Figure 13. AC PSU status indicator
1 AC PSU status indicator/handle
Table 10. AC PSU status indicator codes
Power indicator codes Condition
Green A valid power source is connected to the PSU and the PSU is operational.
Blinking amber Indicates a problem with the PSU.
Not illuminated Power is not connected to the PSU.
Blinking green When the rmware of the PSU is being updated, the PSU handle blinks green.
CAUTION: Do not disconnect the power cord or unplug the PSU when updating rmware. If 
rmware update is interrupted, the PSUs do not function.
Blinking green and turns o When hot-plugging a PSU, the PSU handle blinks green ve times at a rate of 4 Hz and turns o. This 
indicates a PSU mismatch with respect to eciency, feature set, health status, or supported voltage.
CAUTION: If two PSUs are installed, both the PSUs must have the same type of label; for 
example, Extended Power Performance (EPP) label. Mixing PSUs from previous generations of 
PowerEdge servers is not supported, even if the PSUs have the same power rating. This results 
in a PSU mismatch condition or failure to turn the system on.
CAUTION: When correcting a PSU mismatch, replace only the PSU with the blinking indicator. 
Swapping the PSU to make a matched pair can result in an error condition and unexpected 
system shutdown. To change from a high output conguration to a low output conguration or 
vice versa, you must turn o the system.
CAUTION: AC PSUs support both 240 V and 120 V input voltages with the exception of Titanium 
PSUs, which support only 240 V. When two identical PSUs receive dierent input voltages, they 
can output dierent wattages, and trigger a mismatch.
CAUTION: If two PSUs are used, they must be of the same type and have the same maximum 
output power.
CAUTION: Combining AC and DC PSUs is not supported and triggers a mismatch.
Dell EMC PowerEdge R540 overview 19