KVH DSP-1750 Fiber Optic Gyro

Transcription

1 KVH DSP-1750 Fiber Optic Gyro Dual Axis Standard Rate Digital Output Technical Manual DSP-1750

2 DSP-1750 Fiber Optic Gyro Technical Manual (Dual-Axis Version) This technical manual supports KVH Industries standard-rate DSP-1750 dual-axis interferometric fiber optic gyro with digital asynchronous output. Technical and performance specifications, interface data, testing and mounting guidelines, and a brief troubleshooting guide are included. Please direct questions, comments, or suggestions to: KVH Industries, Inc. 50 Enterprise Center Middletown, RI USA Tel: Fax: fogsupport@kvh.com Internet: If you have any comments regarding this manual, please them to manuals@kvh.com. Your input is greatly appreciated! KVH Part # Rev. D 2011, KVH Industries, Inc., All rights reserved. Protected by U.S. and foreign patents

3 KVH is a registered trademark of KVH Industries, Inc. Nanovate is a trademark of Integran Technologies, Inc.

4 Table of Contents Product Specifications...1 Storage and Handling...6 Maintenance...6 Output Orientation...6 Sensor Cable...7 Interface Connector...8 Power Requirements...9 Digital Data Output...10 Wiring the Gyro...13 Testing the Gyro...14 Mounting the Gyro...16 Troubleshooting...19 Technical Support...19 Appendix A Patent Protection...21 i

5 Product Specifications Product specifications are listed in Figure 1. Figure 1 Specifications Attribute Rating Performance Maximum Input Rate ±490 /sec Scale Factor, Nominal 1 (±0.2%) Scale Factor Non-linearity (@25 C) Scale Factor vs. Temperature Bias Offset (@25 C) Bias Stability (@25 C)* Bias vs. Temperature Bias Magnetic Sensitivity Angle Random Walk* (@25 C) Initialization Time (@25 C) Full Performance Time Data Rate 0 to ±150 /sec input rate: 200 ppm, 1 Full input rate: 500 ppm, ppm, 1 Unshielded: ±10 /hr max. Magnetically Shielded: ±2 /hr max /hr 3 /hr, 1 Unshielded: 15 /hr/gauss Magnetically Shielded: 2 /hr/gauss 0.8 /hr/ Hz / hr 3 seconds 5 minutes Kbps, ±200 ppm Bandwidth (-3 db) 440 Hz (±4%) Axis Misalignment 4 mrad Sampling Rate/Output Rate 1,000 Hz (±4%) Motion to Output Latency 1.3 msec *NOTE: Bias Stability and Angle Random Walk determined by Allan Variance Method. 1

6 Figure 1 Specifications (Continued) Attribute Rating Electrical (see Power Requirements on page 9 for additional power requirements) Input Voltage (±5%) Total Power +8 to +15 VDC, 100 ma max. -8 to -15 VDC, 100 ma max. +5 VDC, 500 ma max W typical, 5.5 W max. Physical Dimensions (optical sensor) Dimensions (PCB stack) Weight (optical sensor) Weight (PCB stack) Unshielded: ø1.715" x 0.83" h max. (43.6 mm x 21.1 mm) Magnetically Shielded: ø1.81" x 0.925" h max. (46.0 mm x 23.5 mm) ø2.870" x 0.565" h max. (72.9 mm x 14.4 mm) Unshielded: 0.10 lb (45 g) max., each Magnetically Shielded: 0.14 lb (65 g) max., each 0.10 lb (45 g) max. Environmental Operating Temperature Thermal Rate Storage Temperature Shock (functional) Shock (gunfire) Shock (endurance) Vibration, Random (operational) Vibration, Random (endurance) Altitude (operational) Humidity (operational) MTBF (ground mobile) -40 C to +75 C (-40 F to +167 F) 1 C/min -51 C to +85 C (-60 F to +185 F) 25 g, 11 msec (sawtooth) 55 g, 1 msec (1/2 sine) 40 g, 11 msec (sawtooth) 8 g rms, 20-2,000 Hz 12 g rms, 20-2,000 Hz -1,000 to 40,000 ft ( m to 12,200 m) 95% at 35 C (95 F), 48 hrs 22,000 hrs 2

