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8 - Manual setup
Limits and Protection
65
SMU4000 Series Instruction Manual
Protection
There are three user settable digital protection limits:
·
Over Voltage protection
·
Over Current protection
·
Over Power protection
These can be applied to each mode of operation. These can be set to a specific level or set to
Disabled.
If set to disabled, the trips are set accordingly:
[SMU4201] Voltage HV = 220V , Voltage LV =44V [SMU4001] 22V
Current = 3.3A
Power = 27.5W
Each of these protection limits are continually checked against the raw measured Voltages and
Current and computed Power readings. The measurement period and delay have no effect on
the trip response.
The trip response time is typically <200µs, regardless of any user settings.
NOTE
OVP Trip protection is based on the voltage measurement which can be affected by the terminal
configuration.
NOTE
Trip protection applies to the mode of operation, when the mode is changed, the protection will
change to the settings in the selected mode.
There is also an integrated internal over temperature protection limit. The instrument can
overheat if the ambient temperature exceeds the recommended operating range limit stated in
the specification, or if the ventilation is restricted.
When these protection limits are exceeded, the output is tripped and the ‘off state’ is set to
OPEN, thus completely isolating the external circuitry from the instrument.
When tripped, a protection trip pop-up message is displayed and recorded in the ‘Event log’.
The protection trips are not latched, once the trip has occurred, the output can be re-enabled
but there’s no guarantee that the trip won’t happen again.
Whenever a temperature trip occurs, it is advised to leave the instrument to cool down before
re-enabling the output. It’s also worth investigating the potential cause of the temperature trip
to see if it can be alleviated by ensuring all ventilation is unrestricted.
If one of the voltage, current or power trips occurs unexpectedly, this may be a result of
instability, for information on how to overcome potential instability see ‘
.