Acoustic Oceanographic Buoy v2 - CINTAL
Contents
1. Se E Connector A x ry Top Thimble txi 35mm 15 Thermistor Y AES 1 E S Hydrophone 3 Y b 2 8 Polyamid protection sleeve E E m o y 3 E 8 ci D a Y Y HER 416 17 E j 20mm 5 Strength member ka Y gemm Bottom lead weight CD Figure 2 1 AOB2 analog array with dimensions line to transmit the signal to the surface buoy s electronics The thermistor sensors are digital devices that transmit the temperature values through a single wire serial digital network that requires only two wires The signals received at the hydrophone modules are available at two connectors on the top of the array A third connector is used for the thermistor bus The cables are protected by a polyamide sleeve one internal strength member cable is used to handle the vertical mechanical forces applied to the array and one ballast weight is placed on the bottom to stretch the array and keep nearly vertical The result is a thin and compact array with all the sensors at precise positions figure 9 10 CHAPTER 2 OVERALL DESCRIPTION 2 1 In the AOB2 system figure 2 2 the array is attached to the buoy s bottom cover support ring and the signal connectors are attached to the buoy s top cover The buoy is floating at the sea surface and with the help of the ballast the array is kept as much vertical as possible Array Figure 2 2 AOB2 system overview analog array wit2. NrATddns ui3MOd m mmm auon anos 1001 ano ay i Co L I A oy E e e 2 io T uar lt 8 t 1C CITCUI s electroni 1n thermistor chai Figure 4 24 4 3 THERMISTOR CHAIN ELECTRONICS 39 4 3 11 3 Power supply To work the circuit needs a voltage of 5V The 12V voltage is only necessary if the microcontroller s software needs to write any values in the 1 wire slave devices EEPROM if not the 12V input may be connected to 5V In the current system the slave devices EEPROM is not used and in the 12V input receives 5V Refer to DS2480B datasheet 14 PGM PGC PGD MCLR GND Vcc 5V 12V Gnd ICSP connector Power supply Input DS2480B PGM PGC PGD MCLR GND 5V 12V Gnd PROGRAM PIC Figure 4 25 PIC programming schematic 40 CHAPTER 4 SYSTEM REFERENCE 4 3 12 Thermistor reading software The software for reading in the data provided by the digital thermistor chain is separated in two parts one is the low level piece of software running in the PIC of the Master board card and the other is the RS 232 port reading from the AOB2 CPU 4 3 12 1 PIC software The acquisition program is explained in figure 4 26 s flowchart For detailed flowcharts refer to appendix E 2 For further details about 1 wire besides D818B20 PAR datasheet 9 and DS2480B datasheet 14 refer to Maxim aplication notes AN148 11 AN27 12 AN155 15 and app192 16 4 3 12 2 AOB2 thermi
3. Contents List of Figures 1 Introduction 2 Overall Description 3 User Manual pilo dn aod aeu OB s erster e rope p bue ses uk ia 3 2 Hardware Overview a A a R ND 3 3 Pre deployment procedureg a cid eee AA b dc Ss Jub Hardware Qus do credo m Re ID era ea Ii es 3 3 2 Software e E eo oue at As CH i etia e AI 3 4 Deployment recover and post deployment procedures EX IIIa ata BA das maree aristas Wg Sb Roo SOL IDE sa a ES E REDE DA A Ee i System Reference d Mechanical moe eian Ta R A E EE uS A 4 1 1 rotna dae aa 2127 Top Thimble Va orario A e Levi Ee RS Aris o A bt et dyn A eus oh M de o MS 4 1 4 Strength Member decor Ballasts noto moon wore y RATOS aa ae 4 1 6 Hydrophone Protection Case xsara Ir Oa bere ede 4 2 Hydtophone electronics co css gia nia i RUE Eon v CAD AD Ali Hydrophon s eps fe Go ed 3G eid oie doe mue Pardo ded 3 4 2 2 EMPRESA A e EC RU EROR OS 4 2 3 Cables and Connectors AAA 4 3 Thermistor chain electronics e ce ER Da Ko ee un OR d 4 3 1 Overview and SEMP es b db xe 0o al xem e A Dr tyi dee 2 12 PONCISUD as STE A PAD AA YDYN DA S S du draps 433 tatus LEDS a us Gh ks E 4 3 4 Serial Interface Configuration suis gi se dee doe Persa sp gs 4 3 5 Serial Interface Messages coat ae Lu i 4310 OSLO E baie alibi d TEN MODUS a eec doe Pao a Le 4 3 8 Data packet ug duos urhe ce ded e M ALII wo lita ZORRO Ehi pela wd ADI o AAA De NAC 4 3 10 TS Wire Bus Master sure ola dg 43T Electronic
4. Table New Index Current Table Current CRC xor Input New CRC Index Data Value 0000 0000 00h 0000 0010 02h 00h xor 02h 02h 2 Table 2 188 1011 1100 BCh 1011 1100 BCh 0001 1100 1Ch BCh xor 1Ch A0h 160 Table 160 175 1010 1111 AFh 1010 1111 AFh 1011 1000 B8h AFh xor B8h 17h 23 Table 23 30 0001 1110 1Eh 0001 1110 1Eh 0000 0001 01h 1Eh xor 01h 1 Fh 31 Table 31 220 1101 1100 DCh 1101 1100 DCh 0000 0000 00h DCh xor 00h DCh 220 Table 220 244 1111 0100 F4h 1111 0100 F4h 0000 0000 00h F4h xor 00h F4h 244 Table 244 21 0001 0101 15h 0001 0101 15h 0000 0000 00h 15h xor 00h 15h 21 Table 21 162 1010 0010 A2h 1010 0010 A2h 1010 0010 A2h A2h xor A2h 0h 0 Table 0 0 0000 0000 00h Table 4 11 table lookup method for computing DOW CRC After power up the temperatures acquisition is continuous and every 5 seconds one set of 17 temperatures is read decoded to ASCII characters and sent to the host computer It is important to refer that the sensors don t have any syncronization clock for continuous acquisition and one acquisition is performed everytime the master send the order In this way the syncronising clock used is the microcontroller s crystal oscillator which is not very precise when c
5. 70 5meters radiusnetwork We ghtcabie 70 5meters Refer to Maxim application note AN148 11 guidelines for reliable 1 wire networks 4 3 7 2 Parasite Power Some slave devices like DS18B20 PAR don t need a local external power supply because they have an internal parasite power circuit to steal power from the 1 wire bus data line figure 4 16 When the data line is high the device is directly powered and one capacitor is charged when the data line is low power is provided by the charged capacitor Whenever the power from the bus and the capacitor aren t enough the master circuit must provide a strong pullup on the 1 wire bus figure 4 17 This situations always happens when the DS18B20 PAR is performing a temperature reading or is copying data to the EEPROM No other activity can take place on the 1 Wire bus while the strong pullup is enabled Refer to DS18B20 PAR datasheet for more details 9 4 3 8 Data packet The DS18B20 PAR s memory is organized as shown in figure 4 18 Each time a tem perature is measured the value is stored in bytes 0 LSB and 1 MSB and then the 32 CHAPTER 4 SYSTEM REFERENCE 64 BIT ROM 1 wire PORT ALARM LOW TRIGGER Tr REGISTER EEPROM CONFIGURATION REGISTER EEPROM DS18B20 PAR GND DQ Micro processor To Other 1 Wire Devices 1 Wire Bus Figure 4 17 DS18B20 whole scratchpad packet 9 bytes is sent to the master The rea
6. Q 82779 Hz Tia 28kH Z Individual noise values 1t1113 Ens Eee fo X In fonna mi ond 120 x 10 120 x In 222 28000 1 Emis 769 326nV Ignoring the 1 f noise En Eshitenoise mas fmin 120 x 4 28000 1 752 981nV The near results are because fmar fmin gt gt fne The 1 f noise may be ignored Intt1113 Iwhitenoise V fmax dein 10 x 10 54 28000 1 Luna 1 67329p A R1 Eum V4AKTRi fmax as Ton V A X 1 38 x 10728 x 25 273 x 10 x 108 x 28000 1 Em 67 865uV 50 APPENDIX C PRE AMPLIFIER ELECTRONICS CALCULUS R2 EnR2 V AKT Rol fmaz TH fmin 4x 138 x 10 28 x 25 273 x 1000 x 28000 T Enno 678 655nV R3 EnR3 V4KTR3 X Saas Dr Trai 4 x 1 38 x 1072 x 25 273 x 63400 x 28000 1 Ena 5 404uV Individual output noise values En outLT1113 E owns 1 8 Enua 1 SHO 769 326 x 107 49 54uV Er ou L T1113 Er outlt1113 1 amp x Ry X Innn 1 634100 x 10 x 106 x 1 67329 x 10712 E outit1113 1 0776mV En outR4 En oum 1 2 Enn 1 S889 67 865 x 1075 4 3705mV En out R2 Eaa E Enr op 678 655 x 107 43 034 V Essai Rs En outRs EnRs 5 404uV Output noise value C 4 NOISE En outt3 2 2 2 2 2 En out x Mu Gaga
7. 5 55 1 3994561 9 55 1 3990641 13 55 1 3986721 17 55 1 3982801 21 55 1 3978881 25 55 1 3974961 29 55 1 3971041 33 55 1 3967121 37 55 1 3963201 41 55 1 3959281 45 55 1 3955361 49 55 1 3951441 53 55 1 3947521 57 55 1 3943601 61 55 1 3939681 65 55 1 3935761 Table 4 2 hydrophone capacitance variations with depth e 3dB bandwidth between 100Hz and above 17kHz lowest noise as possible differential output output voltage range output between 5V and 5V 20 CHAPTER 4 SYSTEM REFERENCE e low input bias currents very important characteristic with capacitive transducers like the hydrophones to reduce offset voltages e smallest size as possible 4 2 2 1 Circuit overview The basic circuit is shown in figure 4 6 The design is based on a non inverting op amp based scheme which circuit is proposed for an hydrophone transducer in the datasheets of two low noise opamps LT1113 and AD743 Amplifier LT1113 is a low noise JFET opamp designed to amplify low level signals from high impedance capacitive transducers Following the amplifier is a differential output buffer amplifier SSM2142 to convert the single ended signal to a balanced output signal Capacitors C1 and C2 are used to eliminate DC signals and to set the amplifier s highpass cutoff frequency to 100Hz Two diodes D1 and D2 connected in anti parallel are used to protect the opamp s input from high voltages that may occur due to very strong signals re
