This page is the user manual for the main tab of the user interface. For the waveform tab, refer to Custom waveform tab.
1. Main program Window

To take full advantage of the graphic user interface, a good understanding of the hvps-x hardware and related terminology is recommended. Refer to the hardware page for more information. The numbered section refer to the numbers shown on the image above.
-
- The switching mode parameter of the hvps-x is split into 2 buttons: a on/off button on the left, and a button on the right that cycles between the other modes. This enables to quickly switch between any active mode and ‘Off’ by toggling the on/off button, rather than having to cycle through every modes. The table below shows what is the effective switching mode as a function of the two button state:
Left button Right button Effective switching mode Off Low Off Off High Off Off Switching Off On Low Low On High High On Switching Switching
In other words, if the left button is ‘Off’, the switching mode is ‘Off”. If it is ‘On’, then the switching mode is whatever is shown on the second button. - The voltage set point can be set using the slider, or by typing a value in the entry box. To validate a new value typed in the entry box, you need to either click outside of the box or press enter.
- The frequency of the pulses (only effective when the switching mode is set to ‘switching’ or ‘waveform’) can be set with the slider or via the entry box. By default, the slider enables to set frequency values between 0.1 Hz and 10 Hz, but the entry box accepts the whole frequency range (0.001 Hz to 100 Hz). To validate a new value typed in the entry box, you need to either click outside of the box or press enter. Refer to Frequency capabilities for more detail on the frequency capabilities of the hvps-x with respect to the load connected to the output.
- The duty cycle of the pulses (only only effective when the switching mode is set to ‘switching’) can be set with the slider or via the entry box. When typing values in the entry box, the slider will change as you type (unlike voltage or frequency). Still, to validate a new value typed in the entry box, you need to either click outside of the box or press enter.
- This little graph inset shows the profile the output voltage once the output stage is enabled. The separation of the switching mode button in two buttons (see 1 above), makes it possible to prepare the output state of the hvps-x and visualise it before turning the output on. To attract the user’s attention to the fact that the settings from this graphical window are not applied to the output, the string ‘off’ is displayed at the centre of the graph when the switching mode (1) is set to off.
graphic user interface: visualisation of output wavform. Left: when button on/off is on position Off, the string ‘Off’ is shown at the centre of the waveform graph. The figure above shows a 2000V square signal at 2 Hz with a 10% duty cycle. On the left, the switching mode is ‘off’. The waveform is ready to be generated, but not yet applied to the output, as also shown by the “Off” text at the centre of the graph. On the right, the switching mode is ‘switching’ and the waveform is now applied to the output. The keyword ‘Off’ doesn’t appear on the graph.
- Selection of the switching source. Is is important to remember that if this is set to button, the selected switching mode in (1) will only be applied to the output when the on-board button is activated.
- Selects whether the high voltage DC-DC converter works in open loop or in closed loop (i.e. regulated). In open loop, the voltage set point doesn’t necessarily correspond to the the output voltage. When the load is small, it will be ~10% higher. Refer to the hardware page for more information.
- This is a graph of the hvps-x output. It is is updated every 500ms and the resolution is 10 pts/s (*). Two traces are shown: blue is the output of the DC-DC converter. In regulated mode, it should be equal (minus regulation error) to the voltage set point set in (2). Red is the output of the hvps-x, after the high-voltage switch.
(*): see also the Options section for explanations on the trace mode option.hvps-x in switching mode The image above shows the hvps-x in switching mode with a 3000 V square wave with a 33% duty cycle. The measured output of the DC-DC converter is stable at 3000 V, and the measured output of the hvps-x shows the expected waveform.
Due to the refresh speed of the display, it is mainly useful to monitor the output of the power supply in DC mode, or for a very slow waveform / square wave. For frequencies above 0.5 Hz, the trace mode, described in the Options section is more appropriate. - This button enables to check the value of some of the current setting’s parameters and to perform memory operation. Refer to the section below for more information.
- This button saves the active settings in memory. When the hvps-x is power-cycled, it loads its default operating parameters from memory.
- This button enables so set some GUI parameters Refer to the Options section below for more information.
- This button disconnects the hvps-x and closes the interface.
- The switching mode parameter of the hvps-x is split into 2 buttons: a on/off button on the left, and a button on the right that cycles between the other modes. This enables to quickly switch between any active mode and ‘Off’ by toggling the on/off button, rather than having to cycle through every modes. The table below shows what is the effective switching mode as a function of the two button state:
2. Dialog boxes
2.1 Memory & Memory operations
We recommend reading the memory & settings page to gain a good understanding on the different types of settings and the different ways to transfer settings from the memory to the RAM to be used by the firmware.
From the main tab of the graphic user interface, the memory operations are available by pressing the Memory button (9)

