220v-260w电加热棒you want to restart the only for power shutdown restart, can appear the phenomenon. It says more about M8002 only at the instant of the boot to create a cycle of pulse make Y0 setting, and after this time you can think it is in a state of power cuts.
3, state element S, stepping contact instructions STL, stepping back to RET
State element S is used to prepare the sequential control commands of a programming element, it can be used to represent each step processing, it has to do with STL stepping sequence control contact instructions. Stepping back instructions RET is used for the end of the step, said state S end of the process, to return to the main program (bus left) instructions. By the students will command input PLC of figure 3, running through the students to observe, come to the conclusion after talking again.220v-260w电加热棒
When the PLC is in the running state, M8002 instantly send a pulse, setting instruction SET activate S0 state element. At this point the STL S0 normally open contacts through. External connected into the Y0 load driven contactor KM1 suck. Timing starts at the same time T0, after 3 s T0 the normally open contacts closed, setting instruction SET activate S20 state element. Activation of S20 is restricted by the T0 normally open contacts, this is known as transfer conditions. Steps only condition is met, S0 to transfer to S20 back, at this time is controlled by a step S0 external contactor disconnect. In the STL S20 normally open contacts connected at the same time, connect to external load contactor KM2 and Y1. This often is the place where students confused, should be pointed OUT that in practice the transfer between two connected steps, if the back of the step is the OUT instruction, in the process of transformation, mean the end of 220v-260w电加热棒