IOtech DaqBook/2000 Series, Руководство пользователя

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8-4 Taking Measurements
898695
DaqBook/2000 and DaqOEM/2000 Series
Synchronization Model for DaqBook/2000 and DaqOEM/2000 Series Devices,
DaqBook/2020 uses BNC
connectors for EXTCLK
and TRIGGER inputs.
The other devices use
pins as indicated in notes
1 and 2.
Note 1 : For DaqBook/2001 and DaqBook/2005, the clock signal is from P1, pin 20.
For DaqOEM/2000 Series devices, the clock signal is from JP1, pin 2.
Note 2 : For DaqBook/2001 and DaqBook/2005 the trigger signal is from P1, pin 25.
For DaqOEM/2000 Series devices, the trigger signal is from JP1, pin 12.
In regard to synchronization, the following applies:
•
One of three signals can be used to drive the DaqBook’s acquisition scan rate. These are:
−
the internal acquisition pacer clock
−
an external acquisition pacer clock.
−
the global sync (G-SYNC) input from the SYNC ports
•
Both the SYNC connector input and the external clock input can be divided down.
•
When a DaqBook is in the Master Mode, both the trigger condition and the scan timing are output
on the SYNC port. The global trigger (G-TRIG) is selected instead of the TTL Trigger Input.
Whether the DaqBook is using its internal scan clock , or external clock input , it can be programmed to
output the clock on the SYNC connector. In either case, the unit is behaving like a synchronization
master . Other DaqBook units [that are connected to the master , via a SYNC port] should be programmed
as synchronization slaves .
When a DaqBook is programmed as a synchronization slave , it will derive its scan period from the SYNC
port. If the slave unit must be triggered at the same time as the master unit , then the slave unit should use
TTL Trigger as its trigger source .
Multi-unit synchronization via the SYNC ports does not support pre-trigger data.
Only post-trigger data can be collected and time correlated between the units.