Agilent Technologies 6812B, 6813B, 6811B manual Using Transient Voltage Modes

4 - Front Panel Operation

Condition

OV Condition

OCP Condition

SOA Condition

OT Condition

RI Condition

Rail Condition

Action

Usually overvoltage conditions are caused by an external source forcing voltage into the output of the ac source. Remove this external source to eliminate the overvoltage. You can also program the overvoltage level to a higher value, or turn the overvoltage protection off.

In other cases the output voltage may have exceeded the user-programmed overvoltage level. In this case the unit may have inadvertently been programmed to a voltage that exceeded the programmed overvoltage level. The VOLTage:PROTection command sets the overvoltage protection level.

Note: The overvoltage protection level is programmed in peak, not rms volts.

If the CURRent:PROTection:STATe command has been programmed to to disable the output when rms current limit is activated, the unit will shut down. The rms current limit threshold is set by the CURRent command. In this case you must check to see why the load is drawing more current than the limit that has been programmed by the CURRent command.

Protection circuits in the ac source let the load draw peak currents for short periods of time that exceed the continuous capability of the unit. This allows loads that require large inrush currents to turn on. The ac source will shut down if a combination of peak current duration and internal component temperature exceeds a predetermined limit.

When this occurs, it means that the load has been drawing peak output currents that are beyond the capability of the ac source to supply for extended periods. Slower output slew rates and reduced peak current limit settings can be used to control the conditions that cause SOA shutdowns.

When the internal operating temperatures of the ac source exceed predetermined thresholds, the output turns off. If this happens, you must let the unit cool down before continuing operation.

If the Remote Inhibit input has been programmed to to disable the output when it receives an external signal, the unit will shut down. The Remote Inhibit input is set by the OUTPut:RI:MODE command. In this case you must check to what external event produced a signal on the RI input.

The internal high voltage rail that provides power for the ac source’s output is continuously monitored for proper voltage level. If this voltage is not maintained within predetermined levels, the output will shut down. This can happen if an extenal source forces too much power into the ac source or if too much power is drawn from the ac source.

Remove the external source to eliminate the rail condition. Slower output slew rates and reduced peak current limit settings can also be used to control the conditions that cause rail shutdowns.

6 - Using Transient Voltage Modes

The ac source voltage can be programmed in the following transient operating modes:

STEP	causes the output to permanently change to its triggered value.
PULSE	causes the output to change to its triggered value for a specific time, as determined by the
	Pulse menu parameters.
LIST	causes the output to sequence through a number of values, as determined by points entered
	in the List menu.
FIXED	disables transient operation for the selected function.

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