Theory of Operation
Power System
A 250 W power sup
ply generates a switched 12 volt bulk supply as well as a
5 volt standby supply.
No switch comp
letely disconnects t he line power from the instrument. The power
switch controls the power to the instrument through the COM-E board circuitry.
When the instrument is in the "power off" condition, there is still a low power
standby circuit to allow the system to monitor the power switch.
Fans
There are two instrument fans: the sys tem fan, which is mounted on the rear
chassis, and a smaller fan, which is mounted on the COM-E module. For cooling,
the system fan draws air into the instrumen t, for a positively pressured instrument.
ThesystemfaniscontrolledbyanembeddedprocessorontheMainboardandis
regulated by monitoring the temperature of the Analog acquisition board circuitry.
Cooling
air enters the instrument through speci fic locations on the covers, where
it flows directly over the heat s inks of each high wattage component. The COM-E
fan cools the COM-E m odule.
2–12 MSO70000/C, DSA70000B/C, DPO70000B/C, DPO7000, MSO5000, DPO5000 Series