Keithley 6487 Reference Manual

Model 6487 Reference Manual Triggering 7-7
Measure action
The measure action block of the trigger model is where a measurement is performed.
However, if the repeating filter is enabled (Figure 7-3), the instrument samples the speci-
fied number of reading conversions to yield single filtered reading. Only one reading con-
version is performed if the digital filter is disabled or after the specified number of reading
conversions for a moving average filter is reached.
If a voltage sweep is active, one measure action per voltage step is performed.
Figure 7-3
Measure action block of trigger model
Output triggers
The Model 6487 can send out an output trigger (via the rear panel TRIGGER LINK
connector) right after the measure action and/or when operation leaves the trigger layer.
An output trigger can be used to trigger another instrument to perform an operation
(e.g., select the next output step for a source).
Counters
Programmable counters are used to repeat operations within the trigger model layers. For
example, if the trigger count is set for 10, operation will keep looping around in the trigger
layer until 10 measurements are performed. If the arm count is set to 2, operation will then
loop back through the arm layer and go back into the trigger layer to perform 10 more
measurements.
Filter Process (Repeat)
CONV CONV CONV
CONV = Reading Conversion
Measure Action

Keithley 6487 Specifications

General

Type	Picoammeter/Voltage Source
Current Measurement Range	20 fA to 20 mA
Interfaces	GPIB, RS-232
Voltage Burden	< 200 µV
Input Impedance	>10^14 Ω
Power	100 V / 120 V / 220 V / 240 V
Basic Current Measurement Accuracy	0.4%