7 IMPORTANT! The gyro s optical sensors and PCB stack are calibrated at the factory as a matched set. The labels on the optical sensors denote the channels and the serial numbers of their associated PCBs. To ensure proper performance, keep the gyro s components together. Do not install mismatched optical sensors and PCBs! The gyro consists of two optical sensors connected to an external PCB stack (processor PCB mated to channel PCB). The optical sensors may be equipped with optional magnetic shielding (Nanovate plating and PCB cover) for improved performance within a magnetic field. The PCB stack is identical for both variants. Figure 2 on page 4 illustrates the dimensions and mounting holes of the unshielded sensor and PCB stack. Figure 3 on page 5 illustrates the dimensions and mounting holes of the magnetically shielded sensor and PCB stack. All dimensions are shown in inches [millimeters] format. NOTE: For simplification, all other illustrations in this manual show the unshielded optical sensor. 3

8 Figure 2 Interface Control Drawing (ICD) - Unshielded Version Optical Sensor (1 of 2), Bottom View Ø1.715 [Ø43.56] Max. 3 x #4-40 Mounting Holes [5.08] Max. Thread Ø0.948 [Ø24.08] 3 x 120 PCB Stack, Top View Ø2.870 [Ø72.90] Max [27.99] [55.50] Max [34.54] 4 x Ø0.094 [Ø2.39] Through Holes Optical Sensor, Side View [21.08] Max. PCB Stack, Side View [2.87] Max [14.35] Max. Processor PCB Channel PCB [4.32] Max. (Connector) 4

9 Figure 3 Interface Control Drawing (ICD) - Magnetically Shielded Version Optical Sensor (1 of 2), Bottom View Ø1.810 [Ø45.97] Max. 3 x #4-40 Mounting Holes [5.08] Max. Thread Ø0.948 [Ø24.08] 3 x 120 PCB Stack, Top View Ø2.870 [Ø72.90] Max [27.99] [55.50] Max. Optical Sensor, Side View [34.54] 4 x Ø0.094 [Ø2.39] Through Holes [23.50] Max. PCB Stack, Side View [2.87] Max [14.35] Max. Processor PCB Channel PCB [4.32] Max. (Connector) 5

10 Storage and Handling The DSP-1750 gyro may be stored in a location with an environmental temperature between -60 F and 185 F (-51 C and 85 C). Ideally, the unit should be stored at a room temperature of approximately 70 F (21 C). The DSP-1750 gyro is a sensitive measuring device. Take normal safety precautions when handling the optical sensors or PCB stack to ensure the integrity of the device. During unpacking and installation, proper ESD handling procedures should be enforced. IMPORTANT! If you need to ship the gyro to another location, be sure to reinstall it in its original plastic shipping tray and pack it in a larger box with appropriate packing materials. Maintenance The DSP-1750 gyro s optical sensors are supplied as sealed units; there are no field maintainable components. Opening the enclosures will void the warranty and may violate the contract under which the unit was supplied. Output Orientation Each of the DSP-1750 gyro s optical sensors detects rotation around an axis perpendicular to the plane of its base. Looking at an optical sensor from overhead, a counter-clockwise rotation will produce a positive output (see Figure 4). Figure 4 Output Orientation (Top View) 6 Sensor Cable

11 Sensor Cable A 5.9" (150 mm) ribbon cable connects each optical sensor to the PCB stack s channel PCB at the connector locations shown in Figure 5. After installing the gyro, be sure to secure these cables to the mounting surface as close as possible to each connector (at the sensors and the PCB) to relieve strain and help protect them from vibration. Also be sure the ribbon cables are fully engaged with the connectors at the sensors and PCB. You should hear a slight click when you connect the cable. Figure 5 Sensor Cable Connections Optical Sensor (Channel 2) Channel PCB Sensor Cables Optical Sensor (Channel 1) 7

