Measurement Computing Data Translation DT9857, User Manual

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Chapter 5
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When synchronizing multiple DT9857E modules, start the slave modules before starting the
master module. When the master DT9857E module is triggered, both the master and the slave
modules start acquiring or outputting data at the same time (within one A/D or D/A
conversion of the clock). If you specified a reference trigger (external digital trigger or
threshold trigger for the master, and the Sync Bus for the slaves), the master and the slaves
will start acquiring the specified number of post-trigger scans when the reference trigger is
detected on the master (you must specify the number of post-trigger scan count for the master
and the slaves). Note that you can set the clock rate to be the same or different on each module
but correlation of the data will be difficult if the clock rates are not the same or are not
multiples of each other.
Note: It is important that you start the slave modules first, followed by the master module
so that the slave receives the appropriate clock and trigger signals from the master.
If you start the master module before the slaves, the slaves never start; you will see a delay of
approximately 20 seconds if you try to stop or abort the analog input operation on a slave
module that is waiting for a trigger.
If you are not using a reference trigger and you stop the master module, the slaves continue
to run and return data until you stop the analog input subsystem on the slave modules. Be
sure to stop the analog input subsystems on all slave modules before disconnecting the cable
from the Sync Bus connectors.