Siemens SIMATIC S7-200 System Manual page 292

S7-200 Programmable Controller System Manual
POSx_RSEEK Instruction
The POSx_RSEEK instruction (Seek Reference Point
Position) initiates a reference point seek operation, using
the search method in the configuration/profile table. When
the Position module locates the reference point and motion
has stopped, the Position module loads the RP_OFFSET
parameter value into the current position and generates a
50-millisecond pulse on the CLR output.
The default value for RP_OFFSET is 0. You can use the
Position Control wizard, the EM253 Control Panel, or the
POSx_LDOFF (Load Offset) instruction to change the
RP_OFFSET value.
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 RSEEK
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 RSEEK 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 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.
Table 9-13 Parameters for the POSx_RSEEK Instruction
Inputs/Outputs
START
Done
Error
278
Data Type Operands
BOOL I, Q, V, M, SM, S, T, C, L, Power Flow
BOOL I, Q, V, M, SM, S, T, C, L
BYTE IB, QB, VB, MB, SMB, SB, LB, AC, *VD, *AC, *LD