DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com DMU10-01/-21 DMU10-02/-22 OEM Module Features 1 General Description • High performance six degrees of freedom (6-DOF) MEMS IMU • 7 sensor inputs - Angular rate (x3) - Linear acceleration (x3) - Temperature • Dynamic Range ±300°/s and ±10g • Bias instability <10°/hr and 0.05mg • Random Walk <0.4°/hr and 0.05m/s • Small (45 x 26 x 16mm) • User programmable bandwidth • 3.2 to 5.25V Supply • Wide operating temperature range -40°C to +85°C • RS-422 Interface • Optional Configurations: - Uncalibrated and thermally calibrated - OEM and Module • RoHS compliant DMU10 is a 6-DOF Precision MEMS Inertial Measurement Unit from Silicon Sensing Systems. It provides three axes of angular rate and linear acceleration, and temperature. The output message includes message counter, built-in test results, delta theta and delta velocity information. Data is output on an industry standard RS422 interface for ease of integration. DMU10 is engineered using Silicon Sensing’s own unique MEMS VSG5 ring gyroscope and capacitive accelerometer technologies to provide benchmark performance, size and affordability. It contains three 5th generation piezoelectric (PZT) gyroscopes and six accelerometers. Outputs from dual accelerometers per axis are averaged to improve precision and reduce uncorrelated noise. Available uncalibrated or calibrated over the full operating temperature range. DMU10 is supplied either as an OEM or a Module. Full Evaluation Kit available (see Section 8 for details). Applications • • • • • • • Machine control Antenna and Platform Stabilisation Precision Agriculture Autonomous Vehicles and ROVs Attitude Measurement Systems Personal Navigation GPS Aiding © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 1 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit PL1_2 www.siliconsensing.com 3.2 to 5.25V EXPANSION PORT 3.1V 3.1V 3.1V 3.1V REGULATOR PL1_1 GND 3.1V PL1_3 PL1_4 PL1_9 PL1_10 COMBI SENSOR 1 TEMPERATURE SENSOR RX_Lo 3.1V 3.1V RX RX_Hi RS422 I/F TX_Lo TX TX_Hi SPI I/F COMBI SENSOR 2 TX_TRISTATE RS422_TERMINATION PL1_12 PL1_11 PL1_6 PL1_7 PL1_8 PL1_5 MICROCONTROLLER FACTORY USE 3.1V SPARE RUN MODE COMBI SENSOR 3 AUX SYNC RESET C.G. 18710 26 22 Figure 1.1 DMU10 Functional Block Diagram DMU10 PT. NO. DMU10-02-0100 SER NO. WWYYXXXX C MADE IN PLYMOUTH UK 16 11 45 41 All dimensions in millimetres. Figure 1.2 DMU10 (OEM) Unit Overall Dimensions All dimensions in millimetres. Figure 1.3 DMU10 (Module) Unit Overall Dimensions © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 2 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 2 Ordering Information Calibration: UN = Uncalibrated, OT = Over Temperature Calibration Item Description Overall Dimensions Calibration Part Number UN DMU10-01-0100 OT DMU10-21-0100 UN DMU10-02-0100 OT DMU10-22-0100 OT DMU10-21-0500 mm Bare PCB with four mounting holes 41 x 22 x 10.6 DMU10 OEM Unit A two-part, anodised aluminium, non-hermetic housing. Three mounting lugs. 45 x 26 x 16 DMU10 Module Unit Customer evaluation kit comprising a DMU10-21-0100, RS422 to USB Connector, USB Driver and Data Logging Software, Cables and Connectors, Instruction Manual. Not Applicable DMU10 OEM Evaluation Kit © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 3 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 3 Performance Calibration: UN = Uncalibrated, OT = Over Temperature Calibration Parameter CAL Minimum Typical Maximum Notes All < -300 – > +300 Clamped at ±305°/s during over-range UN -3.00 ±1.50 +3.00 – OT -0.25 ±0.10 +0.25 – UN -0.125 ±0.05 +0.125 – OT -0.067 ±0.033 +0.067 – UN -3.30 ±1.65 +3.30 OT -0.50 ±0.25 +0.50 UN -0.20 ±0.10 +0.20 OT -0.05 ±0.025 +0.05 Bias Instability (°/hr) All – < 15.00 – Angle Random Walk ( °/hr) All – < 0.40 – UN -3600 ±1800 +3600 OT -300 ±150 +300 UN -6.00 ±2.00 +6.00 OT -0.7 ±0.35 +0.7 Gyro Bandwidth (Hz) All < 10 85 > 150 -3dB point User programmable Noise (°/s rms) All – 0.10 0.15 Wide band noise at 100Hz bandwidth VRE (°/s rms / g) All -0.006 ±0.003 +0.006 3.3g rms stimulus 20Hz to 2,000Hz Angular Rate (Roll, Pitch, Yaw) Dynamic Range (°/s) Scale Factor Error (%) Scale Factor Non-Linearity Error (%) Bias (°/s) Bias drift with time (°/s) Bias Repeatability (°/hr) Gyro Cross Coupling (%) Over operating temperature range At constant temperature As measured using the Allan Variance method. Bias Repeatability = √(Biaswarmup)2 + (Biastoto)2 + (Biasageing)2 + (Biastemperature)2 Over operating temperature range © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 4 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 3 Performance Continued Parameter CAL Minimum Typical Maximum Notes All < -10 – > +10 Clamped at ±10.01g during over-range UN -3.00 ±1.00 +3.00 – OT -0.25 ±0.10 +0.25 – UN -1.00 ±0.50 +1.00 OT -1.00 ±0.50 +1.00 UN -150.00 ±50.00 +150.00 OT -10.00 ±2.50 +10.00 UN -20.00 ±10.00 +20.00 OT -2.00 ±1.00 +2.00 Bias Instability (mg) All – < 0.05 – Random Walk (m/s/hr) All – < 0.05 – UN -30 ±15 +30 OT -2 ±1 +2 UN -6.00 ±3.00 +6.00 OT -0.70 ±0.35 +0.70 Acc Bandwidth (Hz) All < 10 90 > 150 -3dB point User programmable Noise (mg rms) All – 1.00 1.50 Wide band noise at 100Hz bandwidth Range (°C) All < -45 – > 100 Exceeds operational temperature range Accuracy (°C) All – ±3 – In the operational temperature range Linear Acceleration (X, Y, Z) Dynamic Range (g) Scale Factor Error (%) Scale Factor Non-Linearity Error (%) Bias (mg) Bias drift with time (mg) Bias Repeatability (mg) Acc Cross Coupling (%) Maximum error from best straight line over ±8g Over operating temperature range At constant temperature As measured using the Allan Variance method. Bias Repeatability = √(Biaswarmup)2 + (Biastoto)2 + (Biasageing)2 + (Biastemperature)2 Over operating temperature range Temperature Output © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 5 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 4 Environment, Power and Physical Parameter Minimum Typical Maximum Notes Operating Temperature Range (°C) -40 – +85 Full specification Storage Temperature Range (°C) -55 – +100 – Operational Shock (g) – – 95 6ms, half sinewave Non-Operational Shock (g) – – 500 0.1ms, half sinewave Operational Random Vibration (g rms) – – 3.3 20Hz to 2KHz Non-Operational Random Vibration (g rms) – – 10 20Hz to 2KHz Humidity (% rh) – – 85 Non-condensing Communication Protocol (Standard) – RS-422 – Full duplex communication Data Rate (Hz) – 200 (Default) – User programmable * future feature Baud Rate (BPS) – 460, 800 (Default) – User programmable * future feature Startup Time (s) – < 0.5 – – Current (mA) – 85 95 With 120 RS422 termination resistor +3.2 +5 +5.25 – Size (mm) – 41 x 22 x 10.6 – – Mass (grams) – 6 – – Size (mm) – 45 x 26 x 16 – – Mass (grams) – 24 – – Environment Interface Voltage (V) Physical (OEM) Physical (Module) © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 6 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 5 Typical Performance Characteristics This section shows the typical performance of DMU10 (Uncalibrated and Calibrated). 5.1 Performance Characteristics (Uncalibrated - DMU10-01 and DMU10-02) Figure 5.1 Gyroscope Bias Figure 5.2 Gyroscope Scale Factor Error Figure 5.3 Gyroscope Cross Coupling Figure 5.4 Gyroscope Non-Linearity Distribution © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 7 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com Typical Performance Characteristics (Uncalibrated - DMU10-01 and DMU10-02) Figure 5.5 Accelerometer Bias Figure 5.6 Accelerometer Scale Factor Error Figure 5.7 Accelerometer Cross Coupling Figure 5.8 Accelerometer Non-Linearity Error © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 8 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 5.2 Typical Performance Characteristics (Calibrated - DMU10-21 and DMU10-22) Figure 5.9 Gyroscope Bias Figure 5.10 Gyroscope Scale Factor Error Figure 5.11 Gyroscope Cross Coupling Figure 5.12 Gyroscope Non-Linearity Distribution © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 9 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com Typical Performance Characteristics (Calibrated - DMU10-21 and DMU10-22) Figure 5.13 Accelerometer Bias Figure 5.14 Accelerometer Scale Factor Error Figure 5.15 Accelerometer Cross Coupling Figure 5.16 Accelerometer Non-Linearity Error © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 10 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 5.3 Typical Performance Characteristics (Uncalibrated and Calibrated) Figure 5.17 Gyroscope Allan Variance Figure 5.18 Gyroscope Stability Figure 5.19 Gyroscope Cumulative Noise Figure 5.20 Gyroscope Spectral Noise © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 11 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com Typical Performance Characteristics (Uncalibrated and Calibrated) Figure 5.21 Gyroscope Noise over Temperature Figure 5.22 Accelerometer Allan Variance Figure 5.23 Accelerometer Stability Figure 5.24 Accelerometer Cumulative Noise © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 12 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com Typical Performance Characteristics (Uncalibrated and Calibrated) Figure 5.25 Accelerometer Spectral Noise Figure 5.26 Accelerometer Noise over Temperature © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 13 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit 6 Glossary of Terms www.siliconsensing.com 7 Interface Physical and electrical inter-connect and RS422 message information ADC Analogue to Digital Converter ARW Angle Random Walk AWG American Wire Gauge BPS Bits Per Second (or Baud Rate) BW Bandwidth C Celsius or Centigrade DAC Digital to Analogue Converter Rx Lo* DPH Degrees Per Hour Rx Hi* DPS Degrees Per Second Tx Lo DRIE Deep Reactive Ion Etch EMC Electro-Magnetic Compatibility ESD Electro-Static Damage F Farads h Hour HBM Human Body Model Hz Hertz, Cycles Per Second K Kilo MDS Material Datasheet MEMS Micro-Electro