12 Interface Connector The gyro s channel PCB is equipped with a 15-pin interface connector of the following type: Tyco part number Figure 6 shows the interface connector pins and the function of each pin. Figure 6 Interface Connector Pins on Channel PCB v Pin Type Function 1 Power +15 VDC Power Input 2 Power -15 VDC Power Input 3 Power ±15 VDC Power Return 4 RS422 Receive (Rxd-) 5 RS422 Receive (Rxd+) 6 RS422 Transmit (Txd+) 7 RS422 Transmit (Txd-) 8 RS422 Signal Ground Pin 1 Pin 15 9 Power +5 VDC Power Input 10 Power +5 VDC Power Return 11 - Do Not Connect 12 - Do Not Connect 13 - Do Not Connect 14 - Do Not Connect 15 - Do Not Connect NOTE: For a suitable mating connector, use a connector of the following type: Molex part number

13 Power Requirements IMPORTANT! Be sure to follow all of the guidelines provided in this section. The gyro can become inoperable and/or damaged if all of the power requirements described in this section are not met. As noted in Product Specifications on page 1, the DSP-1750 gyro requires three separate DC power supplies: +5 VDC +15 VDC (+8 to +15 VDC) -15 VDC (-8 to -15 VDC) The return path for all three power supplies reference a common ground point within the gyro. To ensure proper operation and avoid potential damage to the gyro, make sure all three power supplies maintain a stable voltage that is clean of noise and held within the tolerances specified in Product Specifications on page 1. In addition, make sure each power supply powers on and off in the proper sequence, as described below. Power-on Requirements The +5 VDC supply must rise above +4 VDC before the +15 VDC and -15 VDC supplies rise above +5 VDC and below -5 VDC, respectively. All three supplies should transition smoothly and monotonically to their required voltage levels. All three supplies should reach their required voltage levels within 200 msec of each other. Power-off Requirements The +5 VDC supply must maintain its voltage level above +4 VDC until the +15 VDC and -15 VDC supplies fall below +2 VDC and above -2 VDC, respectively. All three voltages should settle to within 100 mv of the common ground reference (and their individual returns) in less than 2 seconds. 9

14 Digital Data Output Interface connector pins 4 through 8 provide a 1,000 Hz asynchronous serial interface to the gyro. This interface has the following characteristics: Type: RS422 Baud Rate: 115,200 Parity: None Data Bits: 8 Stop Bits: 1 Flow Control: None Figure 7 defines the gyro s output format and burst rate. Figure 7 Gyro Digital Output Format Output Burst Rate Format Characteristics 1,000/second (approximate*) Each character contains 10 bits: 1 start bit (Space, binary 0) 8 data bits (1 message byte, starting with LSB) 1 stop bit (Mark, binary 1) An idle line is always marking (in a binary 1 state). Six characters in sequence constitute a basic message. *NOTE: The output burst rate might vary by ±5 percent between gyros. There is also variation over temperature of approximately ±0.2 percent. 10

15 Message Structure The output message contains 48 bits (6 bytes), excluding start and stop bits. The most significant byte is sent first. The least significant bit of each byte is sent first. Figure 8 and Figure 9 define the message bits. Figure 8 Message Bits Bit(s) Usage Values 47, 46 Synchronization See Synchronization on page Message Validity, Channel 2 axis 44 Message Validity, Channel 1 axis Rate Data, Channel 2 axis 21-0 Rate Data, Channel 1 axis 0 = Hardware BIT signal is low or contents are invalid. 1 = Hardware BIT OK, contents are valid. Contents are in two s complement format. LSB represents /s or 1.72 /hr. Channel 2 (C2) axis: Bit 43 = MSB. Channel 1 (C1) axis: Bit 21 = MSB. Figure 9 Message Structure = Start Bit = Stop Bit Note: The least significant bit (LSB) is sent first. Byte 1 Byte C1 Valid C2 Valid Sync Byte Byte C2 Data C1 Data C2 Data C2 Data C2 Data Byte 5 Byte C1 Data 11

