maxon motor control
EPOS Positioning Controller
EPOS Application Note: Interpolation Position Mode
6
maxon motor control
Edition December 2008 / Subject to change
2.4
SYNC-Time stamp mechanism
The SYNC-Time stamp mechanism can be used to synchronize the motion clock of the drive with a master clock in
the network.
Device
Master
Device
Time (TimeOfD
ay)
SYNC
HR_TimeStam
p(Tm1)
SYNC
HR_TimeStam
p(Tm2)
Tm = 0
Td1
Tm1
Tm2
Td2
Td = 0
Td = Td + Tm1 – Td1
Td = Td + Tm2 – Td2
Figure 2:
Clock synchronization
The synchronization method is similar to IEEE 1588 and uses the CANopen DSP301 SYNC Service (COB-Id 0x80)
and the
High Resolution Time Stamp Object (0x1013).
The SYNC Frame will be transmitted periodically by the SYNC master and the exact transmitting time (Tm1) should
be stored in the master by latching an internal 1us timer. The reception time (Td1) of the SYNC message will be
stored by latching the device internal motion clock timer. As following up the measured transmitting time (Tm1) will
be send to the drive with the High Resolution Time Stamp. The device adjusts then its internal motion clock time in
relation to the time latched in the last SYNC.
By sending a CANopen DSP301 TIME Service (default COB-Id 0x100 or defined by Object 0x1012) the device
internal motion clock timer can be reset to zero.
