Measurement Computing TempScan/1100 - Manual (Page 257)

TempScan / MultiScan User’s Manual 889897 API Command Reference A-61
Y
- Set Counts
TYPE Acquisition
EXECUTION Deferred
SYNTAX Ypre,
post,
stop
Set acquisition counts where pre is the Pre-Trigger count, post is the Post-
Trigger count and stop is the Post-Stop count.
Y? Query current acquisition count selections.
DESCRIPTION
For either the TempScan/1100 or MultiScan/1200 unit, the Set Counts (
Y ) command is used to set a Pre-Trigger,
Post-Trigger, and Post-Stop scan count to define the size of the acquisition. The optional Pre-Trigger count
cannot exceed the memory size, but the required Post-Trigger count can. If the Post-Trigger count exceeds the
memory size, it is the responsibility of the PC/IEEE 488 controller to deplete the FIFO Acquisition Buffer as the
data is being collected, or else a buffer overrun error will occur. The optional Post-Stop count can also be
associated with an acquisition to collect samples after the Stop (trigger stop event) occurs.
If a Trigger (trigger start event) 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 following User Status (
U ) command query –
Query the Buffer Status String ( U6 ) – can be used to check the Pre-Trigger count. Although normal Pre-Trigger
scans are acquired as soon as the acquisition is armed, they are not available or valid until the Trigger occurs.
For the MultiScan/1200 only, in single-channel high-speed burst mode, samples are internally collected for the
selected channel in 256-sample blocks. However, this externally appears the same as 256-channel scans in the
line-cycle integration / high-speed multi-channel mode. That is, when you program the number of 256-sample
blocks in the Post-Trigger count parameter
post of the Set Counts ( Y ) command, you will retrieve the data from
the MultiScan/1200 unit as "Post-Trigger count" scans of 256 samples.
The single-channel high-speed burst mode is a one-shot operation, since it collects the specified number of
samples and then stops. It is not continuous, and does not allow memory overflow and wrap-around. The
maximum amount of samples which can be taken is dictated by the amount of memory available, as follows:
Single-Channel High-Speed Burst Mode
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
Note: The TempScan/1100 or MultiScan/1200 unit can be configured to have different timebases for its Pre-
Trigger and Post-Trigger states. When the Trigger condition is satisfied, the unit goes from the Pre-
Trigger state to the Post-Trigger state, changing its timebase, if configured to do so. For more information,
see section Acquisition Configuration in the chapter System Configuration.
Note: For the MultiScan/1200 only, in single-channel high-speed burst mode, the Post-Trigger count parameter
post is used to select the number of 256-sample blocks to collect.
EXAMPLE
PRINT#1,"OUTPUT07;Y100,1000,50X" ‘ Configure acquisition counts for 100 Pre-Trigger scans,
1000 Post-Trigger scans, and 50 Post-Stop scans
PRINT#1,"OUTPUT07;N0 N2 X" ‘ Configure Event Status Register Bit ( ESB ) of the Status
Byte Register ( STB ) to be set when the Pre-Trigger
count is satisfied
PRINT#1,"OUTPUT07;T1,8,0,0X" ‘ Set Trigger as Trigger On ( @ ) command, and set Stop as
Counts