16 Synchronization Message bits 46 and 47 make up the synchronization field for each message. These bits conform to an eight-bit, continuously repeating pattern ( ), as shown in Figure 10. Figure 10 Pattern of Synchronization Bits 1st Message 2nd Message 3rd Message 4th Message This synchronization pattern allows you to design a receiver algorithm that can detect the first byte of a message. For example, you could create a state machine with two modes: Acquisition and Locked. In Acquisition mode, the state machine would examine the seventh and eighth bits of each byte. Once it finds a byte position that exhibits the defined synchronization pattern for 10 cycles in a row, and no other byte position has exhibited the pattern for more than 3 of the last 10 cycles, the state machine would designate that byte position as the first byte in the six-byte message. The state machine would then enter Locked mode. In Locked mode, the state machine would continue to monitor each byte. If the byte position designated as first does not match the synchronization pattern for more than 3 out of 10 cycles, and a different byte position matches 7 or more, the state machine would then designate the different byte position as the first byte. 12

17 Wiring the Gyro Use the wiring diagram in Figure 11 as a guide to connect the gyro to your application. Figure 11 Wiring Diagram for Digital Operation Pin Power Power Power RX- RX+ TX+ TX- Signal Ground Power Power Do not connect Do not connect Do not connect Do not connect Do not connect DC Supply +15 VDC* -15 VDC* 15V Return Customer Interface (RS422) +5 VDC 5V Return DC Supply * Acceptable ranges: +8 to +15 VDC, -8 to -15 VDC IMPORTANT! Be sure to follow all of the guidelines provided in Power Requirements on page 9. The gyro can become inoperable and/or damaged if all of the necessary power requirements are not met. 13

18 Testing the Gyro Before connecting and mounting the gyro to your system, a simple familiarization test is suggested if this is your first introduction to the product. This test will also verify proper unit operation and assist in troubleshooting. Equipment Needed to Test Gyro +8 to +15 VDC (±5%) power supply -8 to -15 VDC (±5%) power supply +5 VDC (±5%) power supply Interface cable with a Molex connector on one end and an RS422 connector on the other end Computer with an RS422 input and a customer-supplied test acquisition program TIP: Use a standard RS422-to-RS232 converter to connect the gyro to your computer s serial port. IMPORTANT! The gyro s components are static-sensitive. Take proper grounding precautions before handling (for example, use an ESD wrist strap). Test Procedure Follow the steps below to test the gyro for proper operation. 1. Place the DSP-1750 optical sensors on a flat surface with the mounting surfaces facing down. 2. Make sure the sensor cables are connected between the optical sensors and the channel PCB, and make sure the channel PCB is properly mated to the processor PCB. 3. Connect your computer (via a compatible RS422-to- RS232 converter) to the gyro s RS422 pins as shown in Figure 11 on page 13. IMPORTANT! Be sure to follow all of the guidelines provided in Power Requirements on page 9. The gyro can become inoperable and/or damaged if all of the necessary power requirements are not met. 14

