Performance Under Pressure
Off-the-shelf SNAP PAC System controls DEEPSEA CHALLENGER for James Cameron's historic dive
Photo by Charlie Arneson/National Geographic
On March 26, 2012, filmmaker and National Geographic Explorer-in-Residence James Cameron piloted a one-man submersible almost 7 miles (11 km) to the deepest point in the world's oceans.
Cameron's dive drew worldwide attention to the DEEPSEA CHALLENGE expedition, a joint scientific partnership by Cameron, National Geographic, and Rolex to research and explore the ocean's depths.
Cameron reached the sea floor in the DEEPSEA CHALLENGER, a technologically advanced submersible built by Sydney, Australia-based Acheron Project Pty. Ltd. (Image at right courtesy of Acheron.)
The sub's unique design and special materials are essential to withstand the extreme temperatures and pressures at full ocean depth, provide mobility, and keep the pilot safe.
But at the heart of the submersible, inside the 43-in. (109 cm) diameter pilot sphere, an off-the-shelf Opto 22 SNAP PAC System controls and monitors more than 180 onboard systems—including depth sensors, batteries, thrusters, life support, 3D cameras, and lighting.
Photo by Mark Thiessen/National Geographic
The PAC in the Sub
The SNAP PAC System constantly monitors sub status—for example battery power and oxygen levels—and reports results to the pilot on a color touch-screen display just inches from his head. The system also reads the pilot's joysticks to control the thrusters that propel and position the sub, and the robotic arms that collect samples and focus the underwater cameras.
Image courtesy of Acheron Project Pty Ltd
The SNAP PAC System used in the sub is the same standard product used in a wide variety of applications worldwide. The system includes a SNAP-PAC-S2 programmable automation controller, a rack-mounted I/O processor, and analog, serial, and high-density digital I/O modules. The PAC Project Professional Software Suite was used for control programming and HMI development and runtime.
The SNAP-PAC-S2 controller was chosen primarily for its communications flexibility and speed. With its two independent Ethernet network interfaces and four individually configurable serial ports (RS-232, RS-485 2-wire or 4-wire), the PAC-S2 easily handles communication with the wide variety of devices and systems onboard.
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