BECKHOFF FC5101 - Manual (Page 23)

Eiserstraße 5 / D-33415 Verl / Telefon 05246/963-0 / Telefax 05246/963-149
23
Slave
In slave synchronization mode the card receives its time basis from a sync master. The sync master is selected
at the corresponding field.
· Sync Master: PC-Task. This is the default setting. The PC provides the time basis using the TwinCAT
Real Time. Depending on the settings the Task start (Default with TwinCAT NC) or the Task end (De-
fault at TwinCAT PLC) triggers the SYNC telegram.
· Sync Master: Balanced PC Task. This operating mode as well generated the CANopen Sync cycle
with the long term accuracy of the PC time basis. However, the short term accuracy (interval between
two SYNC telegrams) is better that with Sync Master "PC-Task":
- Run time differences (e.g. caused by case dependent program calls) are leveled out,
- the FC510x delays pending transmit telegrams until the SYNC telegram was sent,
- the SYNC intervals are determined by the quartz timer of the FC510x card.
The card timer is adjusted in small steps to the PC-timer if the difference is larger that the value of the
"PLL Sync Time".
In this mode the SYNC telegram is delayed for the Shift Time after the end of the TwinCAT task cycle.
Here the shift time should be set to a value as small as possible - but large enough to allow the proc-
ess data access by the TwinCAT task. The function "Calculate Equi-Times" helps to configure the op-
timal shift time. It is started by selecting the corresponding button.