Part Name Qty Specification
1 Cardboard Outer Box 1 Double thickness corrugated cardboard
2 Foam Partition 1 Anti-static foam
3 Foam Tray 5
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7. Installation / Connection
7.1. PCBA
Figure 10 and Figure 11 below highlight the position of the three sockets and one switch on the PCBA for
interfacing with external systems.
Figure 8 : PCBA rear view with J3 & J4 highlighted.
Figure 9 : PBCA front view with J2 & SW1 highlighted.
Table 6 : J4 Connector details.
J4 Molex - 0522710979
Pin Signal
1 Vin
2 I2C SDA
3 I2C SCL
4 GND
5 PASS THROUGH 1
6 PASS THROUGH 2
7 GND
8 PASS THROUGH 3
9 PASS THROUGH 4
Table 7 : J2 Connector details.
J2 Molex 0522710979
Pin Signal
1 GND
2 GND
3 NO CONNECTION
4 NO CONNECTION
5 I2C SCL
6 I2C SDA
7 NO CONNECTION
8 VIN
9 VIN
Table 8 : J3 Connector details.
J3 JST S8B-SM4A-TF (LF)(SN)
Pin Signal
1 Vin
2 I2C SDA
3 I2C SCL
4 PASS THROUGH 3
5 PASS THROUGH 4
6 PASS THROUGH 2
7 PASS THROUGH 1
8 GND
Table 9 : SW1 Switch details.
SW1- Switch
Position Signal
ON ADDRESS 0 LOW
1 (OFF) ADDRESS 0 HIGH
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7.2. Mechanical
The two mounting faces of the motor have four M2 threaded holes provided for mechanical interfacing
with the motor. Appropriate thread engagement calculations should be carried out to prevent stripping
of threads during installation.
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8. Software Set-up
8.1. I2C Interface
NB Full I2C specification available from www.overview.co.uk
8.1.1. Physical Layer
A standard, 3.3V, two wire, I2C interface is provided by the motor consisting of a clock, SCL, and data, SDA,
line. Both SDA and SCL need to be pulled up to 3.3V. When the bus is not busy both lines will be high. The
SCL signal is always generated by the master and the BLDC motor will always be a slave on the bus. SDA
can be controlled by either the master or the slave being communicated to.
8.1.2. Communications Layer
With two exceptions all transitions of SDA will occur when SCL is low. The exceptions are the start
condition and the stop condition. Start condition (STX): All messages must start with this transition. SDA
is set from high to low while SCL is high. Stop condition (ETX): All messages must end with this transition.
SDA is set from low to high while SCL is high. Messages are of variable length but are split into 1 byte
blocks, most significant bit first, after which an acknowledge bit (ACK /NACK) is required from the receiving
party. An ACK bit is low and a NACK bit high.
8.1.3. Startup
To allow the motor firmware to be upgraded remotely, the device can be run in In-Field Programming (IFP) mode. This mode
will be activated if the “HOLD LAUNCH" command (0xF0) is received in the first 500ms after power up.
Figure 10 shows an outline of timings of the startup procedure.
Figure 10 : Leto motor start-up procedure. Grey boxes indicate when the motor may not be guaranteed to respond to I2C
messages.
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8.2. I2C Control Commands Table 10 : Accessible I2C commands / Full details available from www.overview.co.uk
Commands Details
0x01 Reset
0x02 Calibration complete
0x03 Is motor moving
0x04 Return current location
0x05 Goto absolute location
0x06 Goto relative location
0x07 Travel at velocity
0x08 Set acceleration
0x09 Goto absolute location in set time
0x0A Goto relative location in set time
0x0B Get acceleration
0x0C Set tuning algorithm proportional gain
0x0D Get tuning algorithm proportional gain
0x0E Set tuning algorithm integral gain
0x0F Get tuning algorithm integral gain
0x10 Set tuning algorithm differential gain
0x11 Get tuning algorithm differential gain
0x12 Set first endstop distance from mechanical endstop
0x13 Set mechanical motor range
0x14 Start calibration
0x15-0x18 Factory use only
0x19 Set pan continuous
0x1A Get pan continuous
0x1B Get firmware version
0x1C Wake up
0x1D Set sleep on power up mode
0x1E-0x22 Factory use only
0x23 Save settings to flash
0x24 Reload factory defaults
0x25-0x2E Factory use only
0x2F Get sleep on power up mode
0x30 Is sleeping
0x31-0x3F Factory use only
0x40 Goto relative position 360
0x41 Goto relative position at speed
0x42 Goto absolute position at speed
0x45 Get serial full
0x4A Get first endstop distance
0x4B Get mechanical motor range
0x4E Set use hall sensor
0x4F Get use hall sensor
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9. Compliance & Testing Specification
9.1. Product Testing Specification
Test pass parameter: 100% rated performance achievable after the following tests
Mechanical Specific Test
Test Description Standard Guaranteed Performance
Result
Functional Life (360° Pan)
The product shall be able to continually operate for the duration of an accelerated life test equivalent to: - Typical 3-position tour = 48 seconds (6 travel + 10 dwell) - Warranty = 2 years = 63113852 seconds = 1314872 tours
None specified No functional/
mechanical deviations
Pass
Functional Life (180° Pan)
The product shall be able to continually operate for the duration of an accelerated life test equivalent to: - Typical 3-position tour = 48 seconds (6 travel + 10 dwell) - Warranty = 2 years = 63113852 seconds = 1314872 tours
None specified No functional/
mechanical deviations
Pass
Electronic Specific Test
Test Description Standard Guaranteed Performance
Result
Noise and Sound Tested under rated voltages under no load and loaded conditions.
