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Discharge on Unpowered Keysight 3070 Systems

Discharge on Unpowered Keysight 3070 Systems

(Rev 13 Oct 98) The article entitled "The Mysterious Workings of Analog/.Discharge" (see link below) is applicable to both powered and unpowered Keysight 3070 systems, but does not explain how a discharge routine is created on an Unpowered system. In some cases customers may put a board onto the Keysight 3070 system where the board already has a charge on it from some external functional tester. In order to avoid the potential of welding relays, a discharge routine is needed for these instances.

In fact, IPG still uses the equation E = 1/2 C*V*V when deciding which caps need to go in the .discharge file, putting in capacitors whose potential power (E) is greater that 200 u joules. The part that needs explaining is what value is used for the voltage (V). In powered systems, the voltage used is the sum of the DUT supplies as defined in the board file, as long as power supplies are specified.

On a powered system where no supplies are specified in board, and on unpowered systems (since there are no DUT supplies), a different method is used.

If there is no operator intervention, IPG will assume a five volt supply. This means that any capacitor who's value is over 16uFd will be placed into a discharge file created by the system.

In some cases the five volt assumption is insufficient to create an adequate discharge routine. In fact, the voltage used in the calculation is selectable anywhere between 1 and 100 volts. This should allow for almost all situations.

In order to change the default voltage used, first verify that discharge is NOT marked permanent in the testorder file (it never should be, but it doesn't hurt to check). Next go into a Unix shell and enter the desired voltage. For example if 50 volts is desired, enter;

$ export APG_DEFAULT_VOLTAGE = 50

Once that is done, convert to a basic window by typing "basic" in the same Unix shell window, and run Test Consultant. Finally you should verify the new entries in the analog/.discharge routine are correct. It may also be worth making a backup of your new discharge file to avoid potentially losing the information in case Test Consultant is ever re-run without remembering to export the desired default voltage.

Documents & Downloads

EPT HP3070 Analog Discharge 

Application Note 1998-01-01

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