Pressure Systems 9046 - Manual (Page 51)

Pressure Systems, Inc. Model 9046 User’s Manual
Page 45 www.PressureSystems.com
When the hardware trigger is used to synchronize stream scans (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 averaged scans of 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 any configured streams. 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 to
update internal Thermal Scan data and check UTR Thermal Alarms.
When all hardware triggered streams are complete or terminated, an individual module will
return to the default mode of continuous scanning and EU conversion. When the internal
software clock
is used to control host stream output rates (sync=1), note that 1000 Hz 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, a common hardware trigger wired to all modules should be used.
The period ‘ per’ parameter is a positive decimal integer count (from 0 to 2147483647 (largest
32-bit positive number), specified with 1 to 10 numeric digits as needed), and its meaning
depends on the sync type ‘
sync’ parameter described above.
’syn
c meaning of ’per’
0 number of hardware trigger periods to wait before sending
each scan
1 delay period (in milliseconds) to wait before sending each
scan NOTE: Values 0 to 9 will select a minimum 10
millisecond period.