Siemens SIMATIC S7-200 System Manual page 294

S7-200 Programmable Controller System Manual
POSx_LDPOS Instruction
The POSx_LDPOS instruction (Load Position) changes the
current position value in the Position module to a new
value. You can also use this instruction to establish a new
zero position for any absolute move command.
Turning on the EN bit enables the instruction. Ensure that
the EN bit stays on until the Done bit signals that the
execution of the instruction has completed.
Turning on the START parameter sends a LDPOS
command to the Position module. For each scan when the
START parameter is on and the Position module is not
currently busy, the instruction sends a LDPOS command to
the Position module. 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 Position module reports
and uses for absolute moves. Based of 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 module completes
this instruction.
The Error parameter contains the result of this instruction. See Table 9-20 for definitions of the
error codes.
The C_Pos parameter contains the current position of the module. Based of the units of
measurement, the value is either a number of pulses (DINT) or the number of engineering units
(REAL).
Table 9-15 Parameters for the POSx_LDPOS Instruction
Inputs/Outputs
START
New_Pos, C_Pos
Done
Error
280
Data Type Operands
BOOL I, Q, V, M, SM, S, T, C, L, Power Flow
DINT, REAL ID, QD, VD, MD, SMD, SD, LD, AC, *VD, *AC, *LD
BOOL I, Q, V, M, SM, S, T, C, L
BYTE IB, QB, VB, MB, SMB, SB, LB, AC, *VD, *AC, *LD