Compliance Limit - Keithley 6430 Instruction Manual

5-2 Source-Measure Concepts

Compliance limit

When sourcing voltage, the SourceMeter can be set to limit current (from 1fA to 105mA).
Conversely, when sourcing current, the SourceMeter can be set to limit voltage (from 200µV to
210V). The SourceMeter output will not exceed the compliance limit.
NOTE
Types of compliance
There are two types of compliance: "real" and "range." Depending upon which value is
lower, the output will clamp at either the displayed compliance setting (real compliance) or at
the maximum possible compliance value for the fixed measurement range (range compliance).
This clamping action effectively limits the power that can be delivered to the device. When the
SourceMeter is acting as a current source, the voltage is clamped at the compliance value; con-
versely, the current is clamped at the compliance value when the SourceMeter is acting as a
voltage source. Note that range compliance cannot occur if the AUTO measurement range is
selected. Thus, to avoid range compliance, use AUTO range.
When in real compliance, the source clamps at the displayed compliance value. For exam-
ple, if the compliance voltage is set to 1V and the measurement range is 2V, output voltage will
clamp at 1V. In this case, the "CMPL" annunciator will flash.
When in range compliance, the source output clamps at the maximum compliance value for
the fixed measurement range (not the compliance value). For example, if compliance is set to
1V and the measurement range is 200mV, output voltage will clamp at 210mV. In this situation,
the units in the compliance display field will flash. For example, with the following display:
Vcmpl: 10mA, the "mA" units indication will flash.
For the following discussion, "measurement range" refers to the measurement func-
tion that is the opposite of the source function. When sourcing voltage, the current
measurement range is the point of discussion. Conversely, when sourcing current,
the voltage measurement range is the point of discussion.