Keithley 2001 User Manual

IEEE-488 Reference
4-216
Description This command is used to specify how much of the defined buffer (:POINts) will be used to store
pre-triggered readings. When a pre-trigger store is started (see :FEED:CONTrol), readings will
continuously be stored in the buffer. When the pre-trigger event occurs (see :PRETrig-
ger:SOURce), post-trigger readings will then fill the part of the buffer that is not reserved for
pre-trigger readings.
For example, assume 25% of a 100 point buffer is reserved for pre-trigger readings. When the
pre-trigger store is started, readings will continuously fill the buffer. When the pre-trigger event
occurs, subsequent readings will then be stored starting at buffer location 26 and continuing until
buffer location 100 is filled. Storage stops after buffer location 100 is filled. The result is 25
pre-trigger readings and 75 post-trigger readings.
Programming example 10 OUTPUT 716; “:trac:feed:pret:amo 25; amo?”
20 ENTER 716; A$
30 PRINT A$
40 END
Line 10 Two commands in this program message; the first specifies that 25% of the buffer
will be used for pre-trigger readings, and the second queries the percentage.
Line 20 Addresses the Model 2001 to talk.
Line 30 Displays the percentage of the buffer to used for pre-trigger readings (25).
:READings [BUFFER,] <n>
:TRACe:FEED:PRETrigger:AMOunt:READings [BUFFER,] <n> Specify number of pre-trigger
readings
Parameters No memory
Option MEM 1 MEM 2
<n> = 0 to 250 0 to 1400 0 to 6000 (Full)
= 0 to 850 0 to 7000 0 to 30000 (Compact)
= MAXimum Present buffer size (TRACe:POINts)
= DEFault Half present buffer size (TRACe:POINts)
= MINimum 0
Format :trac:feed:pret:amo:read <n>
Defaults Power-up 5
*RST No effect
:SYSTem:PRESet No effect
Query :READ? [BUFFER,]
Short-form formats: :trac:feed:pret:amo:read?
Response message: 0 to 30000
Description This command is used to specify how much of the defined buffer (:POINts) will be used to store
pre-triggered readings. This command is essentially the same as the :PERCent command except
the amount is expressed as an exact value instead of a percent.

Keithley 2001 Specifications

General

Model	2001
Category	Multimeter
Manufacturer	Keithley
Type	Digital Multimeter
Digits of Resolution	7.5
DC Voltage Range	100 mV to 1000 V
AC Voltage Range	100 mV to 750 V
Frequency Range	3 Hz to 500 kHz
Connectivity	GPIB, RS-232
Display	VFD
Resistance Accuracy	0.008% + 2.0 mΩ
Frequency Accuracy	±0.01%
DC Current Range	10 μA to 3 A
AC Current Range	10 μA to 3 A
Power Supply	100 V to 240 V AC, 45 Hz to 66 Hz