8. 17 Each temperature value s size is constant and is composed with a signal char acter equal to 4 or plus 7 characters with the value in degrees centigrades plus one linebreak SXX XXXXNV If the temperature returned is equal to 28 000 V this means an error occured in the reading CRC codes are used to validade every temperature values received from the sensors BUSUINUSHORT CIRCUIT 21 characters This message is send if the 1 wire bus is in short circuit NOUDEVICESUINUTHEUBUS 22 characters 4 3 THERMISTOR CHAIN ELECTRONICS 29 This message is send if there are no devices in the bus or and most commonly if the array is not connected to the card e RESET ACQ ISR 14 characters This message is send after an error in the acquisition routine After the message is sent the microcontroler performs a reset Contact to the card s manufacturer or refer to section 4 3 12 e RESET OWRESETNV 14 characters This message is send after an error in the 1 wire reset routine After the message is sent the microcontroler performs a reset Contact to the card s manufacturer or refer to section 4 3 12 4 3 6 Thermistors The temperature sensors used in the array are the DS18B20 PAR manufactured by Maxim www maxim ic com Their specifications are e wire interface requires only 2 pins connection to work e derives power from data line parasite power
9. 17 19 Ri ue be Black 4 6 8 10 12 16 18 20 Figure 4 8 cables and connectors overview 24 CHAPTER 4 SYSTEM REFERENCE DS18B20PAR a Figure 4 9 thermistors cable and connector overview 4 2 3 4 Connectors 01 50 o o4 03 MSSJ CCP 5 Data I O Vi Not connected Not connected 1 DO 2 GN 3 NC 4 NC 5 NC Not connected p Table 4 6 thermistors 1 wire bus connector All array connectors are made by Impulse www impulse ent com A separate connector is used for the thermistors 1 wire bus The connector reference is MSSJ 5 Figure 4 9 and table 4 6 show the connectors pinout Hydrophone connections are made through two MHDL CCP 24 Figure 4 8 shows the array system cabling overview for the hydrophones and table 4 7 shows the hydrophone connectors pinout 42 HYDROPHONE ELECTRONICS MHDL CCP 24 Connectorl Connector2 1 GND Power 2 12V Power 3 Channel 1 4 Channel 1 5 Channel 3 6 Channel 3 7 Cha nnel 5 8 Channel 5 9 Channel 6 10 Channel 6 11 Channel 8 12 Channel 8 13 12V Power 14 12V Power 15 Channel 2 16 Channel 2 17 Channel 4 18 Channel 4 19 Channel 7 20 Channel 7 21 12V Power 22 23 24 1 GND Power 2 12V Power 3 Channel 9 4 Channel 9 5 Channel 11 6 Channel 11 7 Channel 13 8 Channel 13 9 Channel 14 10 Chann
10. 5 Serial Interface Messages The communication between the card and the computer host is performed through ASCII messages in simplex mode from the card to the host The messages semantics allow the user to read them directly using a serial port interface software such as Hyperterminal To make the development of the interface software easier for the host computer the number of possible messages is finite and each message lenght is constant Each message has a specific and constant number of characters being either al phanumeric or hexadecimal values The description of each message start and end with This characters are not sent by the card In the description spaces are shown as LJ Some messages include linebreaks Linebreaks are sent using 0x0A New Line fol lowed by 0x0D Carriage Return To distinguish this from the ASCII characters lets assume a linebreak to be like VN Message list 1 WIREUTHERMISTORSUARRAY 26 characters This message is sent everytime the card s microntroller is powered ON or a software reset is performed in the microcontroller This is always the first message sent by the card to the host TEMP 6 characters This message is the header for a set of 17 temperature values The 17 temper atures from the array thermistors are sent to the host after this message The first temperature to be sent is from thermistor 1 and ends with the temperature from thermistor
11. DS18B20 PAR EEPROM is not used According to the manufacturer 14 11 an R C filter must be used on With EPROM Programming 12V BV Regulator Vv VDD POL VPP UART 1 Wire Bus SIN RXD Eo d or uC DS2480 DS9503 SOUT TXD TXD GND DS9503 Return UN Y Figure 4 22 DS2480B circuit example networks longer than 1m and under 100m figure 4 23 In our application this filter is 4 3 THERMISTOR CHAIN ELECTRONICS 37 DS2480B 1 Wire Network IE 700pF Figure 4 23 R C filter helps DS2480B interfaces on short to medium networks bypassed and the network is still functioning ok To improve the 1 wire network reliability and performance 11 the DS2480B 1 wire timings and slew rates may be tunned to better match the network physical medium Manufacturer tests with long and short bus lines has shown that the optimum timings for all networks areas follows e Pulldown Slew Rate 1 37V us e Write One Low Time 11js e Data Sample Offset Recovery 10js These timings apply only to networks where the pullup voltage is between 4 5V and 5 5V 4 3 11 Electronic card The electronic circuit for the thermistors chain master card is shown in figure 4 24 As sembled on a pcb board with PC 104 dimensions the circuit includes the microcontroller PIC18F6620 unit plus the 1 wire bridge DS2480 One line driver receiver for RS 232 chip MAX203ECWP connects the microcontroller s
12. Ef outlt1113 FR gE En 2 E diis V 49 54 x 10 9 1 0776 x 10 3 4 3705 x 10 3 43 03 x 10 9 5 404 x 10 9 4 5019mV 51 Appendix D Pre amplifier electronic schematics and PCB This appendix presents the schematic the PCB components layout and the PCB layout for the hydrophone pre amplifier circuit The following pages are organized in the following order schematic PCB components layout PCB board layout and component order list D 1 Schematic C13 V o 5 7 IC3 MC78M08 1uF 100nF GND IN 100nF 100nF x C6 cs C10 L7908CV c1 C14 MI a 5 100nF 100nF 100nF lt Ed gt iL E N Out R2 R3 Il C ul 63k4 6 2 v OUT FORCE FOUT FORCE E 113CS8LMD OUT SENSE VIN GND OUT SENSE Lu o lo CIA OUT FORCE 5 a lB v Q 5026 A a DRIVER Sr p Bn Y SSM21428 E N o T a a a z2 z z o o o Ed lt lt Figure D 1 Hydrophone pre amplifier 52 D 2 PCB AND COMPONENTS LAYOUT D 2 PCB and components layout 22 11 2006 18 15 49 C development eagle siplab projects Array2 Preamp final 4laye Figure D 2 pre amplifier top components placement 53 54 APPENDIX D PRE AMPLIFIER ELECTRONIC SCHEMATICS AND PCB 22 11 2006 18 16 34 mirrored C development eagle siplab projects Array2 Preamp Figure D 3 pre amplifier bottom components placement D 3 PCB LAYOUT D 3 PCB layout 22 11 2006 18 17 11 mirrored C development eagle si
13. I _ Pre amp Pre amp Figure 4 7 power supply cable Number of cores 3 Cross section 1 5 mm Nominal Voltage 450 750 V rms Nominal current 22 A 2 RS code 4099486 Table 4 4 power supply cable properties 4 2 3 2 Signal cable The electrical signals from the hydrophones pre amplifier modules are connected to the surface buoy via a twisted pair cooper cable see figure 4 8 Table 4 5 show the cable s properties Number of cores Inner conductor 2 10 x 0 254 mm 20 AWG Insulation 1 92 mm diameter PVC Twists Left hand lay 17 24 twists m External diameter 5 12 0 20 mm Capacitance 77 pF m Resistance 340 km Maximum current 8 A RS code 0360958 Table 4 5 signal cable properties 4 2 3 3 l wire cable The 1 wire bus uses a twisted pair cable equal to the signal cables Figure 4 9 shows the connections between the 1 wire bus cable the top connector and the temperature sensors 42 HYDROPHONE ELECTRONICS 23 Connector ctor 1 Signal 3 4 16 17 5 6 118 7 8 9 10 19 20 1 17 1 12 W V WV WM Connec U or 1 Signal 3 4 16 17 5 6 17 18 7 8 9 10 19 20 11 12 IRR PODERE PETTO TTT A A A Ds EEN Do PF A PA gt A O O E Cable color code Connector Pinout 12V Yellow Green 2 14 GND Brown 1 12V Blue 13 21 Signal Outt Red 3 5 7 9 11 15
14. R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 Q1 CPOL EUB 3528 21W C10 C11 C8 C9 R1 C1 C2 C3 CA C5 C6 C12 C7 POWER SUPPLY IN 1WIRE IC RS232 IC USI Figure E 23 component order list for thermistors master card Appendix F Manufacturers and Suppliers Parts Suppliers Contacts Electronic com RS amidata www rsportugal com ponents Hydrophones Sensortech http www sensortech ca http www impulse Impulse Connec Impulse ent cort home biil tors Analog devices Avnet Silica www rsportugal com components www maxim ic com prototype orders use the excel sheet to perform any order the on line re Maxim compo Maxim quest on the site doesn t nens work the credic card val idation always give er rors Inox parts MGLInox Conceig o de Faro Shackles thim bles Polyamid mesh AUTEC www autec vertrieb de strenght memo Slesia Nautical equipment store in Olh o ber cable Table F 1 list of equipment and parts suppliers 74 Appendix G Hydrophone case mechanical specifications Figures G 1 and G 2 respectively show the mechanical design of the hydrophone case and the case support for attachment to the strenghtmember rope Uu Ta Date Array16 SIPLAB hannar Figure G 1 hydrophone case mechanical design design 75 76 APPENDIX G HYDROPHONE CASE MECHANICAL SPECIFICATIONS Tae der
15. does not need a local power supply e multi drop capability simplifies distributed temperature sensing applications e requires no external components e 0 5 C accuracy from 10 C to 85 C e measures temperatures from 55 C to 100 C 67 F to 212 F e thermometer resolution is user selectable from 9 to 12 bits e converts temperature to 12 bit digital word in 750 ms max e ideal for use in remote sensing applications e g temperature probes that do not have a local power source and the thermistor s pinout is shown in figure 4 12 Thermistor s typical error curve is given in figure 4 13 that mainly shows that these T sensors have a bias of 0 2 C and a 3 standard deviation error less than 0 3 C Refer to sensor datasheet 9 for further details DEAR GND 1 Ground Lu DO 2 Data In Out NC 3 Not Connected BOTTOM VIEW TO 92 DS18B20 PAR Figure 4 12 Thermistors pinout 30 CHAPTER 4 SYSTEM REFERENCE L 30 Error gt Thermometer Error C eo I O k a a SS See n Reference Temp C Figure 4 13 DS18B20 PAR typical error curve 4 3 7 1 Wire bus The 1 wire bus is a digital serial data communication bus featuring low speed data low signaling low power low cost 1 wire data and 1 ground lines and power over data line More details info about 1 wire are available in reference 10 4 3 7 1 Serial network The 1 wire bus may work as a seria
