Siemens SIMATIC S5 Manual page 294

STEP 5 Programming
Indicator elements/outputs
Output
Q 2.0 No external start enable signal (IP pin 7)
Q 2.1 IP not initialized/synchronized
Q 2.2 No reference point
Q 2.3 IP in follow-up mode
Q 2.4 Axis not in position
Q 2.6 "Lower drill"
Q 2.7 "Raise drill"
QB 5 Error code, hexadecimal (KH)
9-6
Lights when/is on when
IP 266
Call in
FB 26
OB 1
FB 26
FB 26
FB 26
FB 20
FB 20
FB 20
EWA 4NEB 812 6057-02