ISO 3746 Sound power
level stays below 32dBA
Pass
Running / Locked rotor overload
test
Motors are tested with locked and unlocked rotors, at different temperatures and diff increasing load values.
BS EN 60950-1:2006+A23:2011 (Annex B)
Temperatures must not
exceed Class H insulator
Pass
Dynamic Testing
Test Description Standard Guaranteed Performance
Result
Shock / Vibration
Product tested to Class 4M4 in the following variations: 1. 3,5mm, 10m/s², 5-200Hz, 10 sweep cycles, 3 perpendicular axis, one going with gravity. 2. 150m/s², 6ms, 100 shocks/axis, 6 perpendicular axis. 3. Non-operational.
IEC 60721-4-4 (verification standards
within)
No functional/ mechanical deviations
Pass
Impact / bump test
The Product is placed on a horizontal wooden support, which is allowed to fall 50 times from a height of 5 cm onto a wooden table.
BS EN 60065-2002+
A12:2011
No visible damage
Pass
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Environmental Testing
Test Description Standard Guaranteed Performance
Result
Climatic-standard
Product can operate within the conditions described in 5 variations of time/temp/cycles:
Temperature: -40°C to +85°C Relative humidity: 10%RH to 95%RH Absolute humidity: 0,9g/m² to 36g/m²
ICE 60721-3-4 (verification standards
within)
No functional/ mechanical deviations
Pass
Climatic-start-up
Product can operate within the conditions described in 5 variations of time/temp/cycles:
Temperature: -40°C to +85°C Relative humidity: 10%RH to 95%RH Absolute humidity: 0,9g/m² to 36g/m²
ICE 60721-3-4 (verification standards
within)
No functional/ mechanical deviations
Pass
Climatic-storage
Product can operate within the conditions described in 4 variations of time/temp/cycles:
Temperature: -40°C to +85°C Relative humidity: 10%RH to 95%RH Absolute humidity: 0,1g/m² to 36g/m²
ICE 60721-3-4 (verification standards
within)
No functional/ mechanical deviations
Pass
Ingress Test Motor is tested with the shroud on and off,
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EMC Directive Testing
Test Description Standard Guaranteed Performance
Result
Emissions Radiated
disturbances
Measurements shall be made with a quasi-peak measuring receiver in the frequent range 30MHz to 1000MHz.
BS EN 55022: 2010 Class B
Measurement within
specification Pass
Immunity Electrostatic
Discharge
10 indirect then 10 direct discharges shall be applied at each test voltage to preselected parts of the product.
BS EN 50130-4:2011
(Verification standards
within)
No mechanical damage,
malfunction or change of
status
Pass
Immunity Various tests ensuring the product is sufficiently Immune to voltage dips & bursts, short interruptions, and energy surges.
BS EN 50130-4:2011
(Verification standards
within)
No mechanical damage,
malfunction or change of
status
Pass
Machinery Directive Testing / IT Safety Testing (see above – mechanical & dynamic testing)
Test Description Standard Guaranteed Performance
Result
Risk assessment
Risk assessment and intended use/misuse documentation prepared.
BS EN 12100: 2010
Reviewed for improvement
to product N/A
Other Regulatory/Directive Requirements
Directive/ Regulation
Description Directive/ Regulation #
Guaranteed Performance
Result
ROHS All components in an Overview product/sub-assembly meet the requirements of the ROHS Directive
2011/65/EU Full
compliancy Confirmed
REACH Material declarations are checked against the candidate list when published. Customers will be advised if a components status changes.
EC/1907/2006 SVHC (REACH
Annex XIV)
Full compliancy
Confirmed
UL All plastic parts HB classified or better according to UL94 Standard. (flame resistance). UL94
Full compliancy
Confirmed
