Agilent Technologies n3304a manual Input Control, Protection Features, Short On/Off, Input On/Off

2 - General Information

Input Control

Short On/Off

A module can simulate a short circuit at its input by turning the load on with full-scale current. The short circuit can be toggled on/off at the front panel using the SHORT command in the Func menu, or via the GPIB (INPUT:SHORT ONOFF command). The short on/off change uses the slew rate setting of the active mode and range.

The actual value of the electronic short is dependent on the mode and range that are active when the short is turned on. In CV mode it is equivalent to programming zero volts. In CC mode it is equivalent to programming full-scale current for the present current range. In CR mode it is equivalent to programming the minimum resistance for the present resistance range.

Note that turning the short on in CV mode may cause the load to draw so much current that the software current limit operates, which may turn the input off.

Turning the short circuit on does not affect the programmed settings, and the load input will return to the previously programmed values when the short is turned off.

Input On/Off

A module's input can be toggled on/off at the front panel, or via the GPIB (INPUT ONOFF command). The input on/off change does not use the slew rate setting so the input will change at the maximum slew rate.

Turning the input off (zero current) does not affect the programmed settings. The input will return to the previously programmed values when the input is turned on again. Note that the Input On/Off command supersedes the mode commands and Short On/Off command.

Protection Features

Each load module includes the following protection features:

•Overvoltage.

•Overcurrent (hardware and software).

•Overpower.

•Overtemperature.

•Reverse Voltage.

The appropriate bit(s) in the mainframe's status registers are set when any of the above protection features are active. Also, the Prot annunciator comes on and the front-panel alphanumeric display indicates which condition(s) have been detected. For example, if an overtemperature (OT) condition has been detected causing a module's input to be turned off (protection shutdown, PS), the display will indicate "PS OT".

Resetting Latched Protection

All of the protection features latch (remain set) when they are tripped, except for the hardware overcurrent and reverse voltage. The latched protection features can be reset via the GPIB (*RST or INP:PROT:CLE commands) or at the front panel. Of course, the condition that caused the protection feature to trip must be removed or it will trip again as soon as it is reset.

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