4 Step Ladder Instructions b) Structure of alternative divergence When the individual condition at the current status is true, the step will be transferred to another individual step. See the diagrams below. When X0 = On, S20 will be transferred to S30; when X1 = On, S20 will be transferred to S31; when X2 = On, S20 will be transferred to S32. Ladder diagram: S20 X0 SFC: S20 S X1 X0 X1 X2 X2 S30 S31 S32 c) Structure of the simultaneous convergence See the ladder diagram below. A continuous STL instruction represents a simultaneous convergence. When the condition is true after a continuous output, the step will be transferred to the next step.
In the simultaneous convergence, only when several conditions are true will the transfer be allowed. Ladder diagram: SFC: S S40 S S41 S S42 X2 S40 S41 S42 X2 S50 d) Structure of alternative convergence See the diagrams below. Depending on the condition of the input signal of which of S30, S40 and S50 becomes true first, the first one will be first transferred to S60. Ladder diagram: SFC: S30 X0 S S40 S X1 S30 S40 S50 X0 X1 X2 S S50 X2 S60 DVP-PLC Application Manual 4-13 SET S30 SET S31 2 SET S32 SET S50 SET S60 1 SET S60 2 SET S60