User`s guide

4 Operating the Power System
88 Series N6700 User’s Guide
Front Panel: SCPI Command:
Select Protect\OVP.
Enter a value in the OVP level box
and press Select.
For J01 units, enter a value in the
Tracking OVP Offset box and check
the Enable box. Then press Select.
To set an OVP of 10 V for output 1:
VOLT:PROT 10,(@1,2)
For Models N678xA SMU:
VOLT:PROT:REM 10,(@1,2)
To enable tracking OVP for output 1:
VOLT:PROT:TRAC ON,(@1)
To set the tracking offset for output 1:
VOLT:PROT:TRAC:OFFS 2,(@1)
Agilent Models N678xA SMU also have a back-up local OVP function.
Refer to “Over-voltage Protection” in chapter 2 for a description of
the feature. Additionally, for Agilent Model N6784A, you can program
a negative over-voltage value. Enter the value in the -OVP
field.
Set the Over-Current Protection
When over-current protection is enabled, the power system turns off
the output if the output current reaches the current limit setting and
transitions from CV to CC mode.
Front Panel: SCPI Command:
Select Protect\OCP.
Check Enable OCP and press Select.
To enable OCP for outputs 1 and 2:
CURR:PROT:STAT 1,(@1,2)
You can also specify an OCP delay to prevent momentary CV-to-CC
status changes from tripping the over-current protection. The power
system may momentarily transition into CC mode when it is turned
on, when an output value is programmed, or when the output load is
connected. In most cases these temporary conditions would not be
considered an over-current protection fault, and having an OCP
condition disable the output when the CC status bit is set would be a
nuisance. Specifying an OCP delay lets the OCP circuit ignore the CC
status bit during the specified delay period. Once the OCP delay time
has expired and if the CC mode persists, the output will shut down.
The delay can be programmed from 0 to 0.255 seconds. You can
specify if the OCP delay timer is started by any transition of the
output into CC mode, or only at the end of a settings change in
voltage, current, or output state.
Front Panel: SCPI Command:
Select Protect\OCP.
Enter a delay value and press Select.
Check "Start delay on CC" to start the
delay timer by ANY output transition
into CC mode. Otherwise, the delay
timer will only be started by a settings
change in voltage, current, or output
state.
To specify a 10 millisecond delay:
OUTP:PROT:DEL 0.01,(@1)
To start the delay timer by ANY output
transition into CC mode:
CURR:PROT:DEL:STAR CCTR, (@1)
To start the delay timer by a settings
change in voltage current or output:
CURR:PROT:DEL:STAR SCH, (@1)