Siemens SIMATIC ET 200S - Page 362

1PosUniversal/Digital
7.6 Functions of the 1PosU
ET 200S Positioning
362 Operating Instructions, 05/2007, A5E00124871-04
Wire Break/Short Circuit of the Encoder Signals Response of the 1PosU
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.
• 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
• Feedback bit SYNC = 0
•
Generate channel-specific diagnostics
• Waits for error acknowledgment EXTF_ACK
• Inching MODE is not affected by this error.
• The current JOB (reference signal evaluation) is canceled.