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5.5.1 Setting the Foldback protection
To arm the Foldback protection, the FOLD button should be pressed so that the FOLD LED
illuminates. In this condition, transition from Constant Voltage to Constant Current mode will
activate the Foldback protection. Activation of the Foldback protection disables the power supply
output, causes the ALARM LED to blink and display " Fb " on the VOLTAGE meter.
5.5.2 Resetting activated Foldback protection
There are four methods to reset an activated Foldback protection.
1. Press the OUTPUT button. The power supply output is enabled and the Output Voltage and
current will return to their last setting. In this method, the Foldback protection remains armed,
therefore if the load current is higher than the current limit setting, the Foldback protection will
be activated again.
2. Press the FOLD button to cancel the Foldback protection. The power supply output will be
disabled and the VOLTAGE display will show “OFF”. Press the OUTPUT button to enable the
power supply output.
3. Turn the power supply output Off and then On using the SO control (refer to sect. 5.7). In this
method the Foldback protection remains armed, therefore if the load current is higher than the
current limit setting the Foldback protection will be activated.
4. Turn the power supply Off using the AC On/Off switch, wait until the front panel display turns Off,
then turn the unit back ON again. The power supply output is enabled and the Output Voltage
and Current will return to their last setting. In this method, the Foldback protection remains
armed, therefore if the load current is higher than the current limit setting, the Foldback
protection will be activated again.
4.6. OUTPUT ON/OFF CONTROL
The Output On/Off enables or disables the power supply output. Use this function to make
adjustments to either the power supply or the load without shutting off the AC power. The Output
On/Off can be activated from the front panel using the OUTPUT button or from the rear panel J1
connector. The OUTPUT button can be pressed at any time to enable or disable the power supply
output. When the output is disabled, the output voltage and current fall to zero and the VOLTAGE
display shows “OFF”.
4.7. OUTPUT SHUT-OFF (SO) CONTROL VIA REAR PANEL J1 CONNECTOR
Contacts 2, 3 and 15 of J1 (Fig.4-2, Item 5) serve as Output Shut-Off (SO) terminals. The SO
terminals accept a 2.5V to 15V signal or Open-Short contact to shut off the power supply output. To
rise the output again after shut-off, apply the reverse-logic signal (Table 5-2) to the SO terminals. In
Auto-Restart mode the output will re-rise automatically after reset the SO control, but in safe start
mode pushing OUTPUT button is needed to raise the output again after reset
NOTE: Set the output-on to start the SO control. Under output-off condition, this function is not
active.
This function is useful for connecting power supplies in a “Daisy-chain” (refer to section 5.16). The
SO control can be used also to reset the OVP and Fold Protection. Refer to sect. 5.3 and 5.5 for
details. When the unit is shut-off by J1 signal, the VOLTAGE display will show “SO” to indicate the
unit state. J1 contact 15 is the SO signal input and contacts 2 and 3, IF_COM, are the signal return
(connected internally). Contacts 2, 3 and 15 are optically isolated from the power supply output. The
SO control logic can be selected by the rear panel SW1 Setup switch. Refer to Table 5-2 for SW1
setting and SO control logic.
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