ElmoMC Multi-Axis Motion Controller-Maestro - Manual (Page 164)

Maestro Software Manual DS402 Command Reference
MAN-MASSW (Ver. Q)
10-19
As shown in section A of the diagram above, all synch periods have two stages- CAN
node operation time and synchronous command time.
Section B shows that the Maestro can send asynchronous commands without
synchronization.
Section C shows how the Maestro sends synchronous commands.
Section D shows the time sequence of group commands for profile position mode.
Command PA is asynchronous and the Maestro immediately starts sending these
commands. The command BG enables Maestro to send control words to the nodes
synchronously on SYNC. The node operation begins on the next SYNC. The motion starts
after a maximum of three synchronous times.
The performance time of asynchronous motion command is the sum of PDO message
sending time (sT≈0.5 msec for baud rate 500 kBt) to each member of the Vector (Group)
plus the operating time of the program (pT ≈0.5-1.0 msec). All motion commands for the
DS402 Group or Vector, except for bg, st, pcwd (or cwd).
nMembers sT pT me AsyncCmdTi
× + =
Asynchronous commands do not return control to the program before performance
completion by all members of the Group.
Synchronous commands do not wait for performance completion and return control
immediately. In the following sync message, another command is sent to each member.
The sync period depends on the number of synchronously working axes and one CAN
PDO message sending time (or from CAN bus baud rate).
nSyncAxes sT dT SyncTime
× + =
,
when:
dT=1 msec – DS402 device timeout
sT≈0.4 msec for baud rate 500 kBt
nSyncAxes – amount of synchronously working axes.
The maximum time of when movement begins after sending synchronous command
(e.g.-g1.bg) takes two sync periods.