4 Step Ladder Instructions 7. Restrictions on Using Some Instructions: The program of every step is the same as a general ladder diagram, in which you can use all kinds of series/parallel circuits or instructions. However, there are restrictions on some of the instructions. Basic instructions applicable in a step DO NOT use MC/MCR instruction in the step. DO NOT use STL instruction in a general subroutine or interruption subroutine. You can still use CJ instruction in STL instruction, but this will make the actions more complicated. We do not recommend you do so. The position of MPS/MRD/MPP instruction: Ladder diagram: Instruction code: STL Sn Explanation:
MPS/MRD/MPP instruction cannot LD X0 LD X0 be used directly on the new bus. Y1 S S n X1 X0 MPS MPS You have to execute LD or LDI X2 AND X1 instruction first before applying BUS MRD X3 M0 OUT Y1 MPS/MRD/MPP. Y2 MRD MPP AND X2 OUT M0 MPP AND X3 OUT Y2 DVP-PLC Application Manual 4-8 Instruction LD/LDI/LDP/LDF AND/ANI/ANDP/ANDF ANB/ORB MC/MCR OR/ORI/ORP/ORF MPS/MRD/MPP Step INV/OUT/SET/RST Initial step/general step Yes Yes No Divergence/ convergence step General output Yes Yes No Step transfer Yes No No