VIA Technologies EPIA SN-Series Specifications download pdf (Page 80)

FASTER Engineering Model

modified, C++ based remote camera control software available from the Canon SDK

support.

6.2 Power Subsystem

As shown in Figure 51, the FASTER EM power subsystem includes the M2-ATX-

140W automotive power supply, the 12 to 8 V DC-DC converter and the 12 Ah-12V lead

battery. The power supply covers a wide range of input voltages, 6 to 32 V and provides

the standard outputs for digital electronics: +3.3, +5, +5

, and ±12 V with maximum

current values reported in Table 8.

A standard 24-wire ATX power cable is used to power the EPIA EN15000 but only a

2-wire 5 V cable is needed by the PC/104 [Ref. (44)]. All other devices are powered using

the 12 V bus while for the Canon EOS has been necessary to develop a custom DC-DC

converter in order to guarantee the same Li-Ion battery voltage (8 V, slightly higher with

respect the nominal value of 7.4 V).

Maximum Power Characteristics

Output [V]

Current (max continuative) [A]

Current Peak (< 60 s) [A]

3.3

1.5

Table 8: M2-ATX-140W maximum power characteristics

A lead acid battery has been selected because of its simple recharge circuit, which

does not require special precautions, although Pb batteries have the lowest energy density

(30-40 Wh/Kg) and a modest cycle durability (500-800 cycles). The FASTER EM can

also be powered via a standard laboratory power supply or, if available, connected

directly to a 12 V stabilized power source onboard the aircraft, bypassing the battery.

Power consumption has been measured for each component using an amperometer

connected to the M2-ATX power supply, so currents are so referred to the 12 V bus.

Results are shown in Table 9, the computed battery duration is about 2 hours and 40

minutes which is slightly better of what experienced during test campaigns. This is

probably due to the cpu load variation of the EPIA EN15000 which has a maximum

power consumption of about 50 W at full load.

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VIA Technologies EPIA SN-Series Specifications Page 80