16. necessary apply silicone based grease 10 there are three electrical connectors to be attached to the surface buoy two large 24 pin connectors one for each 8 hydrophone sub array and one smaller 5 pin connector for the digital thermistor sensor array The two large connectors are marked H1 and H2 for the upper half and lower half arrays respectively They should attached to the respectively marked H1 and H2 receptacles on the buoy s top cover The 5 pin smaller connector should be attached to the respective receptacle on the buoys cover The user should ensure that the digital thermistor master card is correctly installed inside surface buoy see 4 3 for details Don t forget to pass the array cable inside the buoy s float 3 3 2 Software Please refer to the AOB2 manual 1 for data acquisition software initialization and prepar ing testing before deployment This section will concentrates on the instalation of the thermistor chain software which is a new piece of hardware not previously described The instalation of the thermistor chain software is done by placing the file Thermistor ChainDigital py in the AOB programs directory from where it will be activated as an aditional service to be run on system startup see section 4 3 12 2 for more de tails on this file format Configuration of the software can be achieved by editing the ThermistorChainDigital py in any text editor variables to change if any are the serial port dev ttyS1 f
17. read Figure E 15 OWREADBYTE subroutine 68 APPENDIX E THERMISTOR MASTER CARD TECHNICAL DETAILS DS2480 STRONG PULLUP ON Set strong pullup ON Send OxEF to the DS2480B Flush the uart input buffer Figure E 16 DS2480 STRONG PULLUP ON subroutine flowchart DS2480 STRONG PULLUP OFF Set strong pullup OFF Send OxDF to the DS2480B Flush the uart input buffer END return Figure E 17 DS2480_ STRONG PULLUP OFF subroutine flowchart DS2480 TERMINATE Terminate strong pullup before timeout Send 0xF1 to the DS2480B Flush the uart input buffer Figure E 18 DS2480_ TERMINATE subroutine flowchart E 3 Thermistors master PCB This appendix presents the PCB components layout and the PCB layout for the thermis tors master circuit The schematic for this card is on 4 24 E 3 THERMISTORS MASTER PCB E 3 1 Pcb and components layout PC 104 Standard base Dz Be De cd 8 ED ON ERROR LED K LED o L DEVICE R7 D R6 bl o ERASE 1 POWER SUPPLY IN 6 PIC18F6622 RS232 ORT 6 23 05 2006 12 26 25 C development eagle siplab projects AOB2 Thermistor_chain thermistor_master brd Figure E 19 thermistors master top components placement not to scale 70 APPENDIX E THERMISTOR MASTER CARD TECHNICAL DETAILS o o o C o O o 0000000 O
18. 2 hydrophone case support mechanical design 76 Abstract This report contains the user guide and the system reference for the analog 16 hydrophone AOB vertical line array The array is a 67 5m long cable with 16 4m spaced hydrophones and 17 digital thermistor sensors distributed along its length Each module has a ded icated preamplifier to increase signal strenght at the hydrophone output and drive a balanced line to transmit the signal to the surface buoy s electronics The thermistor sensors are digital devices that transmit the temperatures values through a 1 wire digital serial bus This report presents the system user guide and the system reference guide The user guide has instructions for system deployment everyday usage and maintenance The system reference guide is intended for specialized technicians for system repairing and or upgrade Chapter 1 Introduction Following the requirements of CIN TAL projects for underwater acoustic research there was the need for an acoustically dense array with however nearly the same acoustic aperture than the previous 8 hydrophone vertical array of the AOB1 system 2 Therefore the most important improvement is the increase of the number of hydrophones and also the array geometry that is should be equispaced at 4 m so as to allow for easy beamforming for surface noise studies and time reversal as required by UAB Underwater Acoustic Barriers project The other requirement is t
19. 65536 to 0 Wait 1 second ON LED ON Acquisition LED OFF Error LED OFF Figure E 2 Power ON 59 60 APPENDIX E THERMISTOR MASTER CARD TECHNICAL DETAILS Timer0 0 Enter interrupt service routine HIGH_ISR gt TMRO_ISR Timer_counter counter 0 ON LED ON Call ACQ_ISR Acquisition LED OFF Routine to acquire the temperatures and Error LED OFF send the values to the host computer Timer0 49152 Figure E 3 Timer0 interrupt E 2 PIC18F6620 SOFTWARE FLOWCHARTS 61 ACQ ISR Reset error counter Error timeout 0 Acquisition LED ON Call DS2480 COMMAND MODE Call OWRESET Send a reset to the 1 wire bus to synchronise all the slaves and get the bus status Call DS2480 DATA MODE Skip ROM All devices will start the temperature acquisition simultaneously Send 0xCC to the DS2480B Read return value N Value 0xCC v Cali DS2460_COMMAND_MODE_ _ call os2400 STRONG PULLUP_ON LS fermin puse terminate pulse can 552480 DATA Moe Convert temperature Send 0x44 to the DS2480B Read return value N Value 0x44 v TS COMMAND MODE T can 552480 STRONG FULLUR OFF TT remmmarE Lest owneser Figure E 4 Acquisition routine flowchart 1 of 4 62 APPENDIX E THERMISTOR MASTER CARD TECHNICAL DETAILS Thermistor counterz17 exi ow eser T TS DATA MODE Match ROM Select one device Send 0x55 to D
20. 8kHz Storage and operating temperature 30 C to 60 C Pre Amplifier Gain 36dB continued on next page 43 44 APPENDIX A TECHNICAL SPECIFICATIONS 3dB Bandwidth 108 27Hz up to 52 796kHz Output voltage range referenced to ground 5V Differential preamp output voltage range 10V Table A 1 analog 16 hydrophone and temperature sen sor array technical specifications Appendix B Equipment checklist Array 3 x Top connectors spare o rings 3 x Dummies for the impulse connectors 1 x Shackle to connect the array to the buoy 1 x Shackle to connect the array to the bottom weights 1 x Lead weights plus holding band 8kg 1 x Isolation tape 1 x Plastic cable ties plier AOB2 1 x Thermistors master electronic card Table B 1 equipment checklist 45 Appendix C Pre amplifier electronics calculus R3 C2 A N SAG ND V OUT FORCE OUT SENSE VIN GND OUT SENSE OUT FORCE V PHONE1 N FDLL300 SO26 DRIVER SSM2142S D2 D1 VI FDLL300 HYDRO AGND Figure C 1 Pre amplifier circuit C 1 Output voltage range Power supply voltage 9 3V lt Vs w lt 35V Voltage Regulators Vs 8V LT 1113 output voltage range Vg t8V gt VRange 1t1113 6 8V SSM2142 output voltage range referenced to ground VRange ssm2142 5V 0 1 distortion Outpu
21. CINTAL Centro de Investigacao Tecnol gica do Algarve Universidade do Algarve Analog 16 hydrophone vertical line array for the Acoustic Oceanographic buoy AOB F Zabel C Martins and A Silva Rep 03 06 SIPLAB 18 August 2006 University of Algarve tel 351 289864258 Campus de Gambelas fax 351 289864258 8005 139 Faro cintalQualg pt Portugal www ualg pt cintal Work requested by CINTAL Universidade do Algarve Campus de Gambelas 8005 139 Faro Portugal tel 351 289800131 cintal ualg pt www ualg pt cintal Laboratory performing the work Signal Processing Laboratory SiPLAB Universidade do Algarve Campus de Gambelas 8000 117 Faro Portugal tel 351 289800949 Projects RADAR FCT contract POCTI CTA 47719 2002 UAB FCT contract POCI MAR 59008 2004 Title Analog 16 hydrophone vertical line array for AOB2 Authors F Zabel C Martins and A Silva Date August 18 2006 Reference 03 06 SIPLAB Number of pages 77 seventy seven Abstract This report describes the sensor array system designed for the Acoustic Oacenographic Buoy version 2 AOB2 and is intended as a user and maintenance manual and system reference Clearance level SiPLAB CINTAL eyes only Distribution list SiPLAB 2 2CD CINTAL 1 1CD Total number of copies 3 three Copyright Cintal 2006 Approved for publication CA E Alte da Veiga President Administration Board
22. ETECT Call D82480 POWER ON RESET simulate a power on reset on the DS2480B Call DS2480 SET TIMING send a reset pulse to the 1 wire to synchronize the bus Configure DS2480 1 wire timings and slew rates Set PDSRC 1 37V us Send 0x17 to the DS2480B Call DS2480 SEND DATA Received 0x16 Set W1LD 10us Send 0x45 to the DS2480B Call DS2480_SEND_DATA Received 0x44 7 Set DSO WORT 8us Send 0x5B to the DS2480B Call DS2480_SEND_DATA Received 0x5A Set pullup duration 1048ms Send 0x3B to the DS2480B Call DS2480_SEND_DATA Received 0x3A Read RBR baud rate Send 0x0F to the DS2480B Call DS2480 SEND DATA Received 0x00 Send one test bit to the 1 wire bus Send 0x95 to the DS2480B Call DS2480 SEND DATA Received 0x97 Y Call DS2480 COMMAND MODE Change the communication with the DS2480B to command mode Figure E 8 DS2480B_ DETECT subroutine E 2 PIC18F6620 SOFTWARE FLOWCHARTS 65 DS2480 POWER ON RESET Change PIC s uart n 1 baud rate to 2400 bauds Send 0x00 to reset the DS2480B Restore PIC s uart n 1 baud rate to 9600 bauds Flush the uart input buffer Figure E 9 D82480B POWER ON RESET subroutine DS2480 SET TIMING Flush the uart input buffer Send a reset pulse to the 1 wire bus Send 0xC1 Flush the uart input buffer Figure E 10 DS2480B SET TIMING subroutine DS2480 DATA MODE Set data mode comm
