Siemens SIMATIC S5 Manual page 47

IP 266
Error recovery
Rectify the error by interchanging the signal lines.
Symmetrical encoders (5 V)
To change the counting direction, reverse
A/A\ and B/B\.
Proceed as follows:
Switch off the 24 V power supply for the IP 266.
Remove the encoder cable from the module.
Reverse the signal lines as shown in the table above.
Reconnect the encoder and switch on the 24 V supply.
The module once again checks the position control direction, switching off its
position control monitor when the check produces a correct result.
When the "Follow-up" mode is exited, the position control monitor is re-
enabled and is not disabled again until the new check produces a correct
result.
C A U T I O N :
Whenever you replace an encoder, always remember to switch off the module's
24 V power supply. Only then can the module's position control monitor detect
an incorrect position control direction.
EWA 4NEB 812 6057-02
Technical Description of the IP 266
Asymmetrical encoders (24 V)
To change the counting direction, reverse A*
and B*.
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