F Execution Times For Stl Instructions - Siemens Simatic S7-200 System Manual

Execution Times for STL Instructions
Effect of Power Flow on Execution Times
The calculation of the basic execution time for an STL instruction (Table F-4) shows the time
required for executing the logic, or function, of the instruction when power flow is present
(where the top-of-stack value is ON or 1). For some instructions, the execution of that
function is conditional upon the presence of power flow: the CPU performs the function only
when power flow is present to the instruction (when the top-of-stack value is ON or 1). If
power flow is not present to the instruction (the top-of-stack value is OFF or 0), use a "no
power-flow" execution time to calculate the execution time of your program. Table F-1
provides the execution time of an STL instruction with no power flow (when the top-of-stack
value is OFF or 0) for each S7-200 CPU module.
Table F-1 Execution Time for Instructions with No Power Flow
Instruction with No Power Flow
All STL instructions
Effect of Indirect Addressing on Execution Times
The calculation of the basic execution time for an STL instruction (Table F-4) shows the time
required for executing the instruction, using direct addressing of the operands or constants. If
your program uses indirect addressing, increase the execution time for each indirectly
addressed operand by the figure shown in Table F-2.
Table F-2 Additional Time to Add for Indirect Addressing
Instruction for Indirect Addressing
All instructions except R, RI, S, and SI
R, RI, S, and SI
Effect of Analog I/O on Execution Times
Accessing the analog inputs and outputs affects the execution time of an instruction.
Table F-3 provides a factor to be added to the basic execution time for each instruction that
accesses an analog value.
Table F-3 Impact of Analog Inputs and Analog Outputs on Execution Times
Analog Inputs
Analog Outputs
S7-200 Programmable Controller System Manual
C79000-G7076-C230-02
10 µs
76 µs
185.3 µs
Model
171 µs
EM231, EM235
99 µs
EM232, EM235
F
CPU 212 CPU 214/215/216
6 µs
CPU 212 CPU 214/215/216
47 µs
120.2 µs
CPU 212 CPU 214/215/216
139 µs
66 µs
F-1