37
5.10. PS_OK SIGNAL
PS_OK signal indicates fault condition in the power supply. PS_OK is a TTL signal output at J1-16,
referenced to IF_COM at J1-2, 3 (Isolated Interface Common)). When a fault condition occurs, PS_OK
level is low, with maximum sink current of 1mA, when no fault condition occurs, PS_OK level is high
with maximum source current of 2mA. The following faults will set the PS_OK to Fault state:
*OTP *Enable/Disable open
*OVP *SO (Rear panel Shut-Off)
*Foldback *IEEE failure (with optional IEEE interface)
*AC fail *Output Off
4.11. SAFE START AND AUTO-RESTART MODES
When turning on the power supply AC On/Off, it can start to its last setting of Output Voltage and
Current limit with the output enabled (Auto-restart) or start with the output disabled (Safe mode).
Press and hold the OUTPUT button to select between Safe start and Auto-restart modes. The
VOLTAGE display will continuously cycle between "SAF" and "AUT" every 3 seconds. Releasing
OUTPUT pushbutton while one of the modes is displayed, selects that mode. The default setting at
shipment is Safe mode.
5.11.1Automatic start mode
In this mode, the power supply restores its last operation setting. Upon start-up, the output is
enabled or disabled according to its last setting. Confirm its last output setting before AC turn-on
again.
5.11.2 Safe start mode
In this mode, the power supply restores its last operation setting and sets the Output to off state.
At start-up, the output is disabled and the output voltage and current are zero. To enable the
output and restore the last output voltage and current limit values, momentarily press OUTPUT
button.
4.12. OVER TEMPERATURE PROTECTION (OTP)
The OTP circuit shuts down the power supply before the internal components can exceed their safe
internal operating temperature. When an OTP shutdown occurs, the display shows "OTP" and the
ALARM LED blinks. Resetting the OTP circuit can be automatic (non-latched) or manual (latched)
depending on the Safe or Automatic restart mode.
1. Safe start mode: In Safe start mode, the power supply stays off after the over temperature
condition has been removed. The display continue to shows "OTP" and the ALARM LED continues
to blink. To reset the OTP circuit, press OUTPUT button (or send OUT ON command via the serial
port).
2. Auto-restart mode: In Auto-restart mode, the power supply recovers to it's last setting
automatically when the over temperature condition is removed.
To Next Page
