Siemens CPU 313C Hardware And Installation Manual page 221

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When the operating system detects a specific error (e.g. access error with
67(3 ), it calls a dedicated organization block (Error OB) that determines
subsequent CPU response.
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Response to a Æ runtime error. The operating system can respond in the following
ways: transition of the PLC to STOP mode, call of an organization block in which
the user can program an error response or display.
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Power supply for the signal and function modules and the I/O connected to them.
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Æ Function Block
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Æ Function
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FEPROMs are the same as electrically erasable EEPROMS in that they can retain
data in the event of a power failure, but they can be erased much more quickly
(FEPROM = Flash Erasable Programmable Read Only Memory). They are used on
Æ Memory Cards.
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No galvanic connection to ground.
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The Force function is used to assign fixed values to certain variables from a user
program or CPU (including I/Os).
In this context, please note the limitations listed in the 2YHUYLHZ RI WKH WHVW
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According to IEC 1131-3 a function is a Æ code block that contains no Æ statical
data. A function allows parameters to be passed in the user program. Functions
are therefore suitable for programming frequently occurring complex functions,
e.g. calculations.
S7-300 Automation Systems, Hardware and Installation: CPU 31xC and CPU 31x
A5E00105492-03
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13-5