Siemens simatic et 200s Operating Instructions Manual page 362

1PosUniversal/Digital
7.6 Functions of the 1PosU
Wire Break/Short Circuit of the Encoder Signals
If an SSI encoder is used:
Prerequisite:
To detect errors of the encoder signals, you must
•
enable the "Encoder signal diagnostics" parameter.
Causes:
Wire break or short circuit of the encoder signals at
•
terminals 9 and 13 or 12 and 16.
The parameters for the SSI encoder do not
•
correspond to the encoder connected.
What to Do:
Check the wiring and correct the short circuit.
•
Compare the parameter assignment with the
•
technical specifications of the encoder.
Acknowledge the error with the EXTF_ACK control
•
bit.
If an incremental encoder is used:
Prerequisite:
The encoder signal diagnostics parameter must be
•
enabled in order to allow error recognition for the
signals A, /A and B, /B at 5 V differential signals or
for the signals A and B at 24 V signals.
The zero marker diagnostics parameter must be
•
enabled in order to allow error recognition for the
signals N, /N at 5 V differential signals. If you use an
encoder without a zero mark, switch off error
detection. If dosing operation is activated, zero
marker signal diagnostics is not possible.
Causes:
For 5V differential signals only:
•
Wire break or short circuit of the encoder signals at
terminals 9 and 13 or 11 and 15 or 12 and 16.
Edge error of the encoder signals recognized so that
•
1PosU cannot carry out clear direction recognition.
What to Do:
Check the wiring and correct the short circuit.
•
Acknowledge the error with the EXTF_ACK control
•
bit.
362
Response of the 1PosU
The current MODEs relative positioning and absolute
•
positioning are stopped; it is not possible to start a new run
in these MODEs.
– All 3 digital outputs are set to 0.
– Feedback bit POS_ERR = 1
– Feedback bit POS_DONE = 0
Feedback bit ERR_ENCODER=1
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Feedback bit SYNC = 0
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Generate channel-specific diagnostics
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Waits for error acknowledgment EXTF_ACK
•
Inching MODE is not affected by this error.
•
The current JOB (reference signal evaluation) is canceled.
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Operating Instructions, 05/2007, A5E00124871-04
ET 200S Positioning