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Compact embedded PC offers expansion modules via serial pass-through

Nov 3, 2011 — by Eric Brown — from the LinuxDevices Archive — views

Sealevel announced a fanless, rugged embedded computer with an RS-422/485 pass-through port that supports the company's N-series SeaI/O expansion modules. The Relio R1420 is equipped with 2GB of DDR2 RAM, a CompactFlash slot and an optional SSD (solid state disk), dual gigabit Ethernet ports, four serial ports, six USB 2.0 ports, and 8-bit GPIO.

The Relio R1420 is designed for harsh industrial and commercial environments, and can be used for embedded control and test and measurement, says Liberty, South Carolina based Sealevel. The Linux- and Windows-ready device follows a long line of Relio-branded industrial computers, such as last year's high-end Intel Core 2 Duo-based Relio R5200.

Relio R1420

(Click to enlarge)

In addition to the Relio R5000 series of Core 2 Duo systems, Sealevel fields various rack-mounted systems, including the Pentium- and Celeron-based Relio R3000 and R4000 series. There's also an R2000 series of configurable box computers, first announced back in 2006, offering those same two Intel processors.

The Relio R1420 is the newest member of the R1000 series of compact computers, which includes four models based on the AMD Geode LX800 processor. The R1420 moves up to the 1.6GHz Intel Atom N450, housed here on a 3.5-inch single board computer (SBC) along with 2GB of DDR2 667MHz RAM. The N450 was one of the first "Pineview" Atoms with on-chip graphics, capable of displaying 1400 x 1050 resolution on the R1420, according to Sealevel.

The R1420 is further equipped with 2GB of flash storage, as well as a CompactFlash socket. There's also a 2.5-inch SATA bay for an optional solid state drive (SSD), says Sealevel. Both are protected behind faceplates, but easily accessible, says the company.

A 2.5-inch SATA bay supports an optional SSD.

I/O is divied up between the front and left side of the 7.5 x 5.1 x 1.8-inch box, pictured earlier in this story, while the right side (above) houses the drive bay. Dual gigabit Ethernet ports are provided, as well as six USB 2.0 ports, with four of them said to offer high-retention connectors. Also available are an external 8-bit GPIO terminal block, audio output, and a VGA port.

The Relio R1420 is equipped with three RS-232 serial ports with DB9M connections, as well as an RS-422/485 port with termination and biasing dipswitches. The RS-422/485 COM2 connection is available via a choice of a DB9M port, removable terminal blocks, and an RJ45 port that acts as a Modbus RTU RS-485 pass-through port (see image below).

The RJ45 port supports Sealevel's N-series SeaI/O expansion modules, which include optically isolated inputs, Reed and Form C relay outputs, TTL interfaces, and A/D and D/A modules.

Left side of R1420 showing multiple RS-422/485 connection options

(Click to enlarge)

The R1420 is powered from a 9-30VDC source, offers optional power supply choices, and runs on a maximum of 30 Watts, says Sealevel. Housed in a rugged metal enclosure, the R1420 offers optional mounting for walls, under counters, or even to DIN rails, says the company. Extended temperature motherboards, hard disk drives, and other options are said to be available on request.

Features and specifications listed for the Relio R1420 include:

  • Processor — Intel Atom N450 @ 1.6GHz
  • Chipset — Intel ICH8M
  • Memory — 2GB of DDR2 667MHz RAM (max.); 2GB flash
  • Storage expansion — CompactFlash Type II (accessible via removable plate); 2.5-inch drive bay with optional SSD (via thumbscrews)
  • Networking — 2 x gigabit Ethernet ports
  • Other I/O:
    • 6 x USB 2.0 ports (4 x with "high-retention connectors")
    • 3 x RS232 ports
    • RS-422/485 (COM2) via a DB9M port, removable terminal blocks, or an RJ45 pass-through port with Modbus RTU support
    • 8-bit GPIO via 10-position removable terminal block
    • VGA port
    • audio out jack
  • Other features — watchdog; APM and ACPI power management; LEDs; recessed reset switch; optional SeaI/O expansion modules via RS-422/485
  • Power — 9-30 VDC @ 15W nominal (30 W max.); optional power supplies available; battery backup (3V/210mAH)
  • Operating temperature — 32 to 122 deg. F (0 to 50 deg. C); extended temp. support available upon request
  • Dimensions — 7.5 x 5.1 x 1.8 inches
  • Weight — approx. 3 lbs


The Relio R1420 is available now at prices starting at $999, says Sealevel. The system supports Linux, as well as 32-bit and 64-bit versions of Windows 7 Professional. More information may be found at Sealevel's Relio R1420 product page, and more on other Relio computers may be found on the company's industrial computer page.

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