The TT801 is a portable remote control system designed for acoustic communication with subsea devices such as Acoustic Releases and Recoverable Transponders. It operates in the low frequency (LF) range of 8-16 kHz, utilizing a highly secure and reliable FSK (Frequency Shift Keying) telemetry link.
Function Description
The primary function of the TT801 is to transmit coded acoustic signals to remotely control the operating modes of Acoustic Releases and Recoverable Transponders. It also incorporates a ranging function for relocating and monitoring subsea units.
Transmission Capabilities:
The TT801 can transmit:
- Single tonal pulses for interrogation: Release transponders typically have two factory-set interrogation frequencies (Individual Interrogate Frequency - IIF, or Common Interrogate Frequency - CIF) ranging from 8.5 to 16 kHz, with 500 Hz steps. Upon receiving an interrogation pulse, an enabled Release Transponder replies with an acoustic pulse (Common Reply Frequency - CRF or Individual Reply Frequency - IRF) after a turn-around time.
- Encoded commands: These are used to monitor the operation of Acoustic Releases or Release Transponders. IXSEA's technique involves an FSK-2 states command burst using 8-bit words with 2-state coding, where logical bits '0' and '1' are coded with two different carrier frequencies. Commands can be a unique "DIRECT" sequence (single 8-bit word) or an "ARM & EXECUTION" sequence (two 8-bit word burst, with the ARM code acting as the address).
- ARM: Precedes commands for OCEANO AR701AE, AR/RT/ET800, AR/RT/ET900 series, acting as a unique address.
- RELEASE: Activates the release operation for AR/RT 600 series, OCEANO AR/RT 800, and OCEANO AR701AE.
- DIAGNOSTIC: Used with RT600, OCEANO AR/RT800, and AR/RT900 series to retrieve verticality and battery voltage information.
- INT/RANGE: Measures distance from the surface to AR600 series acoustic releases.
- WINDOW: Can precede some RT600 series commands requiring an ARM & EXECUTION sequence, acting as an address and enabling range measurement.
- ON FR1-FR2: Enables FR1 and FR2 Transponder channels for RT600 series.
- OFF FR1-FR2-PINGER: Disables FR1 and FR2 Transponder channels and Pinger mode for RT600 series.
- ON FR1-OFF FR2 / ON FR2-OFF FR1: Enables one FR channel and disables the other for RT600 series.
- PINGER: Activates Pinger emission for RT600 series.
- PINGER ON: Activates Pinger emission and disables Transponder mode for OCEANO AR/RT/ET800 and AR/RT900 series.
- ARM/RANGING: Allows distance measurement on OCEANO AR/RT800 series.
- RELEASE with PINGER: Activates both release and pinger emission upon completion of release for OCEANO AR/RT800 and AR/RT900 series.
- TRANSP. IIF TRANSP.CIF / INHIBITION IIF CIF / TRANSP. IIF INHIB CIF / TRANSP. CIF INHIB IIF: Control IIF and CIF Transponder channels for OCEANO RT/ET800 and RT900 series.
- PINGER OFF: Disables and stops pinger emission for OCEANO AR/RT/ET800 and AR/RT900 series.
- ACOUSTIC RESET: Restores default transponder configuration for OCEANO RT/ET800 and RT900 series.
Reception Capabilities:
The receiver section can process:
- Acknowledgement signals of remote control codes (CAF for AR/RT/ET800, AR/RT900 series, or FT0 for AR/RT600 series).
- Information on range and elapsed time.
- Telemetry data, such as verticality and battery voltage for AR/RT800 and RT600 series.
- Detection of acoustic transmissions from free-running Pingers and display of their transmission rate.
Important Technical Specifications
Power Supply:
- Internal rechargeable Lead-Acid battery: Operational for approximately 60 hours.
- Standard AC Mains power supply: 115-230V / 50-60 Hz.
- DC power supply: 18-36V (for battery charging, voltage must be strictly higher than 28VDC).
Single Pulse Transmission:
- Programmable frequencies: 8.5 to 16 kHz (resolution 500 Hz).
- Pulse width: 11 ms.
- Acoustic source level: 190 ± 4dB ref. 1µPa at 1m.
- Transducer beam pattern: omnidirectional ± 3dB.
Command Codes (FSK Transmission):
- Coding: 2 state, FSK, 8-bit words.
- Number of pulses per command word: 8.
- Pulse rate: 100 ms.
- Total duration of one command: 711 ms.