Mechanical Systems mV Milli-Volts NEC Not Electrically Connected NL Scale Factor Non-Linearity OEM Original Equipment Manufacturer OT Over Temperature PD Primary Drive PP Primary Pick-Off RC Resistor and Capacitor filter RT Room Temperature s Seconds SF Scale Factor SMT Surface Mount Technology SOG Silicon On Glass SD Secondary Drive SP Secondary Pick-Off T.B.A. To Be Advised T.B.D. To Be Determined V Volts 7.1 Electrical Interface 3.2 to 5.25V PL1_2 SYSTEM HOST (5V or 3.3V SYSTEM) PL1_3 PL1_4 PL1_9 Tx Hi PL1_10 RESET* DMU10 PL1_5 RUN MODE* PL1_6 SYNC* PL1_8 0V PL1_1 * These connections are optional and can be left not connected. C.G. 18711 Figure 7.1 Required Connections for RS422 Communications with DMU10 7.2 Physical Interface 10.05 2 12 1 11 4.90 Part No: HARWIN G125-MV11205L1 C.G. 18720 Figure 7.2 Male Connector DMU10 © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 14 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 7.3 Connector Specification 7.5 Communications with DMU10 The physical connector for the DMU10 is from the ‘Gecko’ family of connectors, produced by Harwin. The Run Mode pin on the connector is used to control the output from the DMU10. The “Free Run” or “Enabled” mode is active when the Pin is floating (not connected), and the output will be enabled. The part number for the board connector is G125-MV11205L1. The female mating connector used to interface with this connector is part number G125-204 12 96 L0 (with crimps G125-0010003 for 26 AWG wires or G125-0010005 for 28 AWG wires). 7.4 Pin Information Pin Label Signal In/Out 1 GND Ground connected of the DMU10 I +5V Input voltage to the DMU10. Can be between 3.2V and 5.25V I 3 Rx Lo The negative receive connection required for the RS422 communication I 4 Rx Hi The positive receive connection required for the RS422 communication I 5 Reset Microprocessor reset. Pin is pulled low to reset the device. Suggested implementation using TTL logic I Run Mode Device Enable/Disable. Pin is pulled high or not connected to enable the device. Pin is pulled low to disable the device. Suggested implementation using TTL logic 7 Aux Analogue input channel which integrates a signal into the output message of the DMU10. This functionality can be used to allow the user to synchronise with a known input clock I 8 Sync Output signal that can be used by an external system to synchronise with DMU10 O 9 Tx Lo The negative transmit connection required for the RS422 communication O 10 TX Hi The positive transmit connection required for the RS422 Communication O 11 Spare Not electrically connected N/A Factory Use Used by SSSL for programming purposes and should not be interfaced with N/A 2 6 12 Table 7.1 Pin Information The DMU10 output is disabled when the “Run Mode” Pin is pulled low. 7.6 Operational Message Output The Output Message is output on a RS422 Serial output at 460,800 baud using a non-return to zero protocol. Each byte contains a start bit (logic 0), 8 data bits and 2 stop bits (logic 1). Data is output in big endian format by default. Data is output at a rate of 200 messages per second. Each message contains 34 words (68 bytes) as described in Table 7.2. The message is transmitted if the “Run Mode” Pin is High (NC). If the “Run Mode” Pin changes to a Low (Disable output), while the message is being transmitted, the message is completed before the output is disabled. 7.7 Sensor Sampling and Synchronisation I The Inertial Sensors within DMU10 are all sampled at 1,000Hz. The ‘Sync Pulse’ on the connector is set HIGH at the start of the sampling and returned to LOW when the last Inertial Sensor is sampled. Pulses are therefore seen on the connector at 1,000Hz. The Inertial Sensor measurements are then filtered with a 2nd order low pass filter, also running at 1000Hz. The factory default setting for this filter has a corner frequency of > 85Hz. The internal sequence for DMU10 is: • Cycle 1: Sample Sensors, 2nd order Filter • Cycle 2: Sample Sensors, 2nd order Filter, Calculate Sensor Compensation • Cycle 3: Sample Sensors, 2nd order Filter, Apply Sensor Compensation • Cycle 4: Sample Sensors, 2nd order Filter, Calculate Delta Theta and Vels • Cycle 5: Sample Sensors, 2nd order Filter, Transmit Message The message is transmitted after the ‘Sync Pulse’ associated with Cycle 5 has returned LOW. The inertial data included in the message is generated when the ‘Sync Pulse’ associated with Cycle 3 was HIGH. This enables the external equipment to synchronise with the time when the Inertial Data was valid. © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 15 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 1ms SYNC Output Sensor logging 0.19ms Sensor logging filtering and temperature averaging 0.44ms 0.31ms Gyro and acceleration data logging Sensor Logging Temperature Voltage & BIT data logging Application of 2nd order filter (100Hz default) Gyro and acceleration data logging Temperature running average Temperature Voltage & BIT