User`s manual

26
this state as soon as it is switched on.
In remote control state, all keys and knobs become invalid (except “2nd” and
“Local” keys). When the power supply receives the remote command (SYST:REM)
through RS232 Interface or commands through GPIB Interface, REM annunciator will
be on and remote control becomes valid. In remote control state, all operations of the
power source are controlled by remote controller. After receiving the command
demanding the power supply to return to local control (eg. SYST:LOC ), the power
supply will go back to local control state and REM annunciator will be off. In remote
control state, the power supply can be returned to local control state by pressing “2nd”
+“Local” keys even if it has not received the returning command.
3.9 Protection Function
There are two protections states: over-voltage protection and over-temperature
protection for 3662A. Once anything abnormal is detected, the corresponding state
symbol in the State Register will be set; the power supply will disable its output and
beep to give an alarm; the display reveals the reason for the unusual condition and the
power supply enters into abnormal latched state. Except specific operations, the
supply will stop responding to other commands. For example: when the temperature
is too high, supply output will turn off and beep to give an alarm. OT will be showed
in the lower right corner of the display and the power supply will not respond to other
commands.
3.9.1 Abnormal Latched State Clearance
When the power supply enters into abnormal latched state, it fails to respond to other
commands. Only when the abnormal latched state is cleared by pressing “2nd” +
“Clear” keys, can normal operations be restored. Obviously, the reason for the
abnormal latch must be solved, or the power supply will enter into abnormal latched
state once again immediately.
3.9.2 Over-Voltage
The user can set the over-voltage protection value (Voltage Over) in the menu as
needed. When supply output voltage is higher than the set value, the system enters
into over-voltage protection status and the display shows OV. This state can be cleared
by decreasing the output voltage or increasing the over-voltage protection value.
Otherwise, even though you can remove the latched state by pressing “2nd” + “Clear”
keys, the system will automatically enter over-voltage protection status once again for
over-voltage.
3.9.3 Over-Temperature
If the internal temperature of the supply is above the safety limitation,
over-temperature protection will be triggered; the supply output will turn off and OT
is displayed. In the meantime, OT and PS in the Questionable Status Register will be
set and keep in this state until they are reset and over-temperature state is removed.
You can’t clear the abnormal latched state until the supply temperature falls to its