User Documentation
252661740000/01/06-2020
Measuring
Measuring
Auto / Manual measurement mode
Measurements of surge protective components (SPCs) or surge protective devices (SPDs) can be
performed in one of two ways with this instrument – using the auto mode or using the manual mode. The
auto mode is selected by clicking the AUTO button on the button panel.
When in auto mode the instrument attempts to carry out an auto-detection of the type of SPC or SPD
connected, and congures itself to measure such device accordingly.
If a GDT component (voltage-switching device) is detected, it will congure itself into the voltage ramp
mode. The measurement is performed by ramping the voltage across the component until it res (also
known as avalanche, breakdown, spark-over or crowbar). The peak voltage reached before breakdown is
displayed on the output panel. The rate of voltage ramp applied is setup in the Measure Setup menu (refer
to Measurement screen section).
• During measurement unit has to be disconnected from any power supply. Protective device
must also be disconnected from power supply and must not be grounded.
• During measurement of the protective device, USB port must not be used.
If an MOV or TVS component (voltage-limiting device) is detected, it will congure itself into the constant
current mode. The measurement is performed by driving a xed constant current through the device and
recording what voltage appears across the device (often referred to as the clamping voltage). The clamping
voltage is displayed on the output panel. The constant current applied is setup in the Measure Setup menu
(refer to Measurement screen section).
The manual mode allows the user to override auto-detection and specically select the type of component
or device being tested. This is done by clicking the MOV, GDT or TVS buttons on the button panel. The
selection is indicated by shading the relevant button orange.
In general, the auto mode is more convenient where the SPD consists of a single protection component,
or when multiple protection components of the same kind are used – for example, an SPD where the
internal protection components are all MOVs. When a mix of technologies is used, such as in a so-called
combination-type SPD where an MOV and GDT may be connected in series, it is generally better to use the
manual mode, thereby having control over the instrument to enforce either a constant current, or a voltage
ramp in performing the measurement.
In either manual mode or auto mode the instrument will display the unknown SPD Icon with either the
word ‘Open’ or ‘Short’ if it encounters either an open-circuit or short-circuit path respectively. Under such
condition, please check the lead set is correctly plugged into the instrument and connections to the device
or component under test is secure.