- Least significant bit is transmitted first.
- Transmission of ARM and EXECUTION codes via automatic procedure.
Mechanical/Environmental Characteristics:
- Cabinet: Splash-proof ABS case, weight: 9 kg, dimensions: 356 × 269 × 157 mm.
- Dunking Transducer (Standard PET 801 P-30): Weight with 30m cable: 4 kg.
- Shipping: Dimensions: 790 × 400 × 390 mm, total weight (with standard PET 801 P-30): 27 kg.
- Environmental Conditions: Use inside or outside, max. altitude: 6560 ft, battery operation temperature range: -5 to +50°C, battery charging temperature range: -5 to +30°C, max. relative humidity: 80% up to 31°C (linear decrease to 50% at 50°C), pollution level: 3 (conductive pollution), mains power voltage fluctuation within ± 10%, power supply installation category: II.
Electrical Characteristics (Front Panel Connectors):
- XDC (Transducer Output): SOURIAU 12-way female socket.
- 115-230 VAC Power Supply: JAEGER 3-way male socket.
- 24 VDC Power Supply: SOURIAU 6-way male socket.
- Headphones Input: SOURIAU 4-way female socket (with volume control).
- Serial Port: 9-way "D" male socket for RS232/422 link (Provisional).
Usage Features
- Portable Design: The TT801 is a portable unit, suitable for deployment in various locations on a vessel (bridge, control room, rear deck, rubber boat, dingy).
- User Interface: Features a 16 lines × 20 characters Liquid Crystal Module with backlight for data and function display, and a 20-key keyboard for data input and mode selection.
- Audio Indication: Provides audio feedback during configuration and allows listening to acoustic signals (CAF Acknowledgements, PFR pulses) in seawater via headphones.
- Secure FSK Coded Commands: Ensures multi-path protection for reliable command transmission.
- MFSK and Monochromatic Signal Reception: Capable of receiving both wide-spread spectrum (MFSK) and tonal signals.
- Internal Battery and Charger: Equipped with a rechargeable Lead-Acid battery and a built-in charger, allowing operation from internal power or external AC/DC sources.
- DSP Standby Mode: Optimizes battery autonomy by activating after 20 minutes of inactivity. Pressing any key resumes operation.
- Menu-Driven Operation: Organized into clear menus for TX/RX settings, release, pinger tracking, and options (language, backlight, battery voltage, beep command).
- Configuration Management: Allows immediate configuration of transmission/reception parameters without saving, or saving/loading/erasing configurations from a database.
- Pressure Measurement Telemetry: Supports telemetry of pressure measurements from RT8x1 transponders equipped with pressure sensors, using pulse-to-pulse time modulation.
Maintenance Features
Routine Maintenance:
- Battery Charging (PM01): Recommended every 60 hours of operation or every 3 months in normal storage (temperature > 5°C). Full charge takes approximately 20 hours. The 'LOW' LED indicator turns off when fully charged.
- Inspection and Cleaning of Transducer (PM02): Performed after and before each deployment. Involves rinsing with fresh water, checking the neoprene boot for damage, ensuring the top oil filling screw is in place, and cleaning the boot with soapy solution.
- Measurement of Open Capacitance of Transducer (PM03): Annual basis or whenever required to detect faulty transducers and monitor piezoelectric ceramic performance. A normal PET801P-30 or PET661S-TT with a 30m cable should measure 17.5 ± 2.5 nF. Without cable, it's 14.5 ± 2.0 nF.
Corrective Maintenance:
- Replacing the Battery Fuse (CM01): Procedure for when the ON LED is off and the LCD is blank. Requires a flat blade screwdriver and a 5A-250V battery fuse.
- Replacing the Mains AC Fuse (CM02): Procedure for when the yellow "AC/DC" LED is off with AC mains connected. Requires a flat blade screwdriver and a 5A-250V Mains AC fuse.
- Replacement of Internal Rechargeable Battery (CM03): Procedure for when the battery does not hold charge or fails. Requires a flat blade screwdriver, a 7mm tube spanner, 10 M4-A4 NYLSTOP Nuts, and 2 YUASA 12V – 3.2Ah batteries. Involves disconnecting cables, removing the front panel and chassis, and replacing the battery packs.
Troubleshooting:
The manual provides a troubleshooting guide for common issues such as no display, AC/DC indicator not lighting, and failure to transmit or receive acoustic pulses, with recommended solutions and when to contact IXSEA support.
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