19 4. Connect the +15 VDC (+8 to +15 VDC), -15 VDC (-8 to -15 VDC), and +5 VDC power supplies to the gyro as shown in Figure 11 on page Select the interface cable s serial port. Open the test data acquisition program and select the following program settings: 115,200 baud 8 data bits 1 stop bit No parity No flow control 6. With the optical sensors held stationary, the indicated mean (30-second average) input rate should be less than ±0.1 /s, excluding Earth rate. If no data is received, check the wiring for a proper data connection. TIP: To calculate the Earth rate for your geographic area, use the following formula: Earth rate = x sin (latitude). Northern latitudes are positive and southern latitudes are negative. 7. Grasp one of the two optical sensors and slowly rotate it counter-clockwise (see Figure 12). The output for that sensor s channel should indicate a positive change. Figure 12 Output Orientation (Top View) Sensor Cable 8. Slowly rotate the optical sensor in the opposite (clockwise) direction. The output data should indicate a negative change. 9. After the initial 5-second startup, the data message s Validity bit (bit 44 for channel 1, bit 45 for channel 2) should show binary 1 ( data valid ) at all times. If the Message Validity bit shows binary 0 ( fault ), the gyro has malfunctioned. 10. Repeat steps 7-9 to test the second optical sensor. 15

20 Mounting the Gyro First, remove the optical sensors and PCB stack from their plastic shipping tray (secured by four #2-56 Phillips screws and six #4-40 Phillips screws). IMPORTANT! The gyro s components are static-sensitive. Take proper grounding precautions before handling (for example, use an ESD wrist strap). Mount the base of each optical sensor to your mounting structure using three stainless steel screws at the mounting hole locations shown in Figure 13. Be sure the screws engage the threads of the mounting holes to at least one screw body diameter (0.112" [2.85 mm] min., 0.200" [5.08 mm] max.). Tighten the screws to 7 in-lbs of torque. IMPORTANT! Be sure to mount the optical sensors in the proper orientation for your application perpendicular to the desired sensing axes. Figure 13 Optical Sensor Mounting Holes, Bottom View 3 x #4-40 Mounting Holes [5.08] Max. Thread Ø0.948 [Ø24.08] 3 x

21 Make sure the processor PCB is still securely mated to the channel PCB. Then mount the PCB stack to your mounting structure using four #2-56 screws through the hole locations shown in Figure 14. Use standoffs to ensure the PCB components do not come into contact with the mounting surface. Tighten the screws to 3 in-lbs of torque. Figure 14 PCB Stack Mounting Holes, Bottom View [27.99] [34.54] 4 x #2-56 Mounting Holes The mounting surface should be flat, less than 0.005" (0.127 mm) peak-to-peak. The material should be greater than 0.2" (5 mm) thick with the overall stiffness of the structure designed to be compatible with the natural frequency specified for the gyro or as required for the specific installation. The chassis ground must be mechanically connected to mounting hole #1 on the channel PCB, as shown in Figure 15, for proper shielding. Figure 15 Ground Point on Channel PCB Mounting Hole #1, PCB Ground Point NOTE: Performance of the gyro as a sensor is determined by the design of the mounting structure as well as the gyro s mechanical components. The mounting structure material should be fabricated from a material, such as aluminum, that has a low thermal time constant. In addition, the gyro should not be mounted near equipment that generates time-varying magnetic fields (e.g., stepper motors, servo motors, or solenoids). 17

22 Cable Strain Relief Once you have mounted the gyro, make sure the ribbon cables are fully engaged with the connectors on the optical sensors and channel PCB. Then secure each cable to the mounting structure in two locations, as close as possible to each connector, to relieve strain and help protect it from vibration (see Figure 16). Figure 16 Optimal Strain Relief Locations on Sensor Cables Optical Sensor (Channel 2) Channel PCB Optical Sensor (Channel 1) 18

23 Troubleshooting This section is intended to provide a simple means of determining if a problem exists in the KVH DSP-1750 gyro and assumes that the unit has passed the bench testing described earlier. IMPORTANT! The DSP-1750 optical sensors are supplied as sealed units. Opening the enclosure voids the warranty and may violate the contract under which the unit was supplied. The warranty does not apply if the unit has been damaged by misuse or as the result of service or modification other than by KVH Industries. Figure 17 Basic Troubleshooting Symptom Possible Cause Action No output No DC power Check power (measure at the PCB). Erratic or low output Damaged or disconnected cable Faulty ground Magnetic field near gyro sensor Check the interface cable connecting the channel PCB to your system. Also check the ribbon cables* connecting the optical sensors to the channel PCB. Ground shield at gyro end only. Check for new wiring or equipment. High noise Ground loop Check grounds and grounding. *NOTE: Replacement ribbon cables are available from KVH. Order KVH part number Technical Support For technical support, please your question or a description of your problem to fogsupport@kvh.com. 19

