Positioning functionality

• Setup:
  Move the rapid-traverse or creep-speed axis into position at the touch of a button (jog mode).
• Absolute incremental feed:
  The axis is moved to an absolute target position. The numerical values are stored in a table on the FM 451.
• Relative incremental feed:
  The axis is moved through a set route.
• Reference point motion:
  For synchronization after the PLC has been turned in when using incremental position encoders.

Special functions

• Set actual value
• Set reference point
• Delete distance to go

Mode of operation

Preparatory steps for a positioning task:

• Coordination of mechanical system and electronics:
  Easily achieved by entering machine data.
• Specify target position(s) via the S7 CPU or configuration software
• Transfer the interface signals from the CPU to the FM 451 (start, stop)

The FM 451 handles the actual positioning:

• 4 digital outputs controlling the rapid-traverse, creep-speed, counterclockwise and clockwise functions are assigned to each channel.
• Creep speed or rapid-traverse/creep speed is specified depending on the distance to the target.
• After the cutoff point is reached, the module monitors the target approach. After the target area is reached, a signal is sent to the CPU.