Keithley 2002 User Manual page 272

Query
Description
Program fragment
Parameters
Query
Description
Program fragment
Parameters
:FEED? Query buffer feed
This command is used to select the source of readings to be placed in the buffer. With SENSe[1]
selected, raw readings are placed in the buffer when storage is performed. With CALCulate[1]
selected, calculated math readings (POLYnomial or PERCent or NONE) are placed in the
buffer.
With NONE selected, no readings are placed in the buffer when storage is performed over the
bus.
PRINT #1, "output 16; :trac:feed calc; feed?"
PRINT #1, "enter 16"
:[PERCent] <n>
:TRACe:FEED:PRETrigger:AMOunt:[PERCent] <n>
<n> = 0 to 100 % of buffer for pre-trigger readings
DEFault 50% of buffer for pre-trigger readings
MINimum 0% of buffer for pre-trigger readings
MAXimum 100% of buffer for pre-trigger readings
:[PERCent]?
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 are
continuously 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 continuously fill the buffer. When the pre-trigger event
occurs, subsequent readings will then be stored starting at buffer location 26 and continue 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. See paragraph 2.8.2 for more information about
pre-trigger.
PRINT #1, "output 16; :trac:feed:pret:amo 25; amo?"
PRINT #1, "enter 16"
:READings <n>
:TRACe:FEED:PRETrigger:AMOunt:READings <n>
No memory
option
<n> = 0 to 404
0 to 2027
MAXimum Present buffer size (which is set by TRACe:POINts)
DEFault Half present buffer size (which is set by TRACe:POINts)
MINimum 0 (all cases)
' CALC1 buffer readings
' Get response from 2002
Specify percentof pre-trigger readings
' 25%
rdgs
' Get response from 2002
Specify number of pre-trigger readings
MEM 1 MEM 2
0 to 1381 0 to 5980
0 to 6909 0 to 29908
IEEE-488 Reference
for pre-trigger
(Full)
(Compact)
3-149