Rockwell Automation PDC24 / PAC Chassis Power Supplies - Manual (Page 12)

12 PDC24 / PAC October 2005 – Issue 3
Triguard SC300E
Front panel LEDs
Check that the green LED (Normal) is on and the red LED (Fault) is off. A fault condition can
be due to:
• A failure of the ac/dc input supply
• An output below 5.1V
• An SMPS over temperature condition.
Check that the yellow LED (Power Share) is on. It extinguishes when the other PSU is
supplying the greater current.
If the Power Share LED is extinguished and no fault is indicated on either PSU, there could be an
imbalance in output between the two PSUs.
CALIBRATION
Calibration is not required in normal operation.
Calibration of PSUs must not be performed on a running system.
Use the front panel trimmers to adjust the balance until both Power Share LEDs are
illuminated. The voltage between pins 6 and 7 of both test sockets will be the same if the
PSUs are power sharing to any extent. If this voltage is being measured while adjusting a
trimmer, the other PSU will need to be switched off (or short circuit pins 1 and 5 of one test
socket to disable current sharing) to see any effect on the meter. Adjust both PSUs until the
voltage is the same (normally 5.4V ± 0.01V).