Siemens SIMATIC S5-100U, System Manual

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Function Modules S5-100U
Connect the sub-D interface female connector to an incremental position encoder that has to deliver
the following signals:
• Two counting pulses offset by 90 degrees
• A reference pulse
The pulses can be supplied as 5-V differential signals according to RS 422 (up to 500 kHz) or as
24-V DC signals.
Connect a switch to the enable input. This switch must deliver a 24-V signal. In the same way, the
reference pulse has to deliver a 24-V signal to the reference input.
Position Resolution
•
Counter capacity
The 16-bit up/down-counter permits a resolution of 65,536 units between -32,768 and +32,767.
The traversing range depends on the resolution of the position encoders.
• Pulse evaluation
The counting pulses, which are offset by 90 degrees, can be subjected to single, double, or
quadruple evaluation. The necessary setting is made on the operating mode switch (see
section 15.6).
The accuracy of the traversing path increases accordingly if double or quadruple pulse evaluation is
used. However, the traversing range then available is reduced by the factor 2 or 4.
Table 15-3. Pulse Evaluation
Counting pulse A
Counting pulse B
Count
Single
Evaluation
0 1 0 1 2 3 4
Quadruple
Evaluation
0 1 2
Double
Evaluation
15-30
EWA 4NEB 812 6120-02b