data logging Application of 2nd order filter (100Hz default) Temperature running average C.G. 18738 Figure 7.3 Relationship between SYNC and Sensor Logging Serial TX of 34 words at 460,800 baud: 1.623ms every 5ms (using DMA) TX End Sensor error calculation: 0.05ms every 5ms Sensor compensation: 0.03ms every 5ms TX Start DMA TX (continued from SLOT 4) DMA TX (continued from SLOT 0) Message processing 0.16ms 0.44ms SLOT 0 SLOT 1 SLOT 2 SLOT 3 SLOT 4 1,000Hz (1ms) 200Hz (5ms) Sensor logging filtering and temperature averaging C.G. 18739 Figure 7.4 Relationship between Sensor Logging, Compensation and Transmitted Output © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 16 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 7.8 Operational Message Definitions 7.9 System BIT Flags The data output message has the content and sequence as shown in the table below: 7.9.1 System Startup BIT Flags Item Word Data Item Value / Unit 0 0 Header 16 Bit, 0x55AA 1 1 Message Count 16 Bit, 0 to 65535 decimal 2 2-3 Axis X Rate 32 Bit Single Precision FP, (˚/s) 3 4-5 Axis X Acceleration 32 Bit Single Precision FP, (g) 4 6-7 Axis Y Rate 32 Bit Single Precision FP, (˚/s) 5 8-9 Axis Y Acceleration 32 Bit Single Precision FP, (g) 6 10-11 Axis Z Rate 32 Bit Single Precision FP, (˚/s) 7 12-13 Axis Z Acceleration 32 Bit Single Precision FP, (g) 8 14-15 Aux Input Voltage 32 Bit Single Precision FP, (volts) 9 16-17 Average IMU Temperature 32 Bit Single Precision FP, (˚C) 10 18-19 Axis X Delta Theta 32 Bit Single Precision FP, (˚) 11 20-21 Axis X Delta Vel 32 Bit Single Precision FP, (m/s) 12 22-23 Axis Y Delta Theta 32 Bit Single Precision FP, (˚) 13 24-25 Axis Y Delta Vel 32 Bit Single Precision FP, (m/s) 26-27 Axis Z Delta Theta 32 Bit Single Precision FP, (˚) 15 28-29 Aux Z Delta Vel 32 Bit Single Precision FP, (m/s) 16 30 System Startup BIT Flags 16 Bit decimal value System Operation BIT Flags 16 Bit decimal value 14 17 18 19 31 32 33 Error Operation BIT Flags 16 Bit decimal value Checksum 16 Bit 2’s Complement of the 16 Bit Sum of the Previous 0-18 data items These flags indicate errors detected during DMU10 Initialisation. Once set, these flags will not be cleared for the whole of the power cycle. BIT No. System Startup BIT Flags D00 Code_Checksum_Fail Set if the DMU10 code checksum does not match. If this flag is set, correct operation of the DMU10 cannot be guaranteed. D01 NVM_Coefficient_Checksum_Fail Set if the DMU10 NVM coefficient checksum does not match. If this flag is set, correct operation of the DMU10 cannot be guaranteed. D02 Orion_Startup_Error This flag will be set if there were any Orion Startup Flags set in any of the three 32 BIT Orion BIT flag arrays. The output items affected by this failure will be marked in the Item Error Indication table. D03 Internal_Processor_Error Set if there was an error accessing hardware internal to the microprocessor. D04 Invalid_NVM_Coefficient Set if an NVM coefficient value is invalid. If this affects an operational output item, the corresponding item will be marked in the Item Error Indication table and this should help to identify which coefficient is invalid. D05 Spare D06 Spare D07 Spare D08 Spare D09 Spare D010 Spare D011 Spare D012 Spare D013 Spare D014 Spare D015 Spare Table 7.3 System Startup BIT Flags Table 7.2 Operational Message Data Output Definitions © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 17 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit 7.9.2 System Operation BIT Flags These flags indicate errors detected during DMU10 operation. These flags are set per DMU10 output message and so may not appear in every returned message (because the fault may clear or be intermittent). BIT No. www.siliconsensing.com BIT No. System Operation BIT Flags D011 Spare D012 Spare D013 Spare D014 Spare D015 Spare System Operation BIT Flags D00 Voltage_Regulator_Range_Error Regulator Voltage BIT Function. D01 Scheduler_Slot_Period_Extended This flag will be set if the DMU10 software scheduler could not complete its allocated tasks within the required slot time. If this happens, the DMU10 will widen it’s scheduler slot time. This will normally be caused by a hardware fault that caused a timeout. When this flag is set, the DMU10 will output data at a decreased rate. Table 7.4 System Operation BIT Flags 7.9.3 System Error Indication BIT Flags These flags indicate which message items have faults associated with them. BIT No. System Error Indication BIT Flags Output_Message_Missed This flag will be set if the previous output message was missed. This will occur if the DMU10 was unable to output a serial port message because the previous message was still being sent. This will normally be caused by incompatible Message or Baud Rate selection. D00 Message Item 01 Error (X axis Rate for standard message format). D01 Message Item 02 Error (X axis acceleration for standard message format). D02 Message Item 03 Error (Y axis Rate for standard message