Introduction

Aitech’s E121 3/4-ATR Short air-cooled enclosure is built to be rugged and reliable as well as lightweight and compact. EMI/RFI protected and environmentally sealed, the E121 is capable of withstanding extreme environmental conditions of altitude, temperature, moisture, shock, vibration, EMI and chemical exposure, making it ideal for use in military and aerospace environments.

STURDY MECHANICAL DESIGN

The E121 is constructed of durable CNC machined 6061-T6 aluminium. Fasteners are stainless steel and removable cover threads have self-locking stainless steel helicoils to withstand severe vibration and shock. All I/O connectors are located on the front panel of the enclosure for easy access. The chassis is air-cooled. Designed with a built-in handle, the E121 is also equipped with two front mounting hooks and two rear hold-down pin receptacles to facilitate installation in standard ARINC 404 3/4-ATR mounting trays.

BOARD CAPACITY

The E121 accommodates 8 standard VMEbus boards with 0.8-inch pitch, including:

• 8 conduction-cooled cards (IEEE 1101.2 or VITA 30.1)
• 3/4-ATR conduction-cooled power supply

VMEBUS BACKPLANE

The backplane is VME64x compliant with 160-pin, 5-row J1/J2 DIN connectors and 95-pin P0 connectors in all slots.

Any of the pins in rows A and C and user-defined pins in rows Z and D of the J2 connectors as well as the 95 I/O pins from each of the P0 connectors (up to a maximum of 512) can be routed to front panel I/O connectors. DC input power is routed to the power supply via a separate screened harness so as to prevent radiated or conducted EMI.

FRONT PANEL

The front panel features a flexible configuration of user-defined 38999-style connectors that conform to military standards, one for input power and all others for I/O. It may also be equipped with any of the following options: elapsed-time meter, LED indicator to track system operation, On/Off switch and external grounding lug.