Siemens SIMATIC S5 Manual page 284

Start-Up
Possible errors:
1. The drive does not move although "Reference point set" is displayed.
You have accidentally executed a "Set reference point".
2. The drive traverses, but does not reduce its speed at the reference point
switch and does not find the reference point.
The reference point switch is either defective or is an "NC" contact.
3. The drive reduces its speed at the reference point switch, but continues
traversing until it reaches the limit switch. "Reference point deleted" is
displayed on the monitor.
The zero mark of the encoder is not used in the IP 266. You must test the
reference point switch signal and the zero mark signal.
If the reference point exists, the software limit switches are also effective.
Traverse in both directions in mode 1 or 2 and check to see whether the
software limit switches are tripped before the hardware limit switches are
reached.
If necessary, you must shift the coordinates of the software limit switches so
that the drive comes to a standstill before reaching the hardware limit
switches.
Increment mode
Once the coordinate system has been established, you can approach absolute
target positions.
Enter various different target positions in modes 6 and 7 and check to see if
the axis reaches these positions.
Executing automatic programs
Write a short traversing program and transfer it to the module.
Test this program in modes 8 and 9.
8-18
IP 266
EWA 4NEB 812 6057-02