6
6.2
Positioning mode (P0700 = 3, from SW 2.1)
6-393
Siemens AG 2005 All Rights Reserved
SIMODRIVE 611 universal Description of Functions (FBU) – 04.05 Edition
The reference cam must be long enough, so that when the cam is
approached with the reference point approach velocity, the braking
travel ends right at the cam (the axis comes to a standstill at the cam),
and the cam is exited with the reference point shutdown velocity.
The minimum length of the reference cam is calculated as follows:
Min. length =
(reference point approach velocity)
2
2
deceleration
=
P0163
2
2
P0104
Note:
This only applies if the jerk limiting is not active (P0107 = 0), otherwise longer.
Table 6-32
Reference cam up to the end of the traversing range?
If...,
Then ...
the cam ex-
tends up to the
end of the tra-
versing range,
Recommenda-
tion
the reference point approach can be started from every
point of the axis.
Reason:
There are 2 conditions in this case (in front of and actually
at the cam).
The axis behaves appropriately at the start of the reference
point approach, and traverses correctly for the reference
point approach.
the reference
cam does not
extend up to the
end of the tra-
versing range,
The axis must be traversed into the range, determined at
start–up, before the reference point approach is started.
Reason:
In this case, there are 3 initial conditions (in front of, at or
behind the cam). The drive cannot differentiate between in
front of and behind the cam, and for the reference point
approach, for a specific initial condition it does not reach
the reference cam.
Axes, which only have one zero mark over their complete traversing
range (e.g. rotary axes), do not require any reference cams when refe-
rencing.
A reference point approach for these axes is executed as follows:
1. Synchronization with the zero pulse (phase 2,
refer to ”axis with reference cams” (P0173 = 0)”
2. Travel to the reference point (phase 3,
refer to ”axis with reference cam (P0173 = 0)”
What is the
minimum length of a
reference cam?
Axis without
reference cams
(P0173 = 1)
6 Description of the Functions
01.99
! not 611ue !
06.04