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8 - Manual setup
Output Off state
60
SMU4000 Series Instruction Manual
Output Off state
CNFG >
[Source Measure Action] Manual Setup
>
[Source] Off State
The off-state configuration determines the state of the source and terminals when the output is
disabled.
Even when the output is disabled, this does not guarantee that the instrument is fully isolated
from the external circuitry.
If any trip condition occurs, the instrument goes straight into the Open output off state.
By default, no measurements are stored in the results buffer whilst in an off condition; the
measurement buffer will only be populated whilst the output is running. During the off
condition the measurement buffer will be populated with the results from the last time the
output was run.
If measurements are required whilst the output is off, this can be set using the Measurement
button in the Output off State menu, see ‘
NOTE
Off state measurements will never appear in the results buffer. They will appear on the home
screen in the results box, or can be queried via SCPI remote command.
NOTE
The output off state will be applied to the selected operating mode, changing the mode of
operation may also change the output off state.
Not all off states are available in each mode.
There are a total of 4 output off states that can be chosen from –
Open
- This is the only output state that completely isolates the external circuitry from the
instrument. In this state all of the terminals are made open circuit and no terminals are
monitored.
It is important to note that selecting Open as the off state does add a small delay to the output
response time for the guaranteed opening and closing of relays.
This is dealt with automatically without the need to set a measurement delay. To help prolong
the life of the relay, avoid using the Open off state when frequent enabling and disabling of the
output is required.
Hi Z
- This is a high impedance state where effectively SC mode is engaged, and the source
current is set to 0.0nA. For modes that have a voltage limit (SC and MR) the voltage limit is set
to the user defined limit setting. For all other modes the voltage limit is set to the maximum
allowable voltage given the status of the HV interlock, or the maximum allowable voltage for the
SMU4001. Note that when the terminals are left open circuit the voltage may drift around
significantly due to the very high input impedance.