Power (12VDC) is supplied to the Control Console from the SPS. One channel of RS232 communications sends data to and from the LBV via the SPS. In the event that the operator is flashing the LBV with upgraded (or Reflashing the LBV with the current) software, a second channel of RS232 is used; With the Flash cable connected to both a computer and the SPS flash port, the LBV will poll the computer for new software upon LBV start-up. Once RS232 communications are established, the flow of data commences. The data goes from the computer to the Control Console via the SPS. There, it is sent (again, via the SPS) to the LBV until the programming is complete. This is the only time that the second channel of RS232 communications is used.

Inside the Control Console, there is a simple circuit board designed to accommodate the Microcontroller and connections for the SPS, Keypad, Joystick and Vertical Thruster control knob.

Failure modes are uncommon, and fall under the category of communication failure due to mechanical misalignment. Poorly packed consoles, and those subject to rough handling, may develop one of a handful of possible failures. A damaged Joystick, for example, may feel crunchy or loose, and may not operate in a specific direction. It may also cause the LBV to be more responsive in one direction than another. If slight pressure has been exerted on the Joystick for some period of time, the user may find that the LBV thrusts slowly in one horizontal direction when powered-up. Usually, allowing the console to stand free for a few minutes will correct this problem. The general rule is: If the LBV has some type of horizontal thrust anomaly (not associated with a failed thruster), but the Vertical Thruster (and auxiliary equipment) operates properly, the Joystick is probably faulty.

If a (previously properly operating) Control Console has been dropped or handled roughly, it is possible for the Microcontroller Chip to have come loose. Upon cursory inspection, it may not appear to be unseated. Pushing down on it with both thumbs will generally reseat the chip, nonetheless.

In general, if a Control Console failure is suspected, it is a simple matter to unfasten the bottom of the case, and verify that all connectors are seated properly. It may be necessary to perform a continuity check of all conductors from the interior termination of the CC cable to the plug on the SPS-end.

SPS Power and Failure
The SPS is designed to perform several functions, including: taking-in and isolating AC Voltage, providing DC Voltage to the LBV, providing 10 Amp current protection for the supply to which it is connected, providing for immediate GFI protection if any of the three output conductors short to ground, coupling/decoupling data and RF channel 3 video to the 360VDC LBV supply lines, et al.  Being so concerned with the processing of power, The SPS is most likely to have failure modes involving same.

There is very little that can fail on the input-side of the SPS. Here, Line and Neutral are input through the breaker and the Main Power Switch to an Isolation Transformer. Earth Ground is tied to the SPS chassis. The protection on this side consists of the aforementioned 10 Amp breaker, which will trip if (for some reason) the SPS draws too much current from the supplied power. The breaker is on the SPS front-plate, and is reset by simply pushing it in to its seated position.

The transformer supplies AC ‘Line’ to a relay which is normally open. The relay is closed when the user pushes the Power button on the Control Console, and the ‘Line’ and ‘Neutral’ are input to a bridge rectifier, whose output is a filtered ~360VDC. At this point, there are two power conductors: ‘360’ and its ground, ‘Return’. The 360VDC is then sent through a fuse to a switching circuit which is also closed by the Power button on the Control Console. At this point, Data and Video are coupled onto the 360 and Return, and a third conductor is introduced: Shield. From here, 360, Return and Shield are sent out to the LBV.

360 is isolated from, and Return is 50 Ohms above Earth Ground. If, for any reason, current is sensed on Earth Ground, the GFI Circuit will force the relay and switching circuit open. Shield serves a few purposes, but as far as power is concerned, it provides for automatic shutoff of 360VDC power to the LBV (in much the same way as the GFI circuit) in the event that water enters the LBV’s Vehicle Power Supply. SPS power Failure modes include any event in which (upon pressing the Control Console Power button) 360 VDC is not present at pins 2 & 3 of the Umbilical connector of the SPS.

SPS Communications and Failure
As stated before, broadcast CH 3 video is decoupled directly from the 360VDC conductors of the umbilical, and output to the jack on the SPS front plate, but the SPS plays a vital role in inter-system communications, as well, serving as the junction box for all the standard components of an LBV System (as detailed before), as well as for auxiliary equipment, i.e.: Sonar and Tracking. Routing data is a large part of what the SPS does, and how that is accomplished is determined by the Communication Configuration.

Communication configurations are determined by the user’s needs:

OOK (On-Off Keying)
This is the standard mode of communications for the LBV150x. This mode is used for any LBV System that uses 150 Meters of umbilical, does not have Sonar and does not have Tracking. This mode has only 1 data channel (LBV control) and 1 video channel. Communications are controlled by high and low signaling (if LBVs were radios, this would be AM). Due to recent advances in OOK signal-strength and noise reduction, this is the most simple, reliable and affordable configuration available for the LBV.

FSK (Frequency-Shift Keying)
This is the standard mode of communications for the LBV150L², where LBVs using up to 250M of umbilical also support Sonar, Tracking, or both. This mode has 2 full data channels (CH 1-LBV control, CH 2-Sonar), 1 half data channel (Tracking Trigger), and 1 video channel.  Communications are controlled by frequency shifts in the signal (By the above analogy, this would be FM). FSK is required for integration of Sonar and/or Tracking. The ability for FSK to support multiple data signals without any change in the cross-sectional diameter of the umbilical (and without incurring the expense of Fiber-Optic data transmission), makes this configuration a very affordable method of expanding the LBV’s capabilities.

Fiber Optics
This is the standard mode of communications for LBV300s, 410s and 750s, et al. It is also used for special LBV150s, where the customer requires 2-6 RS232 data and/or 2 video channels.  Taking advantage of the multimode fiber-optic line (that usually goes un-terminated) already inside the standard SeaBotix umbilical, this mode is used when the user requires the LBV to go deeper or (in the case of long-line systems) farther, and/or when the user wants 2 channels of video at once. Also (depending on the type of fiber board configuration), the use of fiber optics enables the LBV to accommodate more on-board devices. Please note that in any Fiber Optic Data configuration, there exists the capability of utilizing 1 RS 485 data channel.

Umbilical Power and Failure
Since the standard umbilical consists of two conductors and one shield, its simplicity lends itself to few failure modes. It is possible for a failure to be intermittent. Flexing of the umbilical at both the SPS and LBV ends is recommended when performing continuity and voltage checks as per the previous troubleshooting steps. A failure in any check will require that the Umbilical be returned to the factory for repair.

Umbilical Communications and Failure
In LBV Systems (not using Fiber Optic data transmission), the Umbilical Shield acts as a barrier, keeping RF noise outside, maintaining signal strength, and preventing LBV System signals from interfering with other RF equipment. A failure of the shield renders the LBV System susceptible to outside interference and signal loss. If there is an open in the Shield, the user may experience intermittent communications, loss of communications or poor video quality. If the Umbilical suspect, please perform a continuity check on pin 1 between the SPS and LBV ends of the Umbilical.

LBV Power and Failure
As mentioned before, the LBV is supplied with 360VDC. The pin configuration on the 3-conductor male bulkhead connector (aft, on the port side of the LBV) is: 1 = Shield, 2 = Return and 3 = 360VDC. Once inside the standard LBV, these power lines are connected to the Vehicle Power Supply (VPS, consisting of the RF Coupler board and the Power Supply Interface Board), where the RF Video and Data are decoupled from the power lines (on the RF Coupler board). The power lines are then immediately fed into a 360VDC to 28VDC converter. The need for GFI protection requires that the LBV ‘Ground’ is kept 50 Ohms above Earth Ground. Since the Return line of the SPS is already in this state, the Ground for the LBV is electrically the same point as Return in the SPS and Umbilical. The 360VDC and 28VDC are electrically isolated from one another.

28VDC is the basic supply for all components inside the LBV. The converter’s output is augmented with a power-control circuit (the Power Supply Interface board) that provides two isolated sources (one switched, and one un-switched) of 28VDC for distribution to the Motherboard and the Backplane. The un-switched 28VDC is sent immediately to the Motherboard when 360VDC is applied to the converter. Unlike the Motherboard supply, the Backplane supply is controlled by switching circuitry. Initially energized by the Motherboard, this circuitry will provide power to the Backplane as long as normal conditions exist. If a short is present on the Backplane, power will be shut-down by this circuit.

The Backplane
The Backplane serves not only as part of the framework for the LBV, but also as the watertight electrical connection for all the external dynamic components of the LBV. These components include all 4 (or 6) thrusters, the External Lighting System (ELS) and the Three Jaw Grabber (TJG).

Each Backplane component has a 4-pin connector, two of which are 28VDC and Ground (as will be iscussed later, the other two pins are Data and Clock). To keep the LBV small, powerful and affordable, all components on the Backplane share a common power supply. If any component should short on its power pins,    for any reason, all power to the Backplane will be shut down until the short is removed.  

The Motherboard
The Motherboard is initially supplied with 28VDC form the VPS. There, the 28 VDC is distributed to the 12VDC regulator and the Lamp Circuit supply (control for the Lamp Circuit comes from the Microcontroller on-board). The 12VDC regulator distributes some of its output to the 5VDC regulator, and both then distribute their outputs to all the devices that require these voltages. These voltages can easily be visually monitored, as each has a corresponding LED assigned to them on the Motherboard (as shown in ‘Troubleshooting Aids’).

It is rare to have a Motherboard power failure, unless the LBV Camera Housing has flooded. Another probable cause of Motherboard power failure would be limited to the 5VDC supply, where specialized, after-market equipment (powered by the 5VDC regulator) draws excessive current. If this occurs, the 12VDC LED will be lit continuously, but the 5VDC LED will flicker, blink or remain unlit. In the event that this should happen, the equipment configuration may need to be reviewed.

LBV Communications and Failure

As discussed earlier, there are several different modes of system communication. Since the majority of LBV systems are not fiber optic, this will be discussed under the ‘Special Equipment Section’. In this section, Video will be considered a form of communication.

OOK and FSK Equipment
In most systems, the LBV’s key communication devices are the RF Modulator Board and the LBV Data Board. These boards transmit and receive communications data. The RF Modulator Board (acting as an on-board Channel 3 Broadcast TV station) transmits video imagery to the SPS. The OOK system uses only the RF Modulator for Data and Video. In FSK systems, the LBV Data Board performs Data functions, while the RF Modulator (still present) only transmits Video.

Fiber Optic Video
Using the same OOK/FSK communication electronics, certain systems are equipped with a Fiber Optic Video transmitter/receiver set. The NTSC or PAL Composite video signal is taken directly from the Motherboard (bypassing the RF Modulator) and converted into a fiber optic signal via a transmitter integrated into the LBV-end of umbilical. It is sent over a multimode fiber optic line to a surface receiver, where it is reconverted and output as Composite video. It is used in special cases where:

-The user needs high-quality video that is not susceptible to RF interference, or;

-The user needs 200M of umbilical, while not incurring the added cost of fiber optic communication electronics.