Fault Messages - Siemens SIMATIC S5 Equipment Manual

Matching Module 4 for Absolute Encoders

7.3.6 Fault Messages

By evaluation in the programmable controller, states deviating from normal operation can
be recognized.
Normal operation can always be recognized by a synchronization bit set to"1" ("synchronization"
LED is not lit up) and a sign bit VZ set to "O".
bit VZ is set with "O", then an encoder error has occurred or the control bit polarity has been set
wrong! This error can only occur in "operation mode with control bit evaluation" (switch S4 is
closed).
If the synchronization bit of the IP241 is set with "O" ("synchronization" LED lights up) andthesign
bit VZ is set with"1", an overflow has occurred!
Encoder resolution > 20 bits (overflow)
Encoder resolution 17 to 20 bits with binary or gray code encoders and BCD
conversion setting (see section 7.3.1 .1).
Software synchronization is illegal for this encoder matching module!
After the initial turning on, the number of TBs is missing (the module firmware sets TB = 35)
Loss of parameterization (e.g., the firmware sets TB = 35 in case of power off) until the time of
parameter transfer from the programmable controller.
Software reset of the 1P 241 (firmware sets TB = 35) until the time the parameter TB is trans-
ferred.
A control bit is set on the matching module (S4 closed), but no control bit is output by the
connected encoder. (The error message is output independent of a possible overflow.)
The set polarity of the control bit (switch S1 ) does not match the polarity of the encoder. (The
error message is output independent of a possible overflow.)
The control bit is set, but the number of TBs specified is too small.
An overflow occurs (i.e., the sign bit is set with"1 ").
An encoder with more than 20 bits is connected, causing an overflow when the 20 bits are
exceeded.
The encoder requires a higher number of clock pulse groups (for TB > 20) than the specified
resolution (i.e., internal zeroes are inserted and a wrong direction of rotation is specified
(switch S3).
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Possible error sources:
R 02/92