Danfoss VLT Series Programming Manual page 47

Servo Drive Operation
Slave relative Blending
Cyclic
0 1
InSync
End of
pro le
Illustration 2.46 CAM 2: Partial CAM - Cyclic, Slave relative:
Blending Segment is an Automatically Calculated P5.
The CAM is adjusted in a way that the 1
matches the rotor angle of the last node.
A special case in Illustration 2.46 is when the velocity of the
last point and the velocity of the 1
the P5 is actually a P0.
For smooth movements with cyclic use of fully defined
st
CAM profiles, the 1 and the last data point of the profiles
must match each other. "Matching" means having the
same velocity value and, depending on the configuration,
also the slave position value (see Illustration 2.47 and
Illustration 2.48).
Slave relative
Cyclic
0 1
InSync
End of
pro le
Illustration 2.47 Cyclic, Full CAM Profile Defined Over the
Whole Guide Value Cycle.
The velocity of the 1 st and the last node are not equal. During
execution, a jump may occur.
MG36D102
Programming Guide
2
Guide value
cycle
st
rotor angle value
st
point are both 0. Then
Jump in velocity!
2
Guide value
cycle
Danfoss A/S © 01/2017 All rights reserved.
Slave absolute
Cyclic
Jump in position
and velocity!
0 1
InSync
End of
Illustration 2.48 Cyclic, Full CAM Profile.
The velocity and the position of 1
match.
Switching between CAM profiles
Depending on the CAM configuration options Master
absolute/relative and Slave absolute/relative, there are
several methods to transition from 1 running CAM profile
to the next. All the possibilities are described in the
illustrations in this section. The examples all show the
starting point based on the time of the CAM activation
request, or when CAM ack (bit 12) is set by the axis (see
chapter 2.4.5.1 Activating a CAM profile).
All illustrations in the following sub-chapters show the
transition from currently running CAM 2 (see
Illustration 2.41) to a newly activated CAM 1 (see
Illustration 2.40) or CAM 3 (see Illustration 2.42). The CAM
itself is always the same, but the illustrations show the
behavior with different configurations and settings.
The following conventions are used for transitions between
profiles:
•
The blending distance has no influence on the
position of the CAM (for example, regarding the
automatically calculated relative offset).
•
If a CAM profile is aborted (Change CAM
imm = 1), the current slave position is considered
as end slave position.
•
When activating a non-cyclic CAM profile with
Use blend distance = 0, the processing takes place
in the same master cycle (as the CAM activation
request) or in the next one (depending on the
end point of the currently running CAM profile
and the start point of the new CAM profile). In
both cases, the profile is processed as 1 complete
cycle (starting with the next upcoming start
node).
•
When activating a non-cyclic CAM profile with
Use blend distance = 1, the processing of it (at
least the start point) takes place in the same
master cycle (as the CAM activation request),
otherwise a CAM error is issued.
2
Guide value
cycle
st
and last nodes do not
45
2 2