Siemens Simatic S7-200 System Manual page 276

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 9-13 on page 276 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).
9
Table 9-8
Inputs/Outputs
START
New_Pos, C_Pos
Done
Error
264
Parameters for the POSx_LDPOS Instruction
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