Function library
Function blocks
3.5.12 BCD decade switch (BCD)
3−121
l
EDSVS9332P−EXT DE 2.0
3.5.12.2 Signal processing
Reading the BCDs:
Output Signal Function
BCDx−EOT
LOW Beginning of the BCD reading.
HIGH If
· all 8 absolute value digits and the sign are transmitted or
· "CANCEL" has been identified.
BCDx−NEW−DATA
LOW After a LOW−HIGH edge at BCD−READ.
HIGH After the transmission of a BCD is completed.
BCDx−DATA−FLT HIGH If "BCD error" has been identified (see table in chapter 3.5.12.1).
BCDx−FAIL HIGH If
· the permissible value range for the target code is exceeded or
· BCDx−DATA−FLT = HIGH has occurred before.
BCD_A
BCD1x-LOAD
BCD1x-BUSY
BCD1x-FAIL
Correct transmission
Wrong transmission
Fig. 3−76 Signal shape for FB BCD1 for the transmission to the target code
Transmission sequence of data to the target code:
Output Signal Function
BCDx−LOAD LOW−HIGH edge Transmits the signal to the target code.
BCDx−BUSY HIGH For the time of transmission
BCDx−FAIL HIGH If a transmission error occurs.
Only another LOW−HIGH edge at BCDx−LOAD switches BCDx−FAIL = LOW.
Transmission error:
· No target code
· No target subcode.
· transmitted data are out of the target code limits.
· "BCD error" has been identified (BCDx−DATA−FLT = HIGH).
· The target code is inhibited. Code can only be written when the controller is inhibited.
For the data conditioning for the target code see FB FEVAN. ( 3−195)
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