Siemens simatic et 200s Operating Instructions Manual page 151

Relative Positioning: Causes of Errors for POS_ERR
You must find out the causes of errors with JOB 15 (displays current values).
Error Number Cause
3 ERR_ENCODER is displayed
5 The limit switch that lies in the direction in
which the drive is moved is active
7 Relative positioning:
Start with DIR_P and DIR_M = 0 or DIR_P and
DIR_M = 1
13 Direction of rotation of the drive and the
encoder varies
ET 200S Positioning
Operating Instructions, 05/2007, A5E00124871-04
4.6 Functions of the 1PosInc/Analog
What to Do
Check the encoder wiring
Check your switches and the wiring as well as the DI0
limit switch minus and DI1 limit switch plus
parameters
Check the wiring of the drive and the encoder as well
as the reversal of the direction of rotation parameter
1PosInc/Analog
151