format). D03 Message Item 04 Error (Y axis acceleration for standard message format). D03 Internal_Processor_Error This flag will be set if the software timed out while accessing hardware internal to the microprocessor (A/D, SPI). The output items affected by this failure will be marked in the Item Error Indication table. D04 Message Item 05 Error (Z axis Rate for standard message format). D05 Message Item 06 Error (Auxillary input for standard message format). D04 Orion_Operation_Error This flag will be set if there are any Orion Operation Flags set in any of the three 32 BIT Orion BIT flag arrays. The output items affected by this failure will be marked in the Error Indication table. D06 Message Item 07 Error (Temperature for standard message format). D07 Message Item 08 Error (X delta theta for standard message format). D08 Message Item 09 Error (X delta velocity for standard message format). D09 Message Item 10 Error (Y delta theta for standard message format). D010 Message Item 11 Error (Y delta velocity for standard message format). D011 Message Item 12 Error (Z delta theta for standard message format). D012 This currently only applies to accelerometer sensors which have corresponding sensors in the same sense axis. Message Item 13 Error (Z delta velocity for standard message format). D013 Message Item 14 Error. D02 D05 D06 Output_Value_Out_Of_Range Set when an output value has been clamped because it is out of range. The output items affected by this failure will be marked in the Error Indication table. Max Rate = ± 305˚/s Max Acceleration = ± 10.01g Plausibility_Error Set when the system has determined that a sampled sensor value is implausible. The output items affected by this failure will be marked in the Error Indication table. D07 Spare D014 Message Item 15 Error. D08 Spare D015 Message Item 16 Error. D09 Spare D010 Spare Table 7.5 System Error Indication BIT Flags © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 18 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 8 Design Tools and Resources Available Item Description of Resource Part Number Order/Download DMU10 Brochure: A one page sales brochure describing the key features of the DMU10 Inertial Measurement Unit. DMU10-00-0100-131 Download (www.siliconsensing.com) DMU10 Datasheet: Full technical information on all DMU10 Dynamic Measurement Unit part number options. Specification and other essential information for assembling and interfacing to DMU10 Inertial Measurement Unit, and getting the most out of it. DMU10-00-0100-132 Download (www.siliconsensing.com) DMU10 Evaluation Kit: DMU10 delivered with an RS422 to USB interface, plug-and-play real time display and logging software and two interface cabling solutions DMU10-21-0100 unit included. DMU10-21-0500 Order (www.siliconsensing.com) DMU10 Presentation: A useful presentation describing the features, construction, principles of operation and applications for the DMU10 Inertial Measurement Unit. — Download (www.siliconsensing.com) DMU10-01-0100-408 Solid Model CAD files for DMU10 Inertial Measurement Unit: Available in .STP and .IGS file format. Download (www.siliconsensing.com) DMU10-02-0100-408 Interface: Off-the-peg pseudo code and a simple flowchart with message handling instructions for use as a customer aid to developing their own interface directly to a DMU10 Inertial Measurement Unit via the RS422 interface. — Download (www.siliconsensing.com) Questions and Answers: Some useful questions asked by customers and how we’ve answered them. This is an informal (uncontrolled) document intended purely as additional information. — Download (www.siliconsensing.com) RoHS compliance statement for DMU10 : DMU10 is fully compliant with RoHS. For details of the materials used in the manufacture please refer to the MDS Report. — Download (www.siliconsensing.com) © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 19 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 8.1 DMU10 Evaluation Kit 9 Part Markings The DMU10 Evaluation Kit enables the output data from the DMU10 to be viewed and logged for testing and evaluation purposes. DMU10 is supplied with an adhesive label attached. The label displays readable DMU10 part and part identification numbers. The part identification number is a numeric code; WWYYXXXX C or CC where: WW = Manufacturing week number YY = Manufacturing year number XXXX = Serial number C/CC = Revision A 4x4 data matrix barcode containing the part identification number is also displayed on the label. Figure 8.1 DMU10 Evaluation Kit 8.1.1 DMU10 Evaluation Kit Contents The DMU10 Evaluation Kit (part number DMU10-21-0500) contains the following: DMU10 IMU (part number DMU10-21-0100). • MEV RS485i to USB converter. • CD containing the MEV drivers. • USB memory stick containing the data logging software. • Interface cables. • User manual. 