Explanation Of The Mnemonics Used In "Istack - Siemens S5-100U User Manual

Simatic s5 programmable controller

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Explanation of the Mnemonics Used in "ISTACK"

Table 5-5. Meaning of the Remaining ISTACK Bits

relevant for CPU 103 only

for CPU 102: 0 = normal mode

1 = test mode

EWA 4NEB 812 6120-02

Shift block.

Execute shift operation.

Structure address list.

Internal control bit for STOP/RUN change

Battery backup available

PLC not yet in cycle after Power ON

- See bytes 9 and 10 for cause.

Interrupt enable/enabling of time-controlled OB13 and interrupt-

Program contains errors.

Block header cannot be interpreted.

Not enough S5 statement memory available

Overall reset, program defective

Program contains errors.

Condition code bits for arithmetic, logic, and shift operations.

Arithmetic overflow

ID bit of OR memory

Status ID of operand of last binary statement executed

Result of logic operation (RLO)

ID bit of first scan

OR parenthesis open

AND parenthesis open

Diagnostics and Troubleshooting

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