HBM PX401, Руководство по эксплуатации

Страница: 120 / 552

Synchronization and Time recording
120
A4354-2.2 HBM: public
PMX
9 Synchronization and Time recording
If measurement signals need to be referenced over time
with each other for processing and analysis, for measure­
ment data acquisition tasks (DAQ), for example, they
must be synchronously recorded. That is why all PMX
modules can be synchronized with one another. This en­
sures simultaneous measurement on all channels. An
internal counter is used for this, and every PMX has one.
Counter format used: 48­bit integer
Counter frequency: 153.6 kHz
At a sampling rate of 19.2 kHz (factory setting) the
counter is therefore incremented by 8 from one measured
value to the next.
At a sampling rate of 38.4 kHz the counter is incremented
by 4 from one measured value to the next.
These counters are included in the transfer of every
measured value. The absolute measurement time must
come from a different source. This can be the internal
time from the PMX, or another external clock. The meas­
urement data acquisition system then synchronously
combines the measured values with the counter and time
stamp.
To achieve a precise reference over time, the applicable
channels must be parameterized with the same filter set­
tings. No automatic runtime correction is carried out. The
filter runtimes are shown in the data sheet.
When PMX devices are connected, the carrier frequency
and the time stamp can be synchronized via the SYNC
socket. The status can be read from the LED.
The master/slave allocation is automatic.