8.1.2 System Requirements The DMU10 Evaluation Kit requires a PC with a USB port. The requirements for the PC are as follows: • Microsoft® Windows® XP (SP3 or greater), Vista®, Windows 7 or Windows 8 Operating Systems. The software has not been tested on any other Operating System and therefore correct functionality cannot be guaranteed. • Minimum of 500Mb of RAM. • 500Mb of free hard drive space plus space for logged data (typical data rate ≈ 50kbit/s). • High power or self-powered USB 2.0 Port. © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 20 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 10 Installation Details Figures 10.1 and 10.2 show the installation drawing for the DMU10, the OEM and Module versions respectively. The DMU10 (OEM) is supplied as a PCBA. It is recommended that the PCBA is mounted on spacers or pillars using the four mounting holes provided. The holes are clearance holes for use with M2.0 screws. During calibration, alignment is achieved using external reference dowels on two sides of the PCBA. These two sides therefore form the datum for alignment purposes. The DMU10 (Module) is designed for 3 point mounting using M2.5 screws. During calibration alignment is achieved using two external reference dowel holes on the base of the DMU10. The dowel holes are designed to be used with two Ø2mm (in accordance with BS EN ISO 8734 or BS EN ISO 2338) dowel pins provided by the host. The DMU10 mounting screw torque settings will be dependent on the host application; it will for example vary depending on the specification of the screw, the material of the host structure and whether a locking compound is used. When securing a DMU10 OEM unit to the host system using steel M2 screws and a thread locking compound the suggested torque setting is 0.1Nm for securing to an aluminium host structure. When securing a DMU10 Module unit to the host system using steel M2.5 screws and a thread locking compound the suggested torque setting is 0.2Nm for securing to an aluminium host structure. This information is provided for guidance purposes only, the actual torque settings are the responsibility of the host system designer. Alignment Dowels used for Calibration and Test 3x Ø 3.199 3.188 5.2 22 17.4 6 25.6 28.4 1.6 7 2 4x Ø 2.4 2.3 41 All dimensions in millimetres. Figure 10.1 DMU10 (OEM) Installation Drawing © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 21 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 45 37 18.5 16 9.5 26 3x Ø 3.1 3.0 2.024 x3.0DP 2.012 3.5 All dimensions in millimetres. 34.5 0.5 Ø 2.024 2.012 x3DP 2x R Figure 10.2 DMU10 (Module) Installation Drawing + Pitch (P) +Y +X + Roll (R) +Z + Yaw (Y) Figure 10.3 Axis Definitions © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 22 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com 11 DMU10 MEMS Sensor Internal Construction and Theory of Operation Construction The DMU10 uses three MEMS rate and acceleration Combi-Sensors providing three gyroscopes and six accelerometers. Each Combi-Sensor comprises six main components; Silicon MEMS Single-Axis Angular Rate Sensor, Silicon On Glass (SOG) Dual-Axis MEMS Accelerometer, Silicon Pedestal, ASIC Package Base and Lid. The MEMS Sensors, ASIC and Pedestal are housed in a hermetically sealed package cavity with a nitrogen back-filled partial vacuum, this has particular advantages over sensors supplied in plastic packages which have Moisture Sensitivity Level limitations. An exploded drawing of a Combi-Sensor showing the main components is given in Figure 11.1 below. CM PPY S300 Y Mad MMLLL e In JapaLRDD n Vacuum Cavity Seal Ring Lid YYM MLL LL_X XXX Bond Wires MEMS Ring Pedestal Dual-Axis Accelerometer ASIC Package Base C.G. 18542 Figure 11.1 Combi-Sensor Main Components Silicon MEMS Ring Sensor (Gyro) The 3mm diameter by 65μm thick silicon MEMS ring is fabricated by Silicon Sensing using a DRIE (Deep Reactive Ion Etch) bulk silicon process. The annular ring is supported in free-space by eight pairs of ‘dog-leg’ shaped symmetrical spokes which radiate from a central 1mm diameter solid hub. The bulk silicon etch process and unique patented ring design enable close tolerance geometrical properties for precise balance and thermal stability and, unlike other MEMS gyros, there are no small gaps to create problems of interference and stiction. These features contribute significantly to DMU10’s bias and scale factor stability over temperature, and vibration and shock immunity. Another advantage of the design is its inherent immunity to acceleration induced rate error, or ‘g-sensitivity’. Piezoelectric (strain) thin film actuators/transducers are attached to the upper surface of the silicon ring perimeter and are electrically connected to bond pads on the ring hub via tracks on the spokes. These actuate or ‘drive’ the ring into its Cos2 mode of vibration at a frequency of 22kHz or detect radial motion of the ring perimeter either caused by the primary drive actuator or by the coriolis force effect when the gyro is rotating about its sensing axis. There is a single pair of primary