Siemens SIMATIC S5-100U, Системное руководство, Страница: 117 / 552

S5-100U Addressing
Time-Controlled Program Processing
Access to the interrupt PII is expressed by the “PB” or “PW” operand identifiers in a statement in
the time-controlled program.
The letter “L” represents the “Load” operation (see chapter 8).
Figure 6-10. Accesses to the Interrupt PII
L PW 76
• Byte-by-byte reading “PB <byte address>”
Example: Reading in the signal states of all
channels of an 8-channel digital input module
in slot 21
• Word-by-word reading “PW <word address>”
Example: Reading in the analog value of
channel 2 of a 4-channel analog input module
in slot 1
Interrupt PII
Byte 21
Byte 76
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High byte
0 15
L PY 21
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ACCU 1
Low byte
0 15
ACCU 1
High byte Low byte
Interrupt-Driven Program Processing
• When a process interrupt occurs, only the data of the interrupt inputs, slots 0 and 1, is read into
the interrupt PII.
• Only this data of the interrupt PII is available to the interrrupt-driven program for evaluation.
• In a statement in the interrrupt-driven program, access to the interrupt PII is possible only with
the following operands: PB0, PB1, and PW0.
• If other parameters are specified, the CPU goes into the STOP mode and the “NNN” error
message is specified in the ISTACK. See section 5.2.
EWA 4NEB 812 6120-02b
6-13