Actual Position Value Preparation - Siemens SINAMICS S150 Operating Instructions Manual

Functions, monitoring, and protective functions
9.4 Extended functions
9.4.5.1

Actual position value preparation

Description
Actual position value preparation prepares the actual position value in a neutral length unit
LU. 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 9-15
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
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).
354
Actual position value preparation with rotary encoders
Drive converter cabinet units
Operating Instructions, 07/07, A5E00288214A