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General Information 17
Front panel operation:
You can use the front panel when the unit is operating in Simulator mode. To do this, press the Local key whenever the
front panel RMT annunciator is on. Be aware however, that any voltage and current values that you enter from the front
panel will have no effect on the unit while it is in Simulator mode. These front panel values will take effect as soon as the
unit is placed in Fixed mode. Likewise, the OCP function only takes effect in Fixed mode. All other functions such as Local,
Error, Output On/Off, Protect are active while the unit is operating in Simulator mode.
Table Mode
In Table mode, the output characteristic is determined by a user-defined table of voltage/current points (see Figure 1-3).
Table mode operation is achieved by sampling the output voltage, applying a low-pass filter, and continually adjusting the
constant current loop by using the filtered voltage as an index into the stored table of points. Linear interpolation is used to
set the current when the filtered voltage does not have an exactly matching table entry. What this means is that the I-V curve
is generated by connecting the points in the table by straight lines. The more points that you provide, the more accurate the
curve will be when the points are connected.
I
V
sc
oc
I
V
0
E4351B = 4A
480W MAX
= 1
Ω
min (E4351B)
.25
Ω
min
(
E4350B
)
V
I
MAXIMUM
VOLTAGE
TYPICAL CURVE
MAXIMUM CURRENT
E4350B = 8A
120V 130V = E4351B
60V 65V = E4350B
POINTS UNDER
DASHED LINE
ARE INVALID
Figure 1-3. Table Mode Characteristic
Each table can have a maximum of 4,000 output points (3,500 points if it will be stored in non-volatile memory). Each
output point is defined by a voltage/current coordinate pair of values that define the location of the point on the curve. The
first value is the voltage, the second value is the current. If no point is supplied for V=0, the current associated with the
lowest voltage entry point is defined as Isc and the curve will be extended horizontally to the current axis. If no point is
supplied for I=0, the slope that was determined by the last two current entry points will be extended to the voltage axis.
Multiple tables can be defined and saved in non-volatile memory (which is limited to 3500 points), or volatile memory
(which is limited to 30,000 points). Up to 30 tables can be saved in each memory.
Restrictions
■ The number of points in a table can vary from 3 to 4000, but an equal number of voltage and current values must be
sent. Otherwise an error will occur when the table is selected with CURRent:TABLe:NAME. Use
MEMory:TABLe:CURRent:POINts? and MEMory:TABLe:VOLTage:POINts? to find the length of an existing table.
■ Points must be above dashed line shown in Figure 1-3.