23. KE E Array16 SIPLAB hydrophone_case Figure G 2 hydrophone case support mechanical design Bibliography 1 2 ut co O N o 10 11 12 13 14 15 16 Zabel F Martins C Silva A Acoustic Oceanographic Buoy v2 AOB version 2 SiPLAB University of Algarve November 2005 Jesus S M Farinha L Martins C Silva A J Soares C Acoustic Oceanographic Buoy System Description and Operation AOB version 1 SIPLAB University of Algarve December 2004 SEDRA Adel SMITH Kenneth Microelectronics Circuits fifth edition Oxford Uni versity Press 2004 MANCINI Ron Op Amps for Everyone Design Reference Texas Instruments 2002 MOTCHENBACHER C D CONNELLY J A Low Noise Electronic System De sign Wiley interscience publications 1993 LT1113 datasheet rev B 1993 www linear com 2006 AD743 datasheet rev E 2003 www analogdevices com 2006 SSM2142 datasheet rev B www analogdevices com 2006 DS18B20 PAR datasheet www maxim ic com 2006 l wire overview www maxim ic com 2006 AN148 Guidelines for Reliable 1 Wire Networks www maxim ic com 2006 AN27 Understanding and Using Cyclic Redundancy Checks www maxim ic com 2006 PIC18F6620 datasheet www microchip com 2006 DS2480B datasheet www maxim ic com 2006 AN155 1 Wire Software Resource Guide www maxim ic com 2006 app192 Using the DS2480B Serial 1 Wire Line Driver www maxim ic com 2006 TT
24. S2480B Send device 64 bits code address LSB first Read return values Returned values ok M Read device scratchpad 3 Send OxBE to DS2480B Read return values Value 0xBE returns byte 0 gt temperature LSB temet tempere se returns byte 1 gt temperature MSB Do comme gt To cmomemsme J Do comem 1 Do cwowmane gt To cmow mme 1 Do comem IMP P SUMI returns byte 8 gt CRC code T cancweck SeRATGWPAD ONC ere ok Modify the readed temperature value to na error default value 28 C Save temperature in a temporary memory Thermistor counter i Call OWREADBYTE g Counter 0 Y Call OWRESET Figure E 5 Acquisition routine flowchart 2 of 4 E 2 PIC18F6620 SOFTWARE FLOWCHARTS 63 Send string TEMP to host computer Thermistor counterz17 g Call SEND_TEMP_TO_PC fi Thermistor_counter Counter 0 Y ON LED ON Acquisition LED OFF Error LED OFF Timer_counter Timer0 49152 1 END Return from interrupt Figure E 6 Acquisition routine flowchart 3 of 4 Send message BUS IN SHORT CIRCUIT to the Error Increment error counter Error timeouttt Send message NO DEVICES IN THE BUS to the host host Wait 1 second Reset the microcontroller by software Figure E 7 Acquisition routine flowchart 4 of 4 64 APPENDIX E THERMISTOR MASTER CARD TECHNICAL DETAILS DS2480B D
25. able e any other problem in the cable generates error messages and a T sensor reading of 0 degrees inside the buoy the error LED is on In general these problems can not be simply solved see section 4 3 If the problem does not fit in any of the above please contact Siplab CINTAL for further assistance Chapter 4 System Reference This chapter describes the array hardware in a higher technical detail This information should be used by a qualified techician so as to ensure the minimum knowledge for testing or repairing electrical or mechanical components This chapter is organized as follows the first section addresses the array mechanical parts the second section describes the hydrophone electronics and connections and the third and last section gives a tutorial description of the thermistor sensor electonics and respective master card 4 1 Mechanical The array mechanics includes all the elements used to keep the array structure intact and protect the electrical and electronic parts All these elements are represented in figure 4 1 4 1 1 Protection Sleeve A polyamid sleeve is used to protect and to keep the wires and cables together The sleeve is made of resistant and flexible polyamid mesh The result is a compact flexible and robust cable The sleeve is manufactured by AUTEC www autec vertrieb de and the used references are GS 12 GS 15 GS 20 and GS 25 AUFLEX 4 1 2 Top Thimble Top ring to connect the array to
26. ceived by the hydrophone 100nF 12V x CB 100nF 100nF gt Jos 1uF C6 C8 E 100nF 100nF gt i ef AGND 1 47uF R2 R3 i a 63k4 z 9 V OUT FORCE OUT SENSE VIN 4 GND OUT SENSE OUT FORCE ve OUT SQ26 DRIVER SSM21428 YDROPHONE1 _ AGND Figure 4 6 pre amplifier circuit 4 2 2 2 Output Voltage Range The output voltage range of the amplifier is limited by the power supply of the electronics Using 8V voltage regulators the output voltage range of the pre amplifier is 5V lt Vout lt 5V reference to ground while the differential pre amp output voltage range is 10V lt V44 10V See detailed calculus in appendix C 1 42 HYDROPHONE ELECTRONICS 21 4 2 2 3 Pre amplifier gain Detailed gain calculus can be found in appendix C 2 while a short table with a few important theoretical gain values are shown in table 4 3 Note the maximum gain in the frequency band of 36 dB and a highpass cutoff frequency of 108 Hz f Ars Dose mig Hz dB 0 0 00 0 16 0 992 69 5 108 27 45 6 33 17 108 3 52800 1 R3 R 64 4 36 2 52800 45 6 33 17 00 0 00 Table 4 3 theoretical hydrophone pre amplifier gain 4 2 2 4 Pre amplifier bandwidth Pre amplifier bandwidth varies with opamp characteristics and component temperature dependence Detailed bandwidth calculus are shown in appendix C 3 and main results reported belo
27. d array connectors 7 remove the top shackle 8 leave the ballast weights attached unless it cause problems to the transport or storage 9 let the array dry 10 store it in the AOB2 box over the buoy 3 5 Maintenance Due to its characteristics the array requires very few maintenance and a minimum checkup before any deployment is sufficient Follow these steps e check if the o rings are very dry or damaged before every experiment or deployment If so replace them e check for any corrosion on every metallic parts connectors shackles every 4 months and before every deployment e check the protection sleeve for cuts before each deployment e check the straps that hold the ballast before every deployment e check if the electrical cables are dry to cause breaches when bent every 4 months If so replace them Always wash the array with fresh water after recovery to remove the salt water and let it dry on air preferably protected from direct sun light 14 CHAPTER 3 USER MANUAL 3 6 Troubleshooting This section describes possible problems that may occur with the array and their solutions The only problems that can be found directly in the array are mechanical since all electrical problems are only detected when the array is connected to the buoy and for this ones both array and buoy must be checked The buoy is very unstable at the sea e Increase the ballast weight The protection s
28. data 0 data 1 data 2 data 3 data 4 data 5 data 6 data 7 data 8 data 9 data 10 data 11 data 12 data 13 data 14 data 15 data 16 print dataline FILE writelines dataline FILE writelines n FILE flush ser close FILE close Table 4 12 source code for reading thermistor chain data Appendix A Technical specifications Name Array16 Description Underwater vertical array designed for the AOB2 buoys with 16 hydrophones Sensors Hydrophones 16 Thermistors 17 Sensor locations Hydrophones Distance from the top thimble to the first hydrophone 5 55m Distance between hydrophones 4m Distance from the top thimble to the last hydrophone 65 55m Thermistors Distance from the top thimble to the first thermistor 5 55m Distance between thermistor 4m oDistance from the top thimble to the last two thermistors 65 55m Mechanics Dimensions and Weight Total Length 67 5m Estimated weight in air excl ballast 50 kg Estimated weight in water excl ballast 12 kg Ballast s weight 8 kg Top thimble inside diameter 14mm Bottom thimble inside diameter 14mm Strength member made of Dyneema Strength member diameter 6mm Strength member breaking load 1500 kg Protection sleeve mesh made of Polyamid Hydrophones pre amp Outside Case oDiameter 33 4mm oLength 129mm Hydrophone Reference Q26 from Sensortech Frequency response flat from 1Hz to 2
29. e for the master to send 4 3 THERMISTOR CHAIN ELECTRONICS 31 Master ADA ADO Figure 4 15 1 wire bus linear topology commands or data to one specific device or to several devices at the same time point to point or point multipoint On the slaves side they can only send data to the master one at the time point to point and after request from the master In the 1 wire network two terms are used to describe measurements radius and weight The radius of a network is the wire run distance from the master end to the furthest slave device in meters The weight of a network is the total amount of connected wire in the network in meters To assure a realiable network the radius must not be greater than 750m due to protocol timings and the weight is limited to 200m or 500m due to signal attenutation 200m when using a single pull up resistor and 500m when using active pullups to provide higher currents under logic control The weight of a network is not only specified by the cable lenght but also by the slave devices and pcb boards e i buttons slave devices 1 meter per device e non i buttons slave devices DS18B20 PAR 0 5 meters per device e pcb trace with 24pF 1m In this array the weight and radius of the network is wel9ht staves 17devices x 0 5 8 5meters weighteabie array length cable length from the array to the master 65 55m 2 5m 68 05m TOmeters weightnetwork Weightsiaves Weighteabie 8 5m 70m
30. ed leads 193 5 1 0dBV re 1 Pa 20 C 20 V bar 24 nC bar 1 4nF 10 20 C lt 1dB loss from 0 C to 35 C 0 33 increase per C 7 loss per 1000m 1000m flat from 1Hz to 28kHz lt 0 2mbar g when properly mounted 30 C to 60 C 25 4mm 25 4mm 16 grams two red and black stranded 28AWG 15cm long Hytrel insulated leads gt 500 MQ yes Table 4 1 SQ26 Sensor Technology Ltd hydrophone specifications 4 2 2 Pre amplifiers The pre amplifiers were designed to adapt the small electrical signals obtained from the variation of the hydrophone s capacitance to the input voltage range of the acquisition electronics inputs ADCs inputs taking into account the attenuation of the transmission line As a starting point for the design of the circuit the main goals are e approximate voltage gain of 36dB 1ADC Analog to Digital Converter 42 HYDROPHONE ELECTRONICS Sensitivity versus Frequency Sensor Technology SQ26 Broadside End fire 180 00 181 00 182 00 183 00 184 00 185 00 186 00 187 00 188 00 189 00 190 00 191 00 192 00 193 00 194 00 195 00 196 00 197 00 198 00 199 00 200 00 0 1 2 3 4 5 6 7 8 9 101112131415 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 Frequency kHz Sensitivity dB ref 1V mPa Figure 4 5 S026 Sensitivity versus frequency Depth m Capacitance nF
