Kollmorgen AKD

AKD CANopen | 7 CANopen Drive Profile
7.2.2.15 Object 3496h: Fieldbus synchronization parameters
This set of objects is used to set or read parameters for the fieldbus synchronization used in the interpolated posi-
tion mode (7) and the cyclic-modes 8 etc. The synchronization between a fieldbus master and the AKD is similar
in all the supported fieldbus systems.
The AKD internal 16[kHz] interrupt function is responsible for calling the PLL function. This PLL function is called
once per fieldbus cycle (set by object 60C2 sub 1 and 2).If the fieldbus sample period is for example 1[ms], the
PLL code is called every 16th time of the 16[kHz] IRQ of the AKD.
Once in a fieldbus sample the SYNC-telegram must arrive, which resets a PLL counter in the Drive. After some
time the already mentioned PLL function is called and reads back the time from that PLL counter.
Depending on the measured time the PLL function extends (in case that the measured time is too low) or lowers
(in case that the measured time is too high) the sample time of the upcoming 16[kHz] tasks for one fieldbus sam-
ple by a selectable value (object 3496 sub 4) in order to move the PLL function closer to the expected distance
(object 3496 sub 1).
Beside the objects mentioned here the parameter FBUS.SAMPLEPERIOD is important, which is set by object
60C2 sub 1 and 2.This setting is required in order to share the fieldbus sample time with the slave. This infor-
mation is e.g. needed for being able to call the AKD internal PLL function once per fieldbus sample.
Index 3496h
Name FBUS synchronization parameters
Object code Array
Data type UNSIGNED32
Category optional
Subindex 0
Description number of entries
Category mandatory
Access R/O
PDO mapping not possible
Value range 0x4
Default value 0x4
Subindex 1
Description FBUS.SYNCDIST
Category optional
Access R/W
PDO mapping not possible
Value range UNSIGNED32
Default value 320000 [ns]
Sub 1 is the expected time distance in nano seconds between clearing the PLL counter and calling the PLL func-
tion.
Subindex 2
Description FBUS.SYNCACT
Category optional
Access R/W
PDO mapping not possible
Value range UNSIGNED32
Default value 320000 [ns]
Sub 2 is the actual time distance in nano seconds between clearing the PLL counter and calling the PLL function.
70 Kollmorgen™ | November 2012