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9.4.6.1
Actual position value preparation
Description
The position actual value conditioning converts the actual position values into a neutral
distance unit LU (Length Unit). For this purpose, the function block uses the Gn_XIST1,
Gn_XIST2, Gn_STW and Gn_ZSW encoder interfaces available in the encoder evaluation/
motor controller. These simply provide the position data in encoder bars and fine resolution
(increments).
The position actual value is conditioned, regardless of whether the position controller is
enabled immediately after the system has booted, as soon as valid values are received via
the encoder interface.
Parameter p2502 (encoder assignment) defines the encoder (1, 2 or 3) used to record the
actual position value.
The following connection is run automatically after assignment:
● p0480[0] (G1_STW) = encoder control word r2520[0]
● p0480[1] (G2_STW) = encoder control word r2520[1]
● p0480[2] (G3_STW) = encoder control word r2520[2]
Figure 9-33
The link between the physical variables and the neutral length unit LU is established via
parameter p2506 (LU per load revolution) for rotary encoders. Parameter p2506 along with
p2504, p2505 reflect the link between encoder increments and the neutral length unit LU.
Example:
Rotary encoder, ball screw with a pitch of 10 mm/revolution. 10 mm should have a resolution
of 1 µm (i.e. 1 LU = 1 µm)
-> One load revolution corresponds to 10000 LU
-> p2506 = 10000
Note
Effective actual-value resolution
The effective actual value resolution is obtained from the product of the encoder pulses
(p0408) and the fine resolution (p0418) and a measuring gear that is possibly being used
(p0402, p0432, p0433).
Enclosed Drives
Operating Instructions, 12/2018, A5E36652151A
Position actual value conditioning with rotary encoders
Functions, monitoring and protective functions
9.4 Extended functions
635
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