Danaher Motion
06/2005
Single-Axis Motion
This program works by starting a slow move with low torque. The move
continues until position error is greater than 0.25 units. When the axis runs
into a stop, position error accumulates because the profile continues. You
must be careful to set the threshold of the event greater than the position
error of normal operation. The threshold of the event must also be smaller
than the drive's maximum following error to avoid drive error before the event
is triggered. Disable
OnEvent
during the acceleration of the move to avoid
nuisance PartFound events.
4.2.6. PIPEMODE
The MC controller can be used as a pure SERCOS interface card between
your application and SERCOS drives (PIPEMODE feature). The host
computer controlls all of what normally occurs in the motion module of the
MC. It must send a realtime stream of data through the MC to the drives. In
this case, the MC functions as a data pipe. The feature is enhanced by the
option of flexibly switching between pipe mode and regular mode. In typical
applications, the MC starts in regular mode where homing, jogging and initial
position adjustments are made. After that, the MC can be switched to pipe
mode and the host computer takes control. There can be both MC-controlled
and pipe-controlled axes at same time in the system. Following error and
velocity over-speed errors are not checked with piped axes, but by the host.
An external profiler path can be designed and fed to the MC point-by-point.
The controller functions only as a pipe and is not responsible for the
correctness of the applied profiler. No system limits are checked except for
position error and feedback velocity limitation. While running under this
mode, no other movements are allowed.
Command points are written through the standard Fast-Data DPRAM
interface and transmitted into the controller. The DPRAM is scanned every
SERCOS cycle and the command is executed.
There can be up to eight (8) axes in the system operating in pipe-mode. The
Fast-Data interface can be configured in one of two communication protocols
using
SYS.PIPEMODE
: 1 – sending position command only, 2 – sending
both position and velocity commands. When the system's pipe mode uses
only position commands, the controller computes the current velocity.
Depending on the pipe mode configuration, the controller limits the number
of axes that can be operated in this mode. When system uses only position
command, eight (8) axes can operate. When using both position and velocity
values, only four (4) axes can operate.
4.2.6.1. D
ATA
S
TRUCTURE
The host CPU passes position and velocity commands via a data structure
through the Fast-Data DPRAM. The API maps the data to
SYS.HOSTDOUBLE
. The SERCOS operation mode of every drive
connected to an axis working in Pipe Mode must be configured
(Position/Velocity/Torque). The drive operation mode is selected through a
status word written in
SYS.VIN
.
NOTE
Only drive modes previously configured in the SERCOS setup
can be selected.
M-SS-005-03 Rev
E
103