drive actuators and a single pair of primary pick-off transducers, and two pairs of secondary pick-off transducers. The combination of transducer technology and eight secondary pick-off transducers improves the DMU10’s signal-to-noise ratio, the benefit of which is a very low-noise device with excellent bias over temperature performance. Silicon MEMS Dual-Axis Accelerometer Figure 11.2 Combi-Sensor (Lid Removed) The Combi-Sensor dual-axis open loop accelerometer is a one-piece resonating silicon MEMS structure anodically bonded to top and bottom glass substrates to form a hermetically sealed Silicon on Glass (SOG) wafer sub-assembly. The same DRIE bulk silicon process as used to create the gyro in is used to create two orthogonal finger-like spring/seismic proof mass structures, each measuring 1.8mm square, and with a resonant frequency of 2.9kHz. Figure 11.3 shows a schematic cross section through the SOG wafer. © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 23 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com Capacitive drive and pick-off signals are transmitted by wire bond interconnections, in through-glass vias, between the metallised transducer plates on the MEMS proof mass and the ASIC. Multiple inter-digitated fingers create increased capacitance thus enabling a high signal-to-noise ratio. The fingers are tapered to increase the resonant frequency and also have a high aspect ratio to provide highly stable performance. The differential gaps between the static electrode fingers and those of the proof mass provide an air squeeze film with nearcritical damping. Control of the accelerometer is handled by the ASIC. Support flexure Glass Substrates Seismic proof mass Through-glass via Cavity Silicon C.G. 18538 Figure 11.3 Schematic Section of the Silicon On Glass Accelerometer MEMS Wafer Sub-Assembly Pedestal The hub of the MEMS gyro ring is supported above the ASIC on a 1mm diameter cylindrical silicon pedestal, which is bonded to the ring and ASIC using an epoxy resin. ASIC The ASIC is a 5.52mm x 3.33mm device fabricated using 0.35μm CMOS process. ASIC and MEMS are physically separate and are connected electrically by using gold bond wires and thus the ASIC has no MEMS-to-ASIC internal tracking, meaning there is reduced noise pick-up and excellent EMC performance. Gold bond wires also connect the ASIC to the internal bond pads on the Package Base. Package Base and Lid The LCC ceramic Package Base is a multi-layer aluminium oxide construction with internal bond wire pads connected through the Package Base via integral multi-level tungsten interconnects to a series of external solder pads. Similar integral interconnects in the ceramic layers connect the Lid to Vss, thus the sensitive elements are inside a Faraday shield for excellent EMC. Internal and external pads are electroplated gold on electroplated nickel. The Package Base incorporates a seal ring on the upper layer onto which a Kovar ® metal Lid is seam welded using a rolling resistance electrode, thus creating a totally hermetic seal. Unlike other MEMS Inertial Sensor packages available on the market, the DMU10 Combi Sensor has a specially developed seam weld process which eliminates the potential for internal weld spatter. Inferior designs can cause dislodged weld spatter which affects gyro reliability due to interference with the vibratory MEMS element, especially where the MEMS structure has small gaps, unlike Combi-Sensor with its large gaps as described above. Theory of Operation (Gyro) The rate sensor is a solid-state device and thus has no moving parts other than the deflection of the ring itself. It detects the magnitude and direction of angular velocity by using the ‘coriolis force’ effect. As the gyro is rotated coriolis forces acting on the silicon ring cause radial movement at the ring perimeter. There are eight actuators/transducers distributed evenly around the perimeter of the silicon MEMS ring. Located about its primary axes (0° and 90°) are a single pair of ‘primary drive’ actuators and a single pair of ‘primary pick-off’ transducers. Located about its secondary axes (45° and 135°) are two pairs of ‘secondary pick-off’ transducers. The ‘primary drive’ actuators and ‘primary pick-off’ transducers act together in a closed-loop system to excite and control the ring primary operating vibration amplitude and frequency (22kHz). Secondary ‘pick-off’ transducers detect radial movement at the secondary axes, the magnitude of which is proportional to the angular speed of rotation and from which the gyro derives angular rate. © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 24 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com The transducers produce a double sideband, suppressed carrier signal, which is demodulated back to a baseband. This gives the user complete flexibility over in system performance, and makes the transduction completely independent of DC or low frequency parametric conditions