User's Manual

HARSFEN0602
PT motion must start with initial programming of the PT arrays.
First set
MP[1] = First valid line in the PT table
MP[2] = Last valid array in the PT table
MP[3] = 1 for cyclical mode.
MP[4] = the ration between the length of the PT time interval and the sampling time of the position
controller
MP[5] = Number of yet unused QP[N] elements when a “PT queue low” emergency object is sent. Set to
zero if no “PT queue low” warning is desired.
MP[6]=the write pointer. This is the next position in the QP[N] vector to be written by the CANopen object
0x2002.
Set the QP[N] for at least the first two points in the PT motion. This is since the PT algorithm requires at
least two time points to interpolate a motion trajectory. Set at least 3 points if the speed at the second point is
to be continuous.
Set (if not already set) UM=4 or UM=5, and MO=1
Set PT=N, where QP[N] and QP[N+1] and preferably QP[N+2] are all programmed to valid values.
Then use the CAN PT/Auto increment command for the rest of the PT motion.
Keep informed how the PT motion advances, either by receiving the read and the write PT table pointers
continuously, mapped to a synchronous PDO, or by using the queue low emergency signal to signal the need
for more data. The queue low emergency message includes the present location of the read pointer and the
write pointer. It is safe to send more PT data PDOs until the write pointer is one location before the read-
pointer specified by the queue low emergency message.
The host is well aware to the location of the write pointer, since it can count its own messages. A data
message may be, however, rejected since the queue is full, or since a message is lost. In that case, the
Amplifier will issue an emergency object to the host. After receiving the emergency object the true location
of the write pointer may be unclear. The host may then set MP[6] to the possibly rejected table row and
continue the writing from there.
12.1.7.9 The Parameters of The PT Motion Mode
The following parameters apply to PT motion
What How Comment
Unit Mode (UM) Unit modes 3,4 or 5 select a
position mode.
Stop Deceleration (SD) The rate of deceleration in
the case where motion is
killed by queue underflow or
by an exception.
SD is also the acceleration to
catch up with a PT motion
started with bad initial
conditions.
Position/ Time (PT) Set a PT motion command Special features are available for
PT using CAN communication
PT table entries: QP[N] Set values to the PT table
MP[1] = First valid row in
PVT table
MP[2] = Last valid row in
PVT table
Motion Parameters (MP)
MP[3] = Cyclical motion (0
non-cyclical, 1 cyclical)
Configure a PT or PVT motion.
MP[6] and MP[5] are for the CAN
auto increment mode only.