31. el 14 11 Channel 16 12 Channel 16 13 12V Power 14 12V Power 15 Channel 10 16 Channel 10 17 Channel 12 18 Channel 12 19 Channel 15 20 Channel 15 21 12V Power 22 23 24 Table 4 7 hydrophone connectors 25 26 CHAPTER 4 SYSTEM REFERENCE 4 3 Thermistor chain electronics The digital thermistor chain is a newly developed system that is composed of a thermistor sensor array and a master board The sensor array is composed of a single cable with two wires that is connected to the master board The master board communicates with a computer CPU via a standard RS 232 port The digital thermistor array can be used integrated in the acoustic array or standalone future version 4 3 1 Overview and setup The thermistor chain is formed of a 2 wire cable with 17 molded T sensors and the electronic Thermistor s Chain Master board This card has an input for the 2 wires from the array and a serial RS232 output as shown on figure 4 10 After the card is o ppuese o r gt 1 ON LED Red 2 Acquisition LED Green 3 Error LED Red SIPLAB 2006 O THERMISTORS CHAIN MASTER A Power supply connector B PIC programmer PGC PGD or SE ono C 1 wire connector D 1pps input not used E rs232 port 2 RX Host computer 3 TX Host computer 5 GND Figure 4 10 thermistors master card powered ON it starts reading the temperat
32. emory is INPUT CO O D OT T d LSB Figure 4 20 DOW CRC generator available in the master one better and faster way to check the DOW CRC is to use a look up table that is accessed directly for any 8 bit value currently stored in the CRC register and any 8 bit pattern of new data For the simple case where the current value of the CRC register is 00 Hex the 256 different bit combinations for the input byte can be evaluated and stored in a matrix where the index to the matrix is equal to the value of the input byte i e the index will be I 0 255 It can be shown that if the current value of the CRC register is not 00 Hex then for any current CRC value and any input byte the lookup table values would be the same as for the simplified case but the computation of the index into the table would take the form of New CRC Table I for I 0 to 255 where I Current CRC EXOR Input byte Table 4 10 shows the lookup table values for the DOW CRC and table 4 11 shows an example about how to use it The look up table method is the one used in our system Refer to Maxim application note AN27 12 Understanding and Using Cyclic Redundancy Checks 4 3 10 1 Wire Bus Master The system master is composed by a microcontroller PIC18F6620 13 and a serial to 1 wire interface chip DS2480B 14 The microcontroller is responsible for e set the temperature acquisiton rate to aproximately 5seconds e communica
33. h dimensions a and complete system drawing b Chapter 3 User Manual 3 1 Introduction The first thing the user must notice is that the array is not a standalone element it is part of the AOB2 system and therefore all the information shown in this manual should not be used alone but always as a complement to the AOB2 report manual This chapter details the high level operations regarding the correct use and mainte nance of the array plus some troubleshooting hints The next chapter introduces the user to the hardware details about the array The following two sections present the pre deployment the recover and post deployment procedures The fourth section enu merates some maintenance recommendations The last section gives some hints to solve possible problems that may happen with this device while being used at sea or during maintenance preparation for sea trial 3 2 Hardware overview This section describes the few hardware parts that compose the array e the main cable composed by the electrical wires sensors and one strength member all protected by polyamid mesh sleeve e hydrophone cases to protect the hydrophone and the pre amplifier electronics inside a polyurethane mold e thermistor s inside a polyurethane mold e a Dynema based strength member to maintain the vertical structure of the array and to attach the sensors so that they are held always at the constant distance e top thimble fasten to the top
34. hat the new array system should be interconnected with the AOB2 surface buoy therefore the same bandwidth and connector pinout The array mechanical design should be improved so as to offer a better compact and streamed line of cables for easy handle during deploying and recovering operations Another requirement is that each hydrophone module should also contain a temperature sensor for online reading The handling of the temperature data stream should be as light as possible in terms of cabling The result is a new array that follows a very similar design to that of the older AOB1 model with however several improvements i a more compact mechanical design includ ing a polyester sleeve covering the cables along the array ii a new proprietary preamplifier design and 3 a new digital temeprature sensor bus system with T sensors colocated with the hydrophones The following sections will describe the array from a basic user perspective up to a more detailed description The next section starts with an overall description Following is the user manual The third section covers all the array design details Chapter 2 Overall Description The analog array is a 67 5m long cable with 16 4m spaced hydrophones and 164 1 hy drophone colocated digital thermistor sensors distributed along its length figure 2 1 Each module has a dedicated preamplifier to enhance the signal and drive one balanced Hydrophones Connectors
35. he most significant byte The scratchpad CRC is calculated from the data stored in the scratchpad and therefore it changes when the data in the scratchpad changes The CRCs provide the bus master with a method of data validation when data is read from the DS18B20 PAR The Dallas Semiconductor 1 Wire CRC DOW CRC magnitude is 8 bits and is capable of detect the following types of errors e Any odd number of errors e All double bit errors 34 CHAPTER 4 SYSTEM REFERENCE e Any cluster of errors that can be contained within an 8 bit window 1 8 bits incorrect e Most larger clusters of errors The equivalent polynomial function of the DOW CRC is CRC X8 X5 XA 1 The bus master can re calculate the CRC and compare it to the CRC values from the DS18B20 PAR using the polynomial generator shown in figure 4 20 This circuit consists of a shift register and XOR gates and the shift register bits are initialized to 0 Starting with the least significant bit of the ROM code or the least significant bit of byte 0 in the scratchpad one bit at a time should shifted into the shift register After shifting in the 56th bit from the ROM or the most significant bit of byte 7 from the scratchpad the polynomial generator will contain the re calculated CRC Next the 8 bit ROM code or scratchpad CRC from the DS18B20 PAR must be shifted into the circuit At this point if the re calculated CRC was correct the shift register will contain all 0s If m
36. icard Laici E TEE UR TTE here GP ake di a 4 3 12 Thermistor reading software riva alii Du I a AG Array systemi testing do e So ote es eli IV A Technical specifications Equipment checklist Pre amplifier electronics calculus C 1 Output voltage range a acc sa o wee vasi toe a C 2 Pre amplifier gain sl ao si basi ee dw dy Cio Bandwidth ste A Boas SS C I deo s iiu RP Pre amplifier electronic schematics and PCB Dik SehematiC Ta a te A us we YD ave a D 2 PCB and components layout B3 POB NOU g da ds ade ad a ed D 4 Component order list for pre amplifier board Thermistor master card technical details E 1 DS18B20 PAR addresses E 2 PIC18F6620 software flowcharts E 3 Thermistors master PCB pus ar Yea i ER WR E 3 1 Pcb and components layout IE Ed Mr gt 868 lla hae AA E 4 Component order list for thermistor master card Manufacturers and Suppliers G Hydrophone case mechanical specifications CONTENTS 43 List of Figures AOB2 analog array with dimensions AOB2 system overview analog array with dimensions a and complete system dfawing B eu utis qoe Bind g etc as ke deg Lea Ted Mechanical Overview cu ras ine de eo ee tee Sir Ig Ballast pi e mA xb ese eae ed mda dd hydrophone pre amplifier case mechanical overview SEL al pta eue aede fans Beat A a Doe oo ead 95026 Sensitivity versus frequency llle
37. ics from the water A spacer element is used to help tighten the case to the strength member Figure 4 3 shows a self explaining illustration 3D drawings can be found in appendix G Signal Hydrophone case filled with polyurethane Figure 4 3 hydrophone pre amplifier case mechanical overview 4 2 Hydrophone electronics 4 2 1 Hydrophones The hydrophones in use are the SQ26 figure 4 4 manufactured by Sensor Technology Limited http www sensortech ca main html whose main specifications are shown in table 4 1 Refer to figure 4 5 for a graph of the hydrophone sensitivity versus frequency Hydrophone capacitance variations may be calculated as follows Csozs 14NF 10 2000 gt 13269F lt Csga lt 1 54nF Csq26 d Cso 1 0 075 1 4nF 1 0 07 1000 1000 where d is hydrophone depth in meter These variations are shown in table 4 2 The relation between voltage and water pressure is g 24 nC bar A 24nC bar AV amp g TCI 17 1429 V bar 18 CHAPTER 4 SYSTEM REFERENCE Figure 4 4 SQ26 foto Voltage Sensitivity Charge sensitivity Capacitance Sensitivity variation with temperature Capacitance variation with temperature Capacitance variation with depth Operating depth Frequency response Acceleration sensitivity Storage and operating temperature Diameter Length Mass Electrical leads Electrical insulation Water block
