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Page 18 of 32
100 kHz. Images for droop of internal capacitor storage can be seen at the end of the document. If the user
attempts to trigger the NSP at too high of a frequency, the internal control system will detect this and
disable the output, lighting the “Fault” LED. To re-enable the output, cycle the “HV Output” switch off
and then back on.
To provide noise immunity and safety, the external control input is fiber-optically coupled. EHT provides
a fiber optic driver (FT-1) that is used to send the appropriate pulses to the NSP. See additional
information about the FT-1 in section 7. Each rising edge of a signal going into the FT-1 will correspond
to a single output pulse of the NSP. The width of the pulse going into the FT-1 is not relevant so long as it
is longer than the minimum needed to trigger the FT-1
. EHT recommends using a pulse width in the
range of 500 ns to trigger the FT-1 for Triggered Mode Operation of the NSP
.
1.
Adjust the pulse width and voltage as described for Free-Running Mode, and freely trigger the
NSP using an external control system or signal generator through the FT-1.
6.6
External Mode Operation (Optional)
As an optional feature, the NSP can be operated in
External Mode
, triggered by a user’s own control
system or signal generator. Like the Triggered Mode, this allows for precision timing control, and allows
the NSP to be synchronized with other events in the user’s experiment as well as pre-defined bursts of
shots. Additionally, External Mode also allows the pulse width to be controlled remotely. This can be
useful if the user has a system which requires pulse width modulation, or otherwise wants to control the
pulse width remotely using their control system. The voltage is still controlled by the front panel knobs.
To operate in External Mode, set the Internal/External switch to the “External” position.
External Mode operation still restricts the user to the same range of pulse widths and frequencies that are
available in Free-Running Mode. Pulses that are too short will be automatically lengthened to the
minimum pulse width. Pulses that are too long will be automatically shortened to the maximum pulse
width. And pulses that come in at too high of a frequency will trigger a fault, shutting off the output. This
fault can be reset by lowering the external input frequency and then cycling the
HV Output Switch
on
the NSP front panel.
As with Triggered Mode, to provide noise immunity and safety, the external control input is fiber-
optically coupled. EHT provides a fiber optic driver that is used to send the appropriate pulses to the NSP.
See additional information about the FT-1 in section 7. Each rising edge of a signal going into the FT-1
will correspond to a single output pulse of the NSP.
The input pulse width given to the FT-1 does not map directly to the high voltage output pulse width, and
the scaling is nonlinear. The user will need to measure their output waveform to dial in a particular pulse
width. Figure 9 shows the nominal mapping between the input pulse width and the output pulse width, as
measured into a resistive load.
1.
Set the voltage using the front panel knobs, and freely trigger the NSP using an external control
system or signal generator through the FT-1.
Summary of Contents for NSP Series
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