Omega Engineering OMB-CHARTSCAN 1400, User Manual

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Appendix A API Commands
ChartScan User’s Manual A-63
Y
- Set Counts, or Select Blocks
TYPE Acquisition
EXECUTION
Deferred
SYNTAX
Ypre,post,
stop
When in Normal mode of data acquisition, set acquisition counts where
pre
is the pre-trigger count,
post
is the post-trigger count and
stop
is the
post-stop count.
Y0,count,0
When in High-speed, single-channel mode (burst mode) , set
count
; where
count
is the number of 256 sample blocks to be collected
Y?
Query current acquisition count selections.
DESCRIPTION
Normal Mode
When in Normal mode for data acquisition, the Set Counts (
Y
) command can be used to select a pre-trigger,
post-trigger, and post-stop count to define the size of the acquisition. The pre-trigger count cannot exceed the
memory size, but the post-trigger count can. If the post-trigger count exceeds the memory size, it is the
responsibility of the IEEE 488 controller to deplete the FIFO buffer as the data is being collected, or a buffer
overrun error will occur. A Post Stop Event Count can also be associated with an acquisition to collect a counted
amount of samples after the Stop Event occurs.
If a trigger is encountered before the pre-trigger count is satisfied, the unit will trigger but have fewer than the
specified pre-trigger count in its buffer. The Buffer Status String (
U6
) command can be used to query the box for
the size of the pre-trigger. Although normal pre-trigger scans are acquired as soon as the acquisition is armed,
they are not available or valid until the start trigger event occurs.
Note: The unit can be configured to have different timebases for its pre-and post-trigger states. When the user-
specified trigger condition is satisfied, the unit goes from the pre-trigger to the post-trigger state, changing
its timebase, if configured to do so. Refer to the
Continuous, Gap-Free Acquisition with Two Timebases
in Appendix B for more information.
High-Speed, Single-Channel Mode
When in High-speed, single-channel mode (burst mode) ;
count
(see syntax) is used to select the number of 256
sample blocks to collect. Valid values for
count
are as follows:
System Memory Post-Trigger Count*
256 Kbytes
2
to
512
1 Megabytes
2
to
2048
4 Megabytes
2
to
8192
8 Megabytes
2
to
16384
*In each case, the number assigned for block count must be a power of 2.
EXAMPLE for Normal Mode
PRINT#1, “OUTPUT07;Q1,0,1,1,1X”
‘ Set the reading separator flag ON
PRINT#1, “OUTPUT07;F0,0X”
‘ Data format is engineering units, degrees C
PRINT#1,"OUTPUT07;C1-4,1X"
‘ Configure channels 1 - 4 as T/C type J
PRINT#1,"OUTPUT07;I00:00:01.0,
00:00:00.1”
‘ Configure scan interval
PRINT#1,"OUTPUT07;Y100,1000,50X"
‘ Configure acquisition counts
PRINT#1,"OUTPUT07;N0 N2 X"
‘ Configure Event Status Register Bit (ESB) to be set when
pre-trigger count is satisfied
PRINT#1,"OUTPUT07;T1,8,0,0X"
‘ Configure acquisition, start trigger is Trigger On (
@
)
command, stop trigger is Counts
S% = 0
‘ Wait for the pre-trigger count to become satisfied
WHILE (S% AND 32) = 0
PRINT#1,"SPOLL07"
INPUT#2,S%
WEND
PRINT#1,"OUTPUT07;N0 N1 X"
‘ Configure ESB to be set when acquisition is complete
S% = 0
‘ Wait for the acquisition to become complete
WHILE (S% AND 32) = 0
PRINT#1,"SPOLL07"
INPUT#2,S%
WEND
PRINT#1,"OUTPUT07;U6X"
‘ Get Buffer Status String
PRINT#1,"ENTER07"
‘ Retrieve the response
INPUT A$
‘ Screen shows
0000001,0001151,-0000100,
10:02:02.0,04/24/93,00001000,
10:23:30.0,04/24/93,00001050,01
‘ Indicates that 100 pre-trigger scans were acquired 1000
post-trigger scans were acquired and 50 post-stop
scans were acquired