Siemens SIMATIC S7-200 System Manual page 519

S7-200 Quick Reference Information
To help you find information more easily, this section summarizes the following information:
Special Memory Bits
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Descriptions of Interrupt Events
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Summary of S7-200 CPU Memory Ranges and Features
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High-Speed Counters HSC0, HSC1, HSC2, HSC3, HSC4, HSC5
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S7-200 Instructions
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Table G-1 Special Memory Bits
Special Memory Bits
SM0.0 Always On
SM0.1 First Scan
SM0.2 Retentive data lost
SM0.3 Power up
SM0.4 30 s off / 30 s on
SM0.5 0.5 s off / 0.5 s on
SM0.6 Off 1 scan / on 1 scan
SM0.7 Switch in RUN position
SM1.0 Result of operation = 0
SM1.1 Overflow or illegal value
SM1.2 Negative result
SM1.3 Division by 0
SM1.4 Table full
SM1.5 Table empty
SM1.6 BCD to binary conversion error
SM1.7 ASCII to hex conversion error
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