USER MANUAL The CM2 SIDESCAN SONAR SYSTEM
Contents
1. 4 AUV I F PCB Vehicle computer or multiplexer These cables are wired as follows Cable A 5 way 3 81mm pitch connector J1 to Micro BH 5F S S bulkhead socket Cable B 5 way 3 81mm pitch connector J2 to Micro BH 5F S S bulkhead socket Cable C 2 way 0 1 pitch connector J5 to 2 way XH250 connector J2 Cable D 3 way 0 1 pitch connector J6 to 3 way XH250 connector J3 Cable E 2 way XH250 connector J1 1 GND J1 2 10 28VDC Cable F 5 way XH250 connector J4 3 GND J4 4 USBDATA J4 5 USBDATA if LK1 is fitted or Cable F 5 way XH250 connector J4 1 RS232 Rx J4 2 RS232 Tx J4 3 GND if LK2 is fitted All cables are supplied by C MAX though their length may need to be adjusted by the installer Cables A through D are wired one for one that is pin 1 on one end connects to pin 1 on the other and so on Assembly of Cables A and B can only be completed after the bulkhead connectors have been screwed into position These two cables should each be a tightly twisted bundle to minimize the sensitivity to electrical noise For ROV installations where the Towfish PCB is housed in a Sonar Bottle Cable C and Cable D must pass through additional bulkhead connectors usually a 6 way connnector Micro BH 6M S S on the bottle and a Micro BH 6F S S on the ROV body Grounding The isolated pad that includes the single M4 hole in the Towfish PCB located centrally at one end should be electrically connected to the vehicle s bo2. Hz primarily acting as an echo sounder to determine altitude but also ensuring that the ground directly below the vehicle is included in the acoustic coverage The transducers are handed left and right for projection either side of the vehicle The only difference between them is the end to which the cable is attached Towfish PCB The Towfish PCB is similar to that fitted in the towfish body in systems designed for towed operation except that the heatsink required by the mixing of data and power on a 2 wire tow cable is not fitted The Towfish PCB drives the sonar transducers and interfaces to an AUV I F PCB through which it communicates with the acquisition PC The Towfish PCB supplies the transducers with regular high voltage ping pulses and then amplifies filters and digitizes the echoes The Towfish PCB also acts as a transceiver for the the link to the acquisition PC via the AUV I F PCB The link transmits sonar data status data and commands AUV I F PCB The AUV I F despite its name can be applied to both ROV and AUV configurations The AUV I F PCB decodes the data from the sonar head passing it via a USB link to the onboard computer or umbilical muliplexer Commands are passed to the sonar head via the same link As an alternative to USB an RS232 inferface is available if the zero ohm link is removed from LK1 and fitted to LK2 The AUV I F PCB generates clean 24VDC power for the Towfish PCB Voltage isolation between th
3. USER MANUAL The CM2 SIDESCAN SONAR SYSTEM AUV ROV Supplement Version 1 2 Contents CONTENTS 1 Introduction 2 System Components Sonar Transducers Towfish PCB AUV I F PCB Sonar Transceiver STR 3 Installing the System 5 Transducers Circuit Boards Interconnection Wiring Grounding Version 1 2 2011 i Version 1 0 2011 1 Introduction 1 INTRODUCTION The CM2 Sidescan Sonar is normally configured as a towed system where the sonar head is referred to as a towfish The key elements of the sonar head namely the transducers and the Towfish PCB are also suitable for mounting in an autonomous underwater vehicle AUV These items are also equally suitable for mounting on a remotely operated vehicle ROV with the electronics protected by a pressure housing An additional electronics board the AUV Interface PCB AUV I F handles all communication between the sonar head and the onboard computer or alternatively in the case of an ROV an umbilical multiplexer The AUV I F also generates clean power for the Towfish PCB This supplement should be read in conjunction with the latest version of the CM2 User Manual Version 1 2 2011 1 2 System Components 2 SYSTEM COMPONENTS Sonar Transducers Two faces of each sonar transducer are active The main face transmits and receives at the two selected frequencies 325kHz and either 780kHz or 100kHz the lower face transmits and receives at 325k
