Siemens Simatic S7 Series

Open loop motion control
12.6 Subroutines created by the Motion wizard for the Axis of Motion
S7-200 SMART
System Manual, 09/2015, A5E03822230-AC
515
12.6.8
AXISx_LDPOS subroutine
Table 12- 18 AXISx_LDPOS
LAD / FBD
STL
Description
CALL AXISx_LDPOS,
START, New_Pos,
Done, Error, C_Pos
The AXISx_LDPOS subroutine (Load Position) changes the current
position value in the Axis of Motion to a new value. You can also use
this subroutine to establish a new zero position for any absolute move
command.
Table 12- 19 Parameters for the AXISx_LDPOS subroutine
Inputs/Outputs
Data type
Operands
START
BOOL
I, Q, V, M, SM, S, T, C, L, Power Flow
New_Pos, C_Pos
DINT, REAL
ID, QD, VD, MD, SMD, SD, LD, AC, *VD, *AC, *LD
Done BOOL I, Q, V, M, SM, S, T, C, L
Error
BYTE
IB, QB, VB, MB, SMB, SB, LB, AC, *VD, *AC, *LD
Turn on the EN bit to enable the subroutine. Ensure that the EN bit stays on until the Done
bit signals that the execution of the subroutine has completed.
Turn on the START parameter to send a LDPOS command to the Axis of Motion. For each
scan when the START parameter is on and the Axis of Motion is not currently busy, the
subroutine sends a LDPOS command to the Axis of Motion. To ensure that only one
command is sent, use an edge detection element to pulse the START parameter on.
The New_Pos parameter provides the new value to replace the current position value that
the Axis of Motion reports and uses for absolute moves. Based upon the units of
measurement, the value is either a number of pulses (DINT) or the engineering units
(REAL).
The Done parameter turns on when the Axis of Motion completes this subroutine.
The Error parameter (Page 545) contains the result of this subroutine.
The C_Pos parameter contains the current position of the Axis of Motion. Based upon the
units of measurement, the value is either a number of pulses (DINT) or the number of
engineering units (REAL).