Figure 2-1. Constant Current Mode
Immediate Current Level
The current level can be set at the front panel (
and ENTRY keys) or via the GPIB (CURR command). If the CC mode is the active mode, the new setting immediately changes the input at a rate determined by the slew setting (described below). If the load is not in the CC mode, the new setting is saved for use when the mode is changed to CC.
Triggered Current Level
The current level can be preset (stored in the Electronic Load) allowing the input to be updated when a trigger is received instead of immediately as previously described. The current level can only be preset via the GPIB (CURR:TRIG command). The preset capability is not available at the front panel.
If the CC mode is the active mode, the preset current level will become the actual value and the input will be updated when a trigger occurs. If the CC mode is not the active mode, the preset current level will become the actual value when a trigger occurs but there will be no effect on the input until the CC mode becomes active. Once a level is triggered, subsequent triggers will have no effect on the input unless another CURR:TRIG command is sent. The trigger sources available to the Electronic Load are described later in this chapter. The Electronic Load has a status reporting capability to keep track of pending triggers and other operating conditions. The status reporting capability is described in detail in the Programming Reference Guide.
Transient Current Level
The transient current level can be set at the front panel ( 
, 
and ENTRY keys) or via the GPIB
(CURR:TLEV command). The transient current level determines the higher current level when transient operation (described later in this chapter) is turned on. The load will switch between the main level and the transient level when transient operation is turned on.
Software Current Limit
The Electronic Load allows the user to set a current limit from 0 to 102% of full scale via the GPIB (CURR:PROT command), which will shut down the input if the current limit is exceeded beyond a programmable time delay. Note that the software current limit is in effect for any mode of operation (not just the CC mode). The software current limit feature is described later in this chapter under Protection Features.