24 Appendix A Patent Protection One or more of the following U.S. and international patents* protect the technology in KVH fiber optic gyros: KVH Patent Numbers DE US 5,739,944 EP 1,314,002 US 5,768,462 EP T2 US 6,041,149 US 4,773,759 US 6,134,356 US 5,120,130 US 5,153,676 US 6,351,310 B1 US 6,370,289 B1 US 5,340,371 US 6,429,939 US 5,444,534 US 6,718,097 US 5,481,358 US 6,763,153 US 5,552,887 US 6,836,334 *Additional patents pending 21

25 KVH Industries Limited Warranty DSP-1750 LIMITED WARRANTY ON HARDWARE KVH Industries, Inc. warrants the KVH Fiber Optic Gyro purchased against defects in materials and workmanship for a period of ONE (1) year from the date of original retail purchase by the original purchaser. If you discover a defect, KVH will, at its option, repair, replace or refund the purchase price of the product at no charge to you, provided you return it during the warranty period, transportation charges prepaid, to the factory direct. Please attach your name, address, telephone number, a description of the problem and a copy of the bill of sale or sales receipt as proof of date of original retail purchase, to each product returned to warranty service. This Limited Warranty does not apply if the product has been damaged by accident, abuse, misuse, or misapplication or has been modified without the written permission of KVH; if any KVH serial number has been removed or defaced; or if any factory-sealed part of the system has been opened without authorization. THE EXPRESS WARRANTIES SET FORTH ABOVE ARE THE ONLY WARRANTIES GIVEN BY KVH WITH RESPECT TO ANY PRODUCT FURNISHED HEREUNDER; KVH MAKES NO OTHER WARRANTIES, EXPRESS, IMPLIED OR ARISING BY CUSTOM OR TRADE USAGE, AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. SAID EXPRESS WARRANTIES SHALL NOT BE ENLARGED OR OTHERWISE AFFECTED BY TECHNICAL OR OTHER ADVICE OR SERVICE PROVIDED BY KVH IN CONNECTION WITH ANY PRODUCT. KVH s liability in contract, tort or otherwise arising out of or in connection with any product shall not exceed the price paid for the product. IN NO EVENT SHALL KVH BE LIABLE FOR SPECIAL, PUNITIVE, INCIDENTAL, TORT OR CONSEQUENTIAL DAMAGES OR LOST PROFITS OR GOODWILL (INCLUDING ANY DAMAGES RESULTING FROM LOSS OF USE, DELAY IN DELIVERY OR OTHERWISE) ARISING OUT OF OR IN CONNECTION WITH THE PERFORMANCE OR USE OR POSSESSION OF ANY PRODUCT, OR ANY OTHER OBLIGATIONS RELATING TO THE PRODUCT, EVEN IF KVH HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. If any implied warranty, including implied warranties of merchantability and fitness for a particular purpose, cannot be excluded under applicable law, then such implied warranty shall be limited in duration to ONE (1) YEAR from the date of the original retail purchase of this product by the original purchaser. Some states do not allow the exclusion or limitation of implied warranties or liability for incidental or consequential damages, so the above limitations may not apply to you. This warranty gives you specific legal rights, and you may also have other rights which vary from state to state.

26 KVH Industries, Inc. 50 Enterprise Center Middletown, RI U.S.A. Phone: Fax: Internet: DSP1750_standard_2axis_cover KVH is a registered trademark of KVH Industries, Inc.