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Master/Slave Operation
© National Instruments Corporation
The DAQArb may be phase locked to other devices or other DAQArb
devices in either of two ways, as shown in Figure 4-21. You can use
master/slave phase locking to synchronize multiple devices in a test
system.
Master
NI Device
Slave
DAQArb
Slave
DAQArb
a. RTSI Bus Master/Slave
Configuration Device
Figure 4-21. Master/Slave Configurations for Phase Locking
Example 1, shown in Figure 4-21a, shows any National Instruments
device with RTSI bus capability as the master. To phase lock the
DAQArbs to this master, perform the following steps:
1. Set the National Instruments device (master) to send a 20 MHz
signal over the RTSI bus on the RTSI Osc line. If this device is a
DAQArb, set the source for the RTSI clock line to board clock for
NI-DAQ software and internal for LabVIEW.
2. Set up the slave devices so that the PLL reference source is set to
the RTSI clock line.
3. Set the PLL reference frequency parameter to 20 MHz.
4. The boards should now be frequency locked to the master.
5. To further phase lock the boards, set up the master to send the
trigger signal on one of the RTSI trigger lines.
6. Set up the slaves to receive their trigger signal on the RTSI bus.
7. Start the waveform generation on all the slaves
8. Start the waveform generation on the master.
9. All the slaves will be triggered by the master and will be phase and
frequency locked to each other and the master.
Slave
DAQArb
Slave
DAQArb
Slave
DAQArb
b. External
Master
4-23
Chapter 4
Arb Operation
Ref In
Ref In
Master
Ref In
DAQArb 5411 User Manual
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