of the electronics. PPO SPO SPO PD PD Referring to Figures 11.4(a) to 11.4(d) Figure 11.4(a) shows the structure of the silicon MEMS ring. Figure 11.4(b) shows the ring diagrammatically, the spokes, actuators and transducers removed for clarity, indicating the Primary Drive actuators (single pair), Primary Pick-Off transducers (single pair) and Secondary Pick-Off transducers (two pairs). In Figure 11.4(b) the annular ring is circular and is representative of the gyro when unpowered. SPO SPO PPO C.G 18399 Figure 11.4(b) ν When powered-up the ring is excited along its primary axes using the Primary Drive actuators and Primary Pick-Off transducers acting in a closed-loop control system within the ASIC. The circular ring is deformed into a ‘Cos2θ’ mode which is elliptical in form and has a natural frequency of 22kHz. This is depicted in Figure 11.4(c). In Figure 11.4(c) the gyro is powered-up but still not rotating. At the four Secondary Pick-Off nodes located at 45° to the primary axes on the ring perimeter there is effectively no radial motion. Zero Radial Motion SPO ν If the gyro is now subjected to applied angular rate, as indicated in Figure 11.4(d), then this causes the ring to be subjected to coriolis forces acting at a tangent to the ring perimeter on the primary axes. These forces in turn deform the ring causing radial motion at the Secondary Pick-Off transducers. It is the motion detected at the Secondary Pick-off transducers which is proportional to the applied angular rate. The signal is demodulated with respect to the primary motion, which results in a low frequency component which is proportional to angular rate. All of the gyro control circuitry is hosted in the ASIC. A block diagram of the ASIC functions is given in Figure 1.1 in Section 1. Cos2θ Vibration Mode at 22kHz ν ν C.G 18400 Figure 11.4(c) ν Fc Resultant Radial Motion Fc = Coriolis Force PPO+ SPOSPO+ ν SPO- Applied Rate SPO+ PD+ PDPD+ ν Fc PD- Fc SPO+ SPO- SPO+ SPOPPO+ Figure 11.4(a) C.G 18398 ν C.G 18400 Figure 11.4(d) © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 25 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com Theory of Operation (Accelerometer) The accelerometer contains a seismic ‘proof mass’ with multiple fingers suspended via a ‘spring’, from a fixed supporting structure. The supporting structure is anodically bonded to the top and bottom glass substrates and thereby fi xed to the sensor package base. When the accelerometer is subjected to a linear acceleration along its sensitive axis, the proof mass tends to resist motion due to its own inertia, therefore the mass and it’s fingers becomes displaced with respect to the interdigitated fi xed electrode fingers (which are also fi xed to glass substrates). Air between the fingers provides a damping effect. This displacement induces a differential capacitance between the moving and fi xed silicon fingers which is proportional to the applied acceleration. 88kHz reference Electrode 2 Signal proportional to movement of proof mass Out of Phase Square Wave at 88kHz on Electrode 2 Sensing axis Amplifier Electrode 1 Demodulator Low pass filter In Phase Square Wave at 88kHz on Electrode 1 Output signal C.G. 18540 Figure 11.5(b) Schematic of Accelerometer Control Loop Capacitor plate groups are electrically connected in pairs at the top and bottom of the proof mass. In-phase and anti-phase waveforms are applied by the ASIC separately to the ‘left’ and ‘right’ finger groups. The demodulated waveforms provide a signal output proportional to linear acceleration. Figures 11.5(a) and 11.5(b) provide schematics of the accelerometer structure and control loop respectively. Sensing axis Fixed Electrode 1 Fixed support Fixed Electrode 2 Proof mass (includes fingers) C.G. 18613 Figure 11.5(a) Schematic of Accelerometer Structure © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 26 DMU10-00-0100-132 Rev 4 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com Notes © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. DMU10-00-0100-132 Rev 4 Page 27 DMU10 Technical Datasheet Six Degrees of Freedom Precision MEMS Inertial Measurement Unit www.siliconsensing.com Notes Silicon Sensing Systems Limited Clittaford Road Southway Plymouth Devon PL6 6DE United Kingdom Silicon Sensing Systems Japan Limited 1-10 Fuso-Cho Amagasaki Hyogo 6600891 Japan T: F: E: W: T: F: E: W: +44 (0)1752 723330 +44 (0)1752 723331 [email protected] siliconsensing.com +81 (0)6 6489 5868 +81 (0)6 6489 5919 [email protected] siliconsensing.com Specification subject to change without notice. © Copyright 2015 Silicon Sensing Systems Limited All rights reserved. Printed in England 06/2015 Date 09/06/2015 DMU10-00-0100-132 Rev 4 DCR No. 710009189 © Copyright 2015 Silicon Sensing Systems Limited. All rights reserved. Silicon Sensing is an Atlantic Inertial Systems, Sumitomo Precision Products joint venture company. Specification subject to change without notice. Page 28 DMU10-00-0100-132 Rev 4