38. it 12 bit 11 bit 10 bit 9 bit 8 MS Byte S S S S S 26 2 2 Figure 4 19 DS18B20 PAR temperature registers format TEMPERATURE DIGITAL OUTPUT Binary DIGITAL OUTPUT Hex 85 C 0000 0101 0101 0000 0550h 25 0625 C 0000 0001 1001 0001 0191h 10 125 C 0000 0000 1010 0010 00A2h 0 5 C 0000 0000 0000 1000 0008h 0 C 0000 0000 0000 0000 0000h 0 5 C 1111 1111 1111 1000 FFF8h 10 125 C 1111 1111 0101 1110 FF5Eh 25 0625 C 1111 1110 0110 1111 FE6Fh 55 C 1111 1100 1001 0000 FC90h Table 4 8 temperature conversion table default resolution is 12bits Resolution also limits the acquisition time the higher the resolution more time is needed to perform an acquisition table 4 9 Luckly the 1 wire protocol allows the master to issue a temperature acquisition to the all the slaves at the same time Nevertheless after the acquisition ends the master have to read each device temperature register full scratchpad one by one Resolution Max Conversion Time 9 bit 93 75 ms 10 bit 187 5 ms 11 bit 375 ms 12 bit 750 ms Table 4 9 Temperature acquisition time This system resolution is 12 bits Refer to DS18B20 PAR datasheet for more details 9 4 3 9 CRC Both DS18B20 PAR 64 bit identification code and scratchpad includes a CRC Cyclic Redudancy Check code for errors detection The identification ROM code s CRC is calculated from the first 56 bits of the code and is contained in t
39. l network with one master device and one or more slaves The master is a controller unit directly connected to the bus or through an interface chip The slave devices include temperature sensors memories mixed signal and secure authentication chips The seventen DS18B20 PAR are the slave devices in the array Each 1 wire slave device have a unique 64 bits identification codes stored in ROM and recorded from factory The code includes a 8 bits CRC validation code a 48 bits serial number and a 8 bits family number 28h DS18B20 PAR s family devices as shown in figure 4 14 This code is used as an address to access each device individually At appendix E 1 is a list with address from all the sensors in the array and the spares The number 8 BIT CRC 48 BIT SERIAL NUMBER 8 BIT FAMILY CODE 28h MSB LSB MSB LSB MSB LSB Figure 4 14 64 bits lasered rom code of lines needed for the 1 wire bus are only two a single data line and a ground line Three different network topologies are proposed by the manufacturer Linear Stubbed and Star This array uses the Linear topology figure 4 15 the 1 wire bus is a single pair starting at the master and extending to the farthest slave device Other slave devices are attached to the pair along its length without significant 73m branches or stubs The communication in the bus is always between one master and one or more slaves and the slaves can t communicate between them There is possibl
40. leeve is damaged e f it is not possible to replace at that moment use some pvc tape to cover the area The shackle s bolts are too tight e Remove the plastic tie e Use some lubricant like WD40 to remove the bolt e If the shackle shows any oxidation replace it One connector has residues of water inside e Remove the o ring from the connector using a thin plastic tie usually helps and check if it is damaged Replace if necessary e If the o ring is ok the problem may be lack of silicone based grease on the o ring or the connector wasn t tight enough The signals in one or more channels are not the expected Look at the troubleshooting section in the AOB2 manual Check the connectors to see if they are loose or if there is water inside and make a test stroke each hydrophone and check the result Apply some contact cleaner Check the buoy s electronics and software A value of 28 or 0 degrees appear in the T sensor reading e a value of 28 denotes a reading error on the temperature sensor It should be very unusual and may appear once in a while If this reading becomes persistent in time then a T sensor may have a permanent problem and should be replaced If this reading appears in a number of sensors say a full section it may mean that the bus is in open circuit between that section and the main master card The solution is to replace the faulty portion of c
41. o DDd o e o o J o o o o o 22pF22pF o 8 o o os 2 o o 69 6 3o o o 9 o o o O 25 ae o o o o o o Mm iwi V 23 05 2006 12 27 20 mirrored C development eagle siplab projects AOB2 Thermistor_chain thermistor_master brd Figure E 20 thermistors master bottom components placement not to scale E 3 THERMISTORS MASTER PCB E 3 2 Pcb layout 388 gA JdI2 AITeAM MIAHO AOTSIMA3HT 23 05 2006 12 24 54 mirrored C development eagle siplab projects AOB2 Thermistor_chain thermistor_master brd Figure E 21 thermistors master top pcb layout not to scale 71 72 APPENDIX E THERMISTOR MASTER CARD TECHNICAL DETAILS 388 gA 23 05 2006 12 23 30 C development eagle siplab projects AOB2 Thermistor_chain thermistor_master brd Figure E 22 thermistors master bottom pcb layout not to scale E 4 COMPONENT ORDER LIST FOR THERMISTOR MASTER CARD 73 E 4 Component order list for thermistor master card Qty Value Device 1 255SB 1 FO9HP 1 FE06 1 1 FE07 1 2 L02P 3 LEDSMM 1 PIC18F66226 I PT 2 SUBMINIATURE 13 1k R EU_R0805 1 4MHz CRYTALHC49S 2 10uF 2 22pF C EUC0805 1 100R R EU R0805 7 100nF C EUC0805 1 4700pF C EUC0805 1 CON MINI FIT 4 CON MINI FIT 4 1 DS2480B DS2480B 1 MAX203ECWP MAXOOGECWP 1 PC104 DIM PC104 DIM Parts S1 RS232 PORT ICSP DEVICE SEL 1 WIRE INPUT 1PPS ERROR LED LED ON OK LED PIC18F6622 ADD DEVICE ERASE LIST R2 R3 RA
42. o sas 46 509 cre cupa T 108 27Hz f lt 52 796kHz gt Apre amp 1 04 4 Apre amp ap 36 17dB f 52 796kHz A gay 45 592 Apre_amp_dB 33 174 B E gt 00 gt Apre amo 0 A nese oodB C 3 Bandwidth 108 27Hz lt Bye amp lt 52796 Hz The upper cutoff frequency depends on the opamp open loop gain wich is dependent of temperature Temperature range 0 C lt Tamb lt 70 C Opamp open loop gain 800 V mV Avor 3400 V mV Pre amp upper cutoff frequency 12423 4H z lt aap ou pass lt 92796 H z C 4 Noise LT1113 Input Noise Voltage Density 1Hz 50 nV V Hz Input Noise Voltage Density 10Hz 17 nV V Hz Input Noise Voltage 0 1Hz 10Hz 2 4 uV Input Noise Voltage Density Typical Ewnitenoise 1000Hz 4 5 nV VHz Input Noise Voltage Density Maximum 1000Hz 6 nV v Hz Input Noise Current Density Iypitenoise 10Hz and 1000Hz 10 f A v Hz Corner Frequency fac 120 Hz Table C 1 1113 noise characteristics Hydrophone bandwidth 1Hz lt Bhyd lt 28kHz C 4 NOISE 49 Pre amp bandwidth 108 2 6 H gt Dema 0219012 Noise bandwidth BnoisE T Apre ampl dw Apre_ amp maa 2 64 3988 jw 2xmx52796 Foo dw 4 f 275000 275000 mai zb 64 3988 2 da For the noise calculus it was considered that the noise bandwidth is equal to the input signal bandwidth hydrophone bandwidth R3 5 tjun TgocyRi
43. of the strength member and used to securely attach the array to the buoy using a shackle The shackle is made of plastic to avoid parasitic sounds when in contact with metal e bottom thimble fasten to the bottom of the strength member and used to secure the ballast weights e ballast made of lead weights for keeping the array vertical when underwater The array technical specifications including the electronic parts are described in ta ble A 1 of appendix A Care must be taken with all the hardware parts specially bending of electrical cables water sand or other contaminant in the connectors sensor cases or strength member 11 12 CHAPTER 3 USER MANUAL 3 3 Pre deployment procedures 3 3 1 Hardware The following steps must be followed for safe array deployment 1 read the pre deployment procedures for the AOB2 buoy 2 check if the top and bottom thimbles are correctly tighten to the strength member 3 check if the top and bottom thimbles have pvc electrical tape around to prevent acoustic noises 4 attach the ballast weight to the bottom thimble using a shackle 5 secure the shackle using plastic cable ties 6 arrange the array in the deck in an 8 shape assuring that the top end is the ballast first in the water T attach the array to the buoy connecting the top thimble with the array support in the buoy using a shackle 8 secure the shackle using plastic cable ties 9 check the connectors o rings if
44. ompared for example to a dedicated temperature compensated oscillator 36 CHAPTER 4 SYSTEM REFERENCE The DS2480B is an interface chip designed to connect masters with UARTs or 5V RS232 interfaces to the 1 wire bus figure 4 21 This bridge allows any host with a very simple serial communication UART to generate properly timed and slew controlled 1 Wire waveforms The DS2480B receives escaped commands and data performs 1 Wire operations and returns the result back to the host To establish communication with the RXD 1 Wire bus E 1 Wire master HOST UART DS2480B u or PC serial bridge 1 Wire 1 Wire p slave slave TXD Figure 4 21 DS2480B usage simplified bridge the UART must be configured to e Baud Rate 9600 bauds e Data 8 bits Parity None e Stop Bits 1 e Flow Control None This is the startup default configuration to access the bridge and is the configuration used by this system If necessary after the communication is stablished it is possible to negotiate faster rates 115 2kbps 57 6kbps and 19 2kbps An example of the physical connection of the DS1480B with the microcontroller is displayed in figure 4 22 Differences between this circuit and one used in the system is only the absence of the two diodes Pin Vpp may be connected to 5V if the master don t need to program any slave s EEPROM otherwise this pin must be connected to 12V In our system the
