Service manual
62 E8408A Product Specifications Appendix A
Electromagnetic
Compliance/Safety
Specifications
The E8408A mainframe conforms to the EMC and safety product
specifications listed in the Declaration of Conformity (see Page 7).
EMC performance can be further enhanced with the following shields:
• Front panel gasketing provided per VXI Rev. 2.0, B.7.2.3
• Backplane connector shields per VXI Rev 2.0, B.7.2.3
• Intermodule chassis shields per VXI Rev 2.0, B.7.3.4
Power Supply
Protection
The supply is protected from over-temperature, over-voltage, short-to-
ground, and short-to-other output. Protection modes vary, from removing
the fault condition to cycling the power on/standby switch to removing and
reconnecting AC power.
Over-Temperature
Protection
The front panel Temp (temperature) indicator flashes when an internal
temperature is high enough to cause the mainframe to approach thermal
shutdown, but the Temp indicator does not cause shutdown. When thermal
shutdown limit is reached, all supplies are automatically turned off.
Recovery occurs automatically when the mainframe has cooled sufficiently.
Over-Voltage Protection Over-voltage will generally cause a global shutdown, and recovery occurs
when the Power On/Standby switch is cycled. However, some over-
voltage conditions on the +5V and +12V can cause a shutdown that will not
respond by cycling the Power On/Standby switch. In this case, the Power
On/Standby switch should be placed in Standby position and AC power
must be removed and reapplied before the mainframe will turn on again.
Short-to-Ground
Protection
Short circuit behavior varies with the specific supply, but (in general)
recovery should occur when the short is removed. This table summarizes
short-circuit behavior for each supply voltage.
Supply
Shorted
Short-Circuit Behavior
+5V or
+12V
Causes global shutdown. After about 250 msec, the supplies
will automatically attempt to turn on. Global shutdown and
restart attempts will continue until the fault is removed.
+24V Puts supply in foldback current limiting mode.
-24V Puts supply in foldback current limiting mode, and shuts
down the -12V, -5.2V, and -2V supplies.
-12V Continuously draws about 7 Amps and shuts down the -5.2V
and -2V supplies.
-5.2V Continuously draws about 7 Amps (Standard).
-5.2V Continuously draws about 12 Amps (Option 001).
-2V Continuously draws about 5 Amps.