Vishay 7000 - Page 29

Vishay Micro-Measurements System 7000 Programmer’s Reference Manual
Page 29 of 142
Upper Limit
The upper limit value is used in checking the test condition. The upper limit is used by the
Greater Than, Equal, Between, Outside, and Range conditions. This value is entered in
analog-to-digital converter counts.
Strain Gage 1 count = 0.5µε, or 0.25µV/V
High-Level 1 count = 100µV
Thermocouple 1 count = 1µV
LVDT 1 count = 50 µV
rms
Table 6
Number of “Pre-Limit” Scans
The System 7000 buffers a defined number of scans. You may specify that when a limit is
tripped you would also like to record some number of scans that occurred just previously.
You must specify the number of “pre-limit” scans that you would like to have recorded. If
you'd like to think of acquiring N number of seconds of "pre-limit" data, use the following
formula to convert time into scans.
NumScans = ScanRate * Time
Number of “Post-Limit” Scans
You may also specify some number of scans that should be recorded after the limit goes
inactive. If you'd like to think of acquiring N number of seconds of "post-limit" data, use the
following formula to convert time into scans.
NumScans = ScanRate * Time
Table 7 shows that
three limits are
defined.
This table should be
passed to each card
in the scanner. Note:
the indexes must be
assigned sequentially
(i.e. do not skip an index).
LabVIEW Configure Limit Condition VI
Active X ConfigureLimitCondition method
Low-level Set Limit Event Condition command
Set Lower Limit Value command
Set Upper Limit Value command
Set Pre-trigger Buffer Size command
Set Post-trigger Buffer Size command
Index Condition Lower
Limit
Upper
Limit
Pre-Limit
Scans
Post-Limit
Scans
0 Greater Than not used 1000 100 0
1 Less Than 50 not used 0 0
2 Outside 700 800 0 0
:
None not used not used 0 0
:
None not used not used 0 0
49 None not used not used 0 0
Table 7