Pressure Systems 9022 - Manual (Page 64)

Pressure Systems, Inc. NetScanner™ System (9016, 9021, & 9022) User’s Manual
www.PressureSystems.com 3 - 34
When the hardware trigger is used to synchronize data output ( sync = 0), it is
assumed that the user would prefer to also synchronize internal data acquisition
cycle. For this reason, when a stream utilizing hardware trigger is started, the
module firmware switches out of the free-running continuous data acquisition mode
described earlier. Instead, the module waits in an idle mode until a hardware trigger
is received to initiate a host stream output. Only on the receipt of that hardware
trigger will the module scan and EU convert all attached channels. Following
completion of the acquisition and EU conversion cycle, the module will also deliver
the requested data channels to the host. In this manner, users are provided with
highly synchronized data acquisition and delivery from one or more modules. If a
module waits in the idle mode for an extended period of time without receiving a
data request, it will periodically initiate its own internal data acquisition cycles so
as to update internal thermal coefficients.
When all hardware triggered streams are complete or aborted, an individual module
will return to the default mode of continuous scanning and EU conversion.
When the internal software timer is used to control host stream output rates
(sync=1), note that internal clock frequency variances will result in slightly different
timing between modules. Although these differences in timing are slight, they may
result in noticeable differences in output timing between modules over a long period
of time. If highly synchronized data output is required from multiple modules, the
hardware trigger mode should be used.
The period ‘per’ parameter is a positive decimal integer count (from 0 to
2147483647, specified with 1 to 10 numeric digits as needed), and its meaning
depends on the sync type ‘sync’ parameter described above.
‘sync’ meaning of ‘per’
0 number of hardware trigger periods to wait before sending each packet
1 delay period (in milliseconds) to wait before sending each packet NOTE:
minimum is 10 milliseconds