Siemens SIMATIC S7-200 - Page 391

IEC 1131-3 Instructions
10-3
S7-200 Programmable Controller System Manual
A5E00066097-02
Positive, Negative Transition
The Positive Transition contact allows power to flow for
one scan for each off-to-on transition.
The Negative Transition contact allows power to flow
for one scan, for each on-to-off transition.
In LAD, the Positive and Negative Transition instructions
are represented by contacts.
In FBD, the instructions are represented by the P and N
boxes.
Inputs/Outputs Operands Data Types
IN (LAD) Power Flow BOOL
IN (FBD) I, Q, M, SM, T, C, V, S, L, Power Flow BOOL
OUT (LAD) Power Flow BOOL
OUT (FBD) I, Q, M, SM, T, C, V, S, L, Power Flow BOOL
P
N
P
N
IN OUT
IN OUT
222 224
✓✓✓
221
L
A
D
F
B
D
226
✓