Chapter 3 Front-Panel Operation and Features
Disabling the Output
54

Disabling the Output

The output of the power supply can be disabled or enabled from the front panel.
• When the power supply is in the “Off” state, the OFF annunciator turns on
and the output is disabled. The OFF annunciator turns off when the power
supply returns to the “On” state. When the output is disabled, the voltage
value is 0 volts and the current value is 0.02 amps. This gives a zero output
voltage without actually disconnecting the output.
• The output state is stored in volatile memory; the output is always disabled
when power has been off or after a remote interface reset.
• While the output is disabled, the control knob is locked to prevent from any
unwanted changes occurring. But the other front panel keys are working.
• To lock the control knob, move the flashing digit to the right or left using
or resolution selection keys until the flashing digit disappears.
To see or check the changes while the output is disabled, press before
returning to meter mode.
• Front-panel operation:
output Off
• Remote interface operation:
OUTP {OFF|ON}

Disconnecting the Output Using an External Relay

To disconnect the output, an external relay must be connected between the
output and the load. A TTL signal of either low true or high true is provided to
control an external relay. This signal can only be controlled with the remote
command OUTPut:RELay {OFF|ON}. The TTL output is available on the RS-
232 connection pin 1 and pin 0.
When the OUTPut:RELay state is “ON”, the TTL output of pin 1 is high
(4.5 V) and pin 9 is low (0.5 V). The levels are reversed when the
OUTPut:RELay
state is “OFF”. The TTL output of pin 1 or pin 9 of the RS-232
connector is available only after installing two jumpers (JP102 and JP103)
inside the power supply. See the Service Information to locate them.
Note Do not use the RS-232 interface if you have configured the power supply to output
relay control signals. Internal components on the RS-232 circuitry may be damaged.
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Display
Limit
On/Off
Output