4. ay need to be supported centrally to meet vehicle shock specifications If so it should be gripped at its edges using material that will not damage the laminate The location of the AUV I F PCB is less critical than that of the Towfish PCB but it is again good practice to minimize the possibility of noise coupling into the PCB and its cabling Version 1 2 2011 4 TRANSDUCER RH CORRECT ANGLE 173 NOM TOWFISH PCB MAIN FACE 3 Installation TRANSDUCER END VIEW 9 0 MOUNTING DIMENSIONS i BOTH ENDS SYMMETRICAL LH TRANSDUCER IS MIRROR IMAGE OF RH TRANSDUCER 50 4 LOWER FACE 5 1X3 CASE GROUND AUV I F PCB SONAR BOTTLE ROV OPTION ONLY RESERVE THE SHADED VOLUMES FOR COMPONENTS AND AIRFLOW ABOVE AND BELOW THE PCB S EXCEPT WITHIN A 5MM RADIUS OF THE MOUNTING HOLES ALL PCB MOUNTING HOLES EXCEPT CASE GROUND ARE 3 1MM DIAMETER AND ARE ELECTRICALLY ISOLATED CASE GROUND IS 4 1MM DIAMETER CASE GROUND SEAWATER GROUND Mounting dimensions all to scale Version 1 2 2011 3 Installation Interconnection Wiring The wiring between the various elements is as follows Cable A J1 Towfish PCB LH transducer via bulkhead connector Cable B J2 Towfish PCB RH transducer via bulkhead connector Cable C J5 Towfish PCB J2 AUV I F power to Towfish PCB Cable D J6 Towfish PCB J3 AUV I F data and commands Cable E J1 AUV I F PCB Vehicle power rail Cable F J
5. dy or seawater ground This seawater ground is capacitively coupled to OV on the Towfish PCB Note that power to the Towfish PCB is provided by an isolated supply so its local OV is independent of the AUV I F PCB ground The AUV I F ground must be directly connected to the vehicle s logic ground C MAX Ltd 2011 Version 1 2 2011 6 This page intentionally blank Version 1 0 2010
6. e AUV I F and Towfish PCB s is maintained for both power and data communication This allows the electrical grounds of the sonar and the vehicle to be independent from each other The PCB requires DC power in the range 10 28V at 3W In standby mode the power requirement reduces to 0 5W Sonar Transceiver STR certain ROV installations only As described in the main CM2 User Manual the primary type of surface electronics unit for the towed CM2 system is the Sonar Transceiver or STR This unit provides power for the towfish via the tow cable receives the echo data and other information such as the towfish altitude and sends commands to the towfish lt needs only a 2 wire link for this communication unlike the AUV I F PCB which needs 4 conductors An STR is included in an ROV configuration only when that configuration closely resembles the standard towed system that is when the sonar head transducers and Towfish PCB is linked to the surface directly by a single pair of dedicated conductors in the ROV umbilical In this configuration an AUV I F PCB is not required STR s were also employed in early AUV installations but this role has been replaced by that of the AUV I F PCB Use of the STR is not discussed further in this supplement Version 1 2 2011 2 2 System Components Transducers and Circuit Boards Version 1 2 2011 3 3 Installation 3 INSTALLATION Transducers Each transducer in its backing plate is 512mm l
7. ong overall with its cable extending a further 173mm to a wet pluggable Micro IL 5M connector The transducer cables can extend rearwards as in the towfish installation but the alternative configuration with the transducers exchanged and both cables extending forward is equally satisfactory The transducers should be installed with their long sides horizontal and their main faces pointing approximately 10 degrees below the horizontal The main face needs to be unobstructed for its full length the lower face needs to be unobstructed only for the central 100mm of its length However if the vehicle s design prevents the lower face having an unobstructed view the system is supplied with an alternative version of the sonar head s firmware programmed into the microcontroller on the Towfish PCB In ROV installations the transducers are often mounted some distance apart on opposite sides of the vehicle Transducer extension cables are available to accommodate this Custom shapes of transducer and backing plate are available to special order The detail drawing of the backing plate is also available to assist any customer who wishes to manufacture a modified version Circuit Boards The Towfish PCB should be mounted as close to the sonar transducers as practicable avoiding any location close to sources of electrical noise The Towfish PCB uses 2 7mm laminate compared with the more usual 1 6mm but it has a long span between mounting points and m
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