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IP 240
13
Encoder Signals
This section discusses the requirements for the forms and timing of the signals for the IP 240. The
following encoder signals are discussed in this section:
•
Incremental encoder signals for position decoding, IP 252 expansion and positioning mode
( Section 13.1).
•
The signal at binary input IN for reference point approach and for synchronization with an
external control signal for position decoding and positioning mode ( Section 13.2).
•
The signals at counting input CLK and at binary input GT for counting mode ( Section 13.3).
13.1
Signal Forms and Timing Requirements for Incremental Encoders
13.1.1 Signal Forms
In position decoding, IP 252 expansion and positioning mode, the incremental encoders used for
producing position-dependent signals must generate two square-wave pulse trains in quadrature.
If you want to execute a reference point approach in position decoding and positioning mode, at
least one high-active zero mark signal (reference signal) per encoder revolution is also required.
You can connect incremental encoders to the IP 240 which generate
•
symmetrical signals A/A, B/B and Z/Z; the IP interface for these encoders conforms as regards
the level to the RS 422A standard.
•
asymmetrical signals A*, B* and Z* with a rated encoder voltage of 5 V or 24 V.
To match the IP 240 to the type of encoder and the signal level, you must set coding switches S4,
S5 and S6 ( Section 5.3).
A/A*
A
B/B*
B
Z/Z*
Z
Fig. 13-1. Signal Forms: Symmetrical Encoder Signals A/A, B/B, Z/Z
Note
To change the counting direction, you must interchange the connections as
follows:
•
for symmetrical encoders, interchange A/A with B/B
•
for asymmetrical encoders, interchange A* with B*
EWA 4NEB 811 6120-02a
90°
Asymmetrical Encoder Signals A*, B*, Z*
Encoder Signals
t
13-1
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