25
If you do not want to keep the new configuration, press the RECALL key to return to
the Recall menu, then press the CLR
→
key to restore the P400 to its previous state.
5.10
Power-Up States
Press the POWER button to turn the P400 on or off. The P400 starts in the last
configuration used before power down. On power-up, all programmable settings are
restored to their previous state except RUN state, which is set to STOP. The display
shows the Trigger menu.
The P400 can be set to a demonstration mode by pressing and holding the “0” key
while powering up. See Section 4, “Quickstart,” for details.
5.11
High Voltage Option
P400 DDGs may be furnished with the P450 high-voltage option. This adds five
rear-panel BNC connectors which produce transformer-isolated high-voltage
pulses corresponding to the T0, A, B, C, and D pulses.
If the high-voltage option is installed, the AUX menu will include five user-
programmable variables which set the voltage levels of each of the five HV
outputs. The levels may be set from 0 to 50 volts (measured into an external 50
ohm load) in 0.1 volt steps. Output is inherently low impedance so should be
terminated in 50 ohms to maintain proper pulse shapes.
CAUTION: do not connect easily-damaged loads to the high-voltage outputs
without suitable protection, shunt zener diodes or equivalent.
An equivalent circuit of the HV output is shown in Figure 13.