Siemens SIMATIC S5 Manual page 270

Start-Up
8.1.4 The Incremental Position Encoder
Control precision depends on the location of the encoder in the drive system. A
sequence of movements can be easily verified when the encoder is mounted
directly on the motor axis.
Check to make sure that the encoder is correctly installed.
You must use an encoder which supplies two pulse trains displaced by 90 deg.
with respect to each other and a zero mark signal.
You may use a 5 V or a 24 V encoder.
In addition to all required signals, the 5 V version must also supply the
inverted signal for each signal.
.
Which encoder version are you using?
If you are using a 5 V encoder, check the following:
Does the encoder supply the inverted signals?
You must select an encoder resolution that enables evaluation of a sufficient
number of pulses per interval even at low speeds. The minimum resolution
should be greater than the positioning accuracy.
The maximum operating frequency of encoder and module must not be
exceeded at V . The maximum operating frequencies for 5 V and 24 V
max
encoders are as follows:
• For symmetrical
• For asymmetrical 24 V encoders: 100 kHz (for a max. cable length of 25 m)
8-4
5 V encoders: 500 kHz
24 V encoders: 25 kHz (for a max. cable length of 100 m)
IP 266
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EWA 4NEB 812 6057-02