Siemens SIMATIC S7-200

Quick review
1.6 The PLC scan cycle: Writing the outputs
Getting Started - Advanced
12 Training Documents, 09/2007, A5E01469795B
1.6 The PLC scan cycle: Writing the outputs
The outputs in the process-image output table (PIQ) are overwritten by the control logic in
the program. The bit states in the PIQ are transferred to the physical outputs in the final step.
The PLC scan cycle continuously repeats this process.
$W\SLFDOVFDQF\FOHWDNHVEHWZHHQDQGPV7KH
GXUDWLRQGHSHQGVRQWKHQXPEHUDQGW\SHRIQHWZRUN
ORJLFLQVWUXFWLRQV
7KHF\FOHFRQVLVWVRIWZRPDLQFRPSRQHQWV
 2SHUDWLQJV\VWHPWLPHW\SPVFRUUHVSRQGLQJ
WRSKDVH཰DQGིRQWKHSUHYLRXVSDJH
 7LPHIRUSURFHVVLQJWKHFRPPDQGVFRUUHVSRQGLQJ
WRSKDVHVཱಭRQWKHSUHYLRXVSDJH
,QDGGLWLRQWKHSURJUDPORJLFLVRQO\SURFHVVHGZKHQ
WKH3/&LVRSHUDWLQJLQRWKHUZRUGVZKHQLWLVLQ
581PRGH
