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Distributed Clocks

Slave Controller – Technology I-67

The second option uses a SyncSignal output of ESC 1 to trigger Latch0 at ESC 2 and an interrupt at

the µController. Upon receiving an interrupt, the µController writes the time of the SyncSignal pulse to

the System Time register of ESC 2. The µController has to calculate the time of the SyncSignal based

upon Start Time Cyclic Operation and SYNC Cycle Time configuration of ESC 1 from interrupt to

interrupt. The advantage of the second solution is less communication, the disadvantages are more

calculation overhead and error detection/troubleshooting.

ESC 1

DC source

Sync0

IRQ

ESC 1 generates SyncPulse

for ESC 2 and IRQ for µC

µC writes Sync time of ESC 1

(calculated by µC) to System

Time register of ESC 2

µController

ESC 2

destination

Latch0

Figure 33: System Time PDI Controlled with two steps

1 2 ... 82 83 84 85 86 87 88 89 90 91 92 ... 115 116

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Beckhoff EtherCAT Technology Section I Manual do Utilizador Página 87