45. or serial port 2 and additionally the line coef 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 which is the compensation value to be applied to each individual sen sor Data is written to the file AOB data termchain data log at the interval at which it is received from the thermistor chain Each data line in the termchain data log file is of the following format 09 11 2006 05 10 12 23 250000 23 062500 22 875000 22 937500 22 937500 23 062500 22 937500 22 875000 22 875000 22 812500 22 812500 22 750000 22 937500 22 750000 23 000000 23 000000 23 312500 3 4 DEPLOYMENT RECOVER AND POST DEPLOYMENT PROCEDURES 13 The first fields are date and acquisition time then followed by the temperature sensor readings in degrees C separated by the comma delimeter 3 4 Deployment recover and post deployment pro cedures The steps for a safe recovery and storage of the array are as follows 1 read the deployment procedure for the AOB2 system The array is the first element to enter the water starting with the ballast Pay attention to the sea current to avoid entangling the array under the ships propeller 2 read the recovery procedure for the AOB2 Buoy 3 after the buoy is on the deck start pulling the array out of water If possible arrange the array in an 8 shape immediately 4 wash the array and the buoy with fresh water 5 remove the electrical connectors Pay attention not to loose the connector s o rings 6 place the dummies in the buoy an
46. plab projects Array2 Preamp Figure D 4 pre amplifier top pcb layout 59 56 APPENDIX D PRE AMPLIFIER ELECTRONIC SCHEMATICS AND PCB 22 11 2006 18 18 07 C development eagle siplab projects Array2 Preamp final 4laye Figure D 5 pre amplifier bottom pcb layout D 4 COMPONENT ORDER LIST FOR PRE AMPLIFIER BOARD D 4 Component order list for pre amplifier board Quant Component Referenc Value Vendor 1 Resistor R1 10MQ 0805 1 250ppm Farnell 9238115 1 Resistor R2 1kQ 0805 0 1 5ppm Farnell 1108863 1 Resistor R3 63 4kQ 0805 0 1 10ppm Farnell 1140998 2 Capacitor C2 paralelo 1uF 0805 25V 10 Farnell 8805687 cer mico 2 Capacitor C2 paralelo 0 47uF 0805 25V 10 Farnell 8805679 cer mico 7 Capacitor C1 C5 C6 C7 100nF 0805 50V Farnell 9406387 C8 C13 C14 cer mico 1096 2 Capacitor C4 C11 1uF Case A 35V Farnell 3037897 tantalum 10 2 Capacitor C9 C10 0 47uF Case A 35V Farnell 967269 tantalum 20 1 Voltage L7908CV L7908CV Farnell 9756248 regulator 1 Voltage IC3 MC78M08 Farnell 1087192 regulator 2 Diode D1 D2 FDLL300 Low leakage high Farnell 9843779 conductance 1 opamp IC1A LT1113 LT1113CS8LMD Linear Tech credit card www linear com 1 Balanced line DRIVER SSM2142 SSM2142S Farnell 9426329 driver 1 hydrophone Hydrophone1 SQ26 Sensortech www sensortech ca 1 PCB PCB PCB www pcbtrain co uk Figure D 6 pre am
47. plifier component order list 57 Appendix E Thermistor master card technical details E 1 DS18B20 PAR addresses THERMISTORS DS18B20 PAR 1 8E000000DBAF0328 Sample 2 2 C5000000DBBE1B28 X Sample 16 ojojojojojojojojojojojojo ojojojojojojo o I i i Ce rl i i I i O e i be dd e i A i ES I i e ul I i N N N e la oO mr pwr par pa wiwi Go bo WIM Oo T E T T T Li Li T T lo l kll Figure E 1 DS18B20 PAR addresses E 2 PIC18F6620 SOFTWARE FLOWCHARTS E 2 PIC18F6620 software flowcharts START Power ON Reset address 0000h startup routine microprocessor 3 LEDs ON Initialize PIC s UART n 1 to communicate with the 1 wire bridge 9600 bauds 8bits no parity 1 stop bit no flow control Initialize PIC s UART n 2 to communicate with the host computer 19200 bauds 8bits no parity 1 stop bit no flow control Send message 1 WIRE THERMISTORS ARRAY to the host Call DS2480B_DETECT Initialize the communication with the 1 wire bridge Configure PIC s timer0 as time base for acquisition Timer0 49152 Timer0 prescaler 1 256 16 bits counter gt 2 65536 65536 49152 16384 16384 x 256 4194304 cycles 4MIPS gt 250ns 4194304 x 250ns 1s Enable timer0 interrupt ON LED ON Go to MAIN routine wait for interrupts signaled by timer0 overflow from
48. pre amplifier circuit a esie d qid ue eol les AA qutd power supply cable ire ud eA ee ies Xm er etse Mie e Bg cables and connectors overview a thermistors cable and connector overview oa a e a 0004 thermistors master card ss ssa Ei Ge Ae todo S pto X ER thermistors master card power up flowchart JT hernstors Pinout y e uil es MA dg Bl dy dos mue Vd ex DS18B20 PAR typical error curve P Soit P EON OE EGRE Een Re YU Sex Ke 64 bits lasered rom code T de Diu bite ad nt l wire bus linear topology scie e 379 eue X SUR SEU o undis DS18B20 PAR s parasite power circuit and internal block diagram DSISB20 wy nr E LETTER DS18B20 PAR memory chart a IB a qr HE a pa m DS18B20 PAR temperature registers format a DOW CRC generator Lau gia er E orata aio 1352480B usage simplified Ei vro ore Wee ala DS2480B circuit example ss ui a A ee Be ee a R C filter helps DS2480B interfaces on short to medium networks thermistor chain s electronic ruit 222 ol so a PIC programming schematic tres reet x ORG ie Thermistors acquisition software algorithm Pre amphnee einen us Veber Prada Aaa e Bn e SN De SE d Hydrophone pre amplifier 2 ams a4 ps he y GE ete pre amplifier top components placement lcs pre amplifier bottom components placement lcs pre amplifier top pcb layout lt a pre amplifier bottom pcb layout o a a a pre amplifier componen
49. son to send the whole scratchpad to the master is that a CRC code is included to validade the whole packet and not only the temperature values Temperature values have a resolution of 9 10 11 or byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7 byte 8 12 bits 0 5 C SCRATCHPAD Power up State Temperature LSB e 8s c Temperature MSB 05h EEPROM Ty Register or User Byte 1 Ty Register or User Byte 1 Tr Register or User Byte 2 Tr Register or User Byte 2 Configuration Register lt gt Reserved FFh Reserved 0Ch Reserved 10h CRC Power up state depends on value s stored in EEPROM Configuration Register Figure 4 18 DS18B20 PAR memory chart 0 25 C 0 125 C 0 0625 C user configurable in the configuration register The temperature data is stored as a 16 bit sign extended two s complement number in the temperature register figure 4 19 The signal bit is bit11 and his values is extend from bit 12 to 15 For 11 bit resolution bit 0 is undefined for 10 bit resolution bits 1 and 0 are undefined and for 9 bit resolution bits 2 1 and 0 are undefined Table 4 8 shows some examples between temperature values and binary code At power up the 43 THERMISTOR CHAIN ELECTRONICS 33 bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 LS Byte 2 27 2 29 3 2 2 2 bit 15 bit 14 bit 13 b
50. stor reading software Data is received from the Digital Thermistor Acquisition Board through the serial port The software in python is a program which reads every line which comes in over the serial line and saves the respective data in an internal table The table is filled when the Thermistor Chain signals at begin of transmission For each acquired sensor there exists a compensation value which is added to the read value Data is stored in A0B data termchain data log where each line represents a complete acquisition cyle of all the channels The source code shown in table 4 12 in python reads the data from the thermistor chain using the serial port 4 4 Array system testing The various system components were individually tested using computer simulators pre amplifier and thermistor chain board lab tested either separately or connected together and mechanically tested both in pool and at sea and during a sea trial RADAR 06 Several changes were introduced to the system in particular to the pre amplifiers design during these various testing phases The description made in this report reflects only the final design and is supposed to fulfill the requirements of the sponsor projects 44 ARRAY SYSTEM TESTING 41 power ON Configure acquisition time to 5 seconds Microntroller s timer0 Inform user about system power up Green LED blinks Send 1 WIRE THERMISTORS ARRAY to host computer ON LED ON Wait for
51. t order list DS18B20 PAR addresses os Power NO zi Soi eee e iu NS utu ier quoe fe ENG O ut f Timer int rr upt a E babet VI LIST OF FIGURES E 4 Acquisition routine flowchart 1 of 4 agua ap ok wa 61 E 5 Acquisition routine flowchart 2 of 4 seus sre GE a 62 E 6 Acquisition routine flowchart 3 of 4 se pi ORY Es 63 E T Acquisition routine flowchart 4 of 4 o 63 E 8 DS2480B DETECT subroutine eo e Rap e Dc Dro 64 E 9 DS2480B POWER ON RESET subroutine 65 E 10 D82480B SET TIMING subroutine 65 E 11 DS2480B_ DATA MODE subroutine aooaa 65 E 12 DS2480B_ COMMAND MODE subroutine 65 E 13 OWRESET subroutine A ge ak Ad ei oi 66 E 14 OWWRITEBYTE subroutine oo a e ee rx 67 E 15 OWREADBYTE subroutine 22e 67 E 16 DS2480_ STRONG PULLUP ON subroutine flowchart 68 E 17 DS2480 STRONG PULLUP OFF subroutine flowchart 68 E 18 DS2480_ TERMINATE subroutine flowchart 68 E 19 thermistors master top components placement not to scale 69 E 20 thermistors master bottom components placement not to scale 70 E 21 thermistors master top pcb layout not to scale o oaoa aa 71 E 22 thermistors master bottom pcb layout not to scale 72 E 23 component order list for thermistors master card 73 G 1 hydrophone case mechanical design design 2 22 75 G