The dialog box contains 3 tabs. The general tabs showsthe main parameters from the current settings, which are loaded into RAM when the hvps-x is initialised. It includes functional parameters such as switching mode, voltage set point, switching mode, etc. It also displays the Hardware (PCB) and Firmware versions.
The Memory operations tab enables the manipulation of the settings. The desired operation(s) must be selected via the checkboxes, and the parameter for each operation are defined with the radio buttons:
- Load settings loads either sets of settings (current or backup) from memory to the RAM to be used immediately by the hvps-x
- Copy memory settings copies one set of settings to the other, overwriting the target. You can copy the current settings to the back-up settings and vice-versa.
- Dump to file writes either set of settings (or both) into a JSON file. The file will be created in the root directory of the interface and will include the name of the hvps-x, the type of settings, and a time stamp.
- Transfer from File uploads a setting file from the host to the hvps-x. The drop-down menu shows a list of valid setting files in the root folder of the UI.
Press OK to perform the action selected in the checkbox(es) or cancel to close the Dialog without taking action.
2.2 Options
From the graphic user interface, press button (11) to display the options dialog. Closing the dialog box with Ok applies the selecting settings, while closing it with Cancel or the X discards any modification.
2.2.1 Button Configuration section
Defines the behaviour of the on-board button S2 (refer to the hardware page for a detailed explanation of the Latching mode and the Off state). The button configuration is part of the hvps-x settings. Therefore, if you want the button settings to be remembered the next time the hvps-x initialises, use the save button (10) after modifying the parameters in the options dialog.
2.2.2 Graph Configuration section
Graph autoscale defines the scaling behaviour of the the voltage reading graph (8), as described above in the GUI main tab (section 1). Changing the autoscale setting in the dialog box is active until the interface is closed. If you want this change to be permanent when you close and restart the graphic user interface, edit the config.ini file.
When trace mode is not ticked, the output voltage graph is updated twice per second and displays 10 points/s. This works well to monitor the output when a constant voltage is applied, or for square waves, if the frequency is very slow (<0.5 Hz). However, the refresh rate is not fast enough to display meaningful information for waveforms of higher frequencies. This is well visible on the graph below with a 0.5 Hz square waveform correctly displayed on the live graph, but a 5 Hz waveform appearing to be erratic. At this frequency, the sampling rate of the graph is not fast enough to correctly display the output waveform.

When trace mode is ticked, the hvps-x records the output voltage in an internal 100-point buffer with a sampling period defined by the user. Once the buffer is full (but at most twice per second), the buffer is transmitted to the GUI and displayed at once on the graph. The minimum sampling period is 2 ms (sampling frequency of 500 Hz), which is much faster than the normal logging mode and hence makes it possible to capture faster changing signals. The disadvantage is that instead of having a graph that is continuously updated, with the older data disappearing on the left and the new data appearing on the right, the graph is updated by burst once the 100-buffer is full. The image below shows the same 5Hz signal as in the previous figure, but displayed in burst mode:

When trace mode is ticked, two other options are available (they are ignored when trace mode is not ticked):
- sampling period: the time between sampling points in ms (integer values). The minimum is 2. As the buffer contains 100 points the graph refreshes every 100 x sampling period (i.e. if sampling period is 20 ms, the graph will refresh every 2 s). There is a minimum refresh time of 500 ms, which means that for sampling periods between 2 and 5, the refresh rate is 500 ms.
- Auto period: If this is ticked, the sampling period parameter above is ignored and is calculated by the hvps-x automatically based on the frequency of the signal to display 4 periods of the signals on screen. Two things worth noting:
- If auto period is used with a very slow frequency signal, it will take a very long time to fill the buffer and refresh the graph. Trace mode is more useful for signals >1Hz.
- If the hvps-x is producing a DC voltage (e.g. output is HIGH), there is nonetheless a value in the frequency field, and this value is used to calculate the refresh rate.
2.2.3 Other Options section
- If turn off on quit is checked, the voltage set point of the hvps-x will be set to 0 and the optocouplers deactivated upon closing the interface. The default state of this check box can be changed in the config.ini file. If it is checked by default, the output will also be de-activated upon launching the interface.
- Current selection jumper allows the selection of the current configuration jumper on the PCB. It does not change the output current! It is used to inform the GUI of the hvps-x output current. This value is used for the custom waveform tab. The jumper position remains valid until the hvps-x is power-cycled. To make the selection permanent, you need to save the settings using the Save button (10). The current values displayed next to the jumper position will be 120uA and 240uA if you haven’t performed a current calibration. Otherwise, it will show your calibrated values.