Siemens 1200PLC continuous control program writing

What we are learning together is the continuous control program writing. Before writing the program, we must first create a project, add equipment, save the project, fill in the name and address in the default variable table, and open the "Main[OB1]" in the "PLC Program" to program.

See the figure below for the specific procedure:

When we start the forward rotation I0.0 action, the normally closed contact of I0.0 will be disconnected first. If the reverse coil Q0.1 is outputting at this time, the reverse coil Q0.1 will stop outputting. Then the normally open contact is conducted (all components are the same: the normally closed contact is disconnected first, and then the normally open contact is closed, with a time difference in between), so that the forward output coil Q0.