52. t voltage range referenced to ground Differential output voltage range Vour dif 10V 46 C 2 PRE AMPLIFIER GAIN 47 C 2 Pre amplifier gain Assuming that the lt1113 is an ideal op amp and ignoring Ci Ha Aideal 1 1 1 jwC2R2 f E 108 27H x fe V HP_ 3dB OnC R 2x7x 1 47x 10 6 x 1000 f gt 0Hz gt Arpgar l ArpEAL ag 0dB f gt 108 27Hz gt AIDEAL 0 7079 x 64 4 AIDEAL dB 3 36 17 d B f 00 gt AIDEAL 1 na 64 4 Arppar dB 36 17dB Which is the same as a high pass filter with 1 pole and 3dB cutoff frequency at 108 27 H z Including capacitor C gives E 1 Aideal 1 Fe 1 x 1 1 jwC2R2 PE jwCi Ry fupa 50 xxxidsde 5doxig 0 16Hz far2 xo sro 108 27H2 f gt 0Hz gt AIDEAL O AIDEAL dB oodB f gt 0 16Hz gt Arprar 0 992 AIDEAL dB 69 49dB f gt 108 27Hz gt ArpgaAr 45 592 ArpEAL ag 33 17dB f 00 gt Area lc 044 ArpgaL ap 36 17dB Assuming taht the opamp has a finite and frequency dependent gain AvoL tipica 3400 V mV 130 634 B fo 101113 lHz wp tt1113 27rad s AVOL pl a opamp jo Wp lt1113 a Har y 1 Ro 1 a juCa 1 48 APPENDIX C PRE AMPLIFIER ELECTRONICS CALCULUS When f 00Hz a 64 3988 Pippe ata R 1 ju 1 a r r T Zxsx52796 gt UH gt gt Aste ni 0 Aa oodB f 046Hz Ansans 0 900 JA dp co cd dB f gt 108 27Hz B
53. te with the 1 wire slave devices DS18B20 PAR through the DS2480B e communicate with the host computer through an rs232 serial port interface 4 3 THERMISTOR CHAIN ELECTRONICS table 0 255 0 94 188 226 97 63 221 131 194 156 126 32 163 253 31 65 157 195 33 127 252 162 64 30 95 1 227 189 62 96 130 220 35 125 159 193 66 28 254 160 225 191 93 3 128 222 60 98 190 224 2 92 223 129 99 61 124 34 192 158 29 67 161 255 70 24 250 164 39 121 155 197 132 218 56 102 229 187 89 7 219 133 103 57 186 228 6 88 25 71 165 251 120 38 196 154 101 59 217 135 4 90 184 230 167 249 27 69 198 152 122 36 248 166 68 26 153 199 37 123 58 100 134 216 91 5 231 185 140 210 48 110 237 179 81 15 78 16 242 172 47 113 147 205 17 79 173 243 112 46 204 146 211 141 111 49 178 236 14 80 175 241 19 77 206 144 114 44 109 51 209 143 12 82 176 238 50 108 142 208 83 13 239 177 240 174 76 18 145 207 45 115 202 148 118 40 171 245 23 73 8 86 180 234 105 55 213 139 87 9 235 181 54 104 138 212 149 203 41 119 244 170 72 22 233 183 85 11 136 214 52 106 43 117 151 201 74 20 246 168 116 42 200 150 21 75 169 247 182 232 10 84 215 137 107 53 35 Table 4 10 DOW CRC lookup table Current CRC Value Input Data New Index
54. the buoy using an inox shackle 4 1 3 Bottom Thimble Bottom ring to connect the array to the ballast using an stainless steel shackle 4 1 4 Strength Member The strength member is a 6mm Dyneema cable with a very low stretching factor and breaking load of 1500 Kg It goes from the top to the bottom of the array inside the protection sleeve and connects the top thimble with the bottom one As it has a very low stretch factor the sensors in the array are fasten to this cable to be assured a fixed and stable position 15 16 CHAPTER 4 SYSTEM REFERENCE Top Thimble Hydrophone s Thermistor cass sensor s mold Polyamid protection Sleeve Strength member Bottom Thimble Ballast e lead I Figure 4 1 Mechanical Overview 4 1 5 Ballast At the bottom of the array there is a 8kg ballast made of lead weights to keep the array under tension and as vertical as possible The used weights are the same as scuba divers and are fastened to the bottom thimble using a strap figure 4 2 Bottom Thimble A 8kg Figure 4 2 Ballast 4 1 6 Hydrophone Protection Case A protection case was specially designed to keep the hydrophone and preamplifier elec tronics protected from the environment and to help fasten the hydrophone to the strength member at a known fixed depth position Polyurethane resin UR5041 RS code 1608481 42 HYDROPHONE ELECTRONICS 17 is used to fill the case and isolate the electron
55. timer0 timeout E Timer0 timeout ACQUISITION LED ON Send command to all slave devices acquire their actual temperature at the same time Read the temperature from sensor 1 up to 17 in this order Send the temperature message header TEMP to host computer Convert the temperatures to ascii characteres and send the values to the host computer ACQUISITION LED OFF Restart timer0 Figure 4 26 Thermistors acquisition software algorithm 42 CHAPTER 4 SYSTEM REFERENCE usr bin python2 4 import string import serial import time import datetime from string import atof filename AOB data termchain data log ser serial Serial dev ttyS1 19200 timeout 1 FILE open filename a data range 17 coef range 17 coef 0 0 0 0 0 0 0 050 0 0 0 0 0 0 0 0 begin 2 x ser read read one byte s ser read 10 read up to ten bytes timeout while 1 lt 2 line ser readline read a n terminated line print line strip if line strip TEMP begin 1 today datetime datetime now datestring today str time 02e 2m 4Y 2H 2M 28 if begin gt 1 and begin lt 17 tmp line strip data begin atof tmp adicionar correct de temperatura aqui data begin data begin coef begin begin 1 if begin 1 begin 1 if begin 17 begin 2 dataline Ms hE LEME Mf hE hE AE AE AE hi AE AE VE AE AE HE A datestring
56. uart with the computer s RS 232 serial port One 4 MHz cristal sets the microcontroller s working frequency Input buttons are implemented on the circuit but the current microcontroller software doesn t support them All the connectors on the card and the LEDs functions are described in section 4 3 3 and in figure 4 10 4 3 11 1 Microcontroller s frequency The microcontroller frequency is set by the 4MHz crystal 13 16M Hz PIC mode HS PLL gt fo ferystal X 4 16M Hz gt AMIPS 4 3 11 2 Microcontroller s programming The circuit designed has an error in the programming connector ICSP connector and the programmer can t be directly connected to this port to program the PIC To make programming possible all the PIC s Vcc pins must be disconnected from the circuit and routed only to the programmer Figure 4 25 ilustrates these changes 3The actual circuit probably work if Microchip ICD2 programmer is used but this was not tested SYSTEM REFERENCE CHAPTER 4 38 T T neeus E TZ k1 900Z 01 TT 9120 148qunwN ueunoog o ABISEUT AO SIWISYI 337111 Asirasvua 301A30 09Y ALYOdZZ99481O Id 4LYOdZZ9948191d 3LYOdZZ994819l1d TSIMMI QLHOdct9948lOld z Sddi LndNI i Sddi LfidNI uud IN xp 037 40 quo x 00 A AN c 91MOdZZ004819ld 21OdZ0994812Id ESSI quo quo
57. unication with the DS2480B Send 0xE1 to the DS2480B Flush the uart input buffer Figure E 11 DS2480B_ DATA MODE subroutine DS2480 COMMAND MODE Set command mode communication with the DS2480B Send 0xE3 to the DS2480B Flush the uart input buffer Figure E 12 D82480B COMMAND MODE subroutine 66 APPENDIX E THERMISTOR MASTER CARD TECHNICAL DETAILS OWRESET Reset error counter Error_timeout 0 Call DS2480 COMMAND MODE 1 wire reset Send b 11000101 to DS2480B Read the bridge response Check if the bridge IC is the DS2480 or the DS2480B Y IC DS2480B The bridge is ok and its response Error returns the 1 wire bus status Increment error counter Error timeout Wait 6 miliseconds Error timeout threshold Flush the uart input buffer Y END return the 1 wire status Send message RESET OWRESET to the host Reset the microcontroller by software Figure E 13 OWRESET subroutine E 2 PIC18F6620 SOFTWARE FLOWCHARTS 67 OWWRITEBYTE Tx_val Byte to be transmitted to the 1 wire bus N Call DS2480 DATA MODE E Send the byte tx val value to the DS2480B aee Send the byte tx val value one second time to the DS2480B Data mode is the current mode END return the 1 wire response byte Figure E 14 OWWRITEBYTE subroutine OWREADBYTE N Call DS2480 DATA MODE Send 0xFF to DS2480B END return with the byte that was
58. ures from the array continuously The card reads the 17 values approximately every 5 seconds and sends the readings in ASCII 4 3 THERMISTOR CHAIN ELECTRONICS 27 format to the serial port The acquisition timing is obtained from the microcontroller s cristal oscillator taken as reference clock 4 3 2 Power up Figure 4 11 shows the power up flowchart Power ON Send message 1 WIRE THERMISTORS ARRAY to the host Left Red LED ON Middle Green LED OFF Right Red LED OFF Read Temperatures and send the values to the host Acquition Period 5 seconds Green LED ON Figure 4 11 thermistors master card power up flowchart 4 3 8 Status LEDs The board s LED s show the status of the system coded as follows e ON LED Left Red The microcontroler set this Led ON when the card is powered ON e ACQUISITION LED Middle Green LED This Led is ON when the micro controler is acquiring one set of 17 temperatures and returns to OFF when the acquisition ends e ERROR LED Right Red This LED is turned ON every time one error occur At the same time one error message is sent through the serial port to the host computer 4 3 4 Serial Interface Configuration In order to receive the data from the card an RS 232 interface with the following config uration is necessary 28 CHAPTER 4 SYSTEM REFERENCE Baud Rate 19200 bauds Data 8 bits Parity None Stop Bits 1 Flow Control None 4 3
59. w 108 27Hz Bpre amp 52796H z ue au no 12423 4H z Bpre amp 52796Hz Preamp bandwidth Temperature range Top frequency variation full temperature range 4 2 2 5 Noise Ignoring the noise from the balanced line driver which is not specified on the datasheet 5 the preamplifier noise main sources are the operational amplifier voltage and current noise Table C 1 and the thermal noise on the resistors All together give a final output noise of En ou 4 5019 mV Taking into account a pre amplifier output range of 5V gives for a sine wave at 1 kHz an output RMS voltage Vou RMS a 3 5355V and therefore 3 5355 785 34 4 5019 x 1073 that in dB gives 201og 785 57 897dB The complete calculus to obtain these values is shown in appendix C 4 Attention must be payed to the fact that during the noise calculus the noise bandwidth was assumed to be equal to the input signal bandwidth and not to the total noise bandwidth 4 2 3 Cables and Connectors The cabling system is designed to provide power to all the hydrophone pre amplifiers and to bring the electrical signals from each hydrophone pre amp to the surface buoy input connector 22 4 2 3 1 Power supply cable CHAPTER 4 SYSTEM REFERENCE The power supply cable is a three wire cable where each pre amplifier is connected in a bus topology figure 4 7 Table 4 4 shows the cable s properties FA 12V 7N s leng morrn L Mo lum
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