Advanced Personnel Environmental Controller System (APECS™)
The APECS™ family of electronics is used to support ISC closed circuit rebreathing systems. The APECS™ has been in the field for 10 years and is FCC approved and tested the stringent EN 61000 standard. The APECS™ system is designed to be used in a variety of roles to fit the operational needs of the customer. The APECS™ system is used in some of the most challenging places on Earth, with cave exploration at the top of the list. Cave divers using the APECS™ system to explore over 2 miles/3.2km through the earth and as deep as 700ffw/212mfw for hours at a time depend on the proven system with their lives, as the option of a safe and fast exit is not possible if a critical failure of the electronics is experienced. Other diving operations that the APECS™ are designed to operate in are: saturation operations, scientific, military, recreational, and other roles relating to deeper exploration diving. The APECS electronics has been tested to extreme temperatures down to 28° F/-2.22° C and the set point maintained perfectly at tested depths deeper than 330fsw/100 msw. APECS™ electronics provide the operational user the flexibility of conducting a greater operational role from one package, thus decreasing operational costs and inventory. Please see attachments for feature list and operational description.
APECS™ System Design Description
The Meg electronics supports 2 truly independent electronic oxygen monitoring systems with 2 independent displays telling the diver what they are breathing at all times. A failure of one system will not affect the other as there is no commonality between the 2 systems; this includes the operation of the automatic oxygen injection system. The system brain operates the oxygen injection system independent of the primary display, but the primary display adjusts set points and indicates PO2 and system status for the system brain. The secondary offers only monitoring and the diver’s heads up display (HUD). Each system has its own voting logic for oxygen cell monitoring. The brains of the oxygen injection, primary display and the secondary monitoring system is protected in a soft potted machined enclosure and further protected inside a ¼ inch thick 6061 T-6 anodized aluminum housing and they are independent from the handsets that only display the data to the diver. The brains of the system being isolated from the two displays protects it from failure as the Meg’s electronics can have both displays flood and the oxygen injection system will not be effected nor will the HUD as it will still operate offering the diver all 3 oxygen cell data. ISC does not believe the CCR systems controllers should be in the handsets as this does not provide adequate electronic system redundancy. The electronics system also can display full time to the diver the electrical output of the oxygen sensors, showing real time data to the diver and the diver can actually dive the system that way instead of the displayed PO2. This method does not require system calibration like the displayed PO2 on the displays. The voting logic is another unique system that each redundant electronic system shares. A sensor or sensors can be voted out if outside parameters. The system can actually maintain the oxygen set point off of one good sensor and this is confirmed by the diver using the displayed millivolt (mV) output on the system monitor page on both handsets. The advanced design of the APECS platform allows for customization of the electronics to meet the customer’s needs such as the APECS electronic cards can be swapped to different sides if the diver wants to have the primary display on the right wrist. With that being the simplest modification, the most extreme is to have two independent solenoids operated by two independent oxygen injection systems and displays. The diver can have the ultimate system. The APECS even allows for ISC approved dive computers to be added to the system for onboard decompression monitoring. Other systems such as the manual oxygen injection and diluent injections systems are either lung demand or physical push button and they may be used by the diver at anytime to over ride the electronics if a too high or too low oxygen condition exists.
Each system has its own remote power supply with its own power switch that cannot be turned off during the dive operation. The primary and secondary being independent are also designed with a disparity in power requirements from each other. The primary system has duration of over 70 hours if the solenoid was continuously injecting. The primary system will indicate a low power to the diver and keep driving the oxygen injector. If the diver ignores the alarm and power indicator for another 10 hours then the handset may blink on and off during the injection cycle and the diver can still see his displayed information and the O2 injector will still inject. The unit if still ignored, again for 10 hours will have the display fade out forcing the diver to observe the HUD or the secondary system. Oxygen will at some point not be injected when the battery has reached its threshold.
The secondary can last for over 200 hours as it does not drive any injection system but only displays the oxygen data and drives the HUD. This convention follows the methodology of the MK-16 eCCR system used by modern militaries.
The above system can use 3 different power supplies; 5 alkaline AA wired in series. A nine volt battery with an adapter plug for the connector, or two lithium C cells wired in series. Each battery has its own low battery characteristics and must be monitored appropriately.