VIA Technologies EPIA SN-Series Specifications download pdf (Page 114)

Results of the test campaigns

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The problem was corrected applying a files check routine which changes the file name if

it already contains data. This action was taken because it had been verified that when the

battery is almost discharged, small voltage variations can cause some systems to restart

before the full discharge of the battery.

Acquisition tests were conducted on the NAV420 and GPS receiver units, verifying

expected data exchange rate. NAV420 magnetometers calibration procedure was applied

before and after the installation inside the airborne internal management and computing

rack box. Being the NAV420 installed near other electronics devices (as shown in Figure

66) the magnetic field was also measured during system operations with minor changes.

Tests on the GPS signal demonstrate that image acquisition was correctly enabled

only if a valid GPS sentence is received and the camera arm switch is on the enable

position. Ethernet connections were tested too; UDP packets are sent from the Advantech

PC/104+ board (IP address 192.168.1.100) only to the EPIA EN15000 board (IP address

192.168.1.218) and data is displayed by the FASTER system monitor and represented in

the virtual tunnel application.

Some minor issues were encountered in the power subsystem when using an external

power source. As reported in Table 9, some devices have a current drain peak during

startup phase that can cause the system to restart if the power supply is unable to deliver

an adequate power level. To avoid restarts an appropriate startup sequence was defined

which consists in startup the system with the LCD screen and the camera powered off in

order to manage the EPIA EN15000 startup power absorption peak. Once the system is

ready and in all the peripherals are in idle mode, the Canon camera is powered firstly,

because it also has an absorption peak during startup phase because all the internal

subsystem are checked (camera screen, shutter and secure digital read/write operations

are performed); then the LCD screen is powered up.

The entire system was subjected to long run tests, in order to verify the perfect

matching between the number of acquired images and their ancillary information,

contained in the log file provided by the PC/104+ board. This was needed because

sometimes, during high system loads, the insufficient data rate may cause the camera

memory buffer (32 Mbytes, corresponding to approximately 3 RAW images) to be filled

up, preventing the acquisition of additional images. In this case there is no longer

matching between the image number and the log number since there is no real-time

feedback on the camera shoot signal.

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VIA Technologies EPIA SN-Series Specifications Page 114