Siemens Simatic S7-200 System Manual page 165

Example: PID Loop Instruction
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S7-200 Instruction Set
Network 1 //On the first scan,
//Call the initialization subroutine
LD SM0.1
CALL SBR_0
Network 1 //Load PID parameters and
//attach the PID interrupt routine:
//1. Load the loop setpoint = 75% full.
//2. Load the loop gain = 0.25.
//3. Load the loop sample time = 0.1 seconds.
//4. Load the integral time = 30 minutes.
//5. Set no derivative action.
//6. Set the timed interval (100ms)
// for timed interrupt INT_0.
//7. Set up a timed interrupt to invoke
// the PID execution.
//8. Enable interrupts
LD SM0.0
MOVR 0.75, VD104
MOVR 0.25, VD112
MOVR 0.1, VD116
MOVR 30.0, VD120
MOVR 0.0, VD124
MOVB 100, SMB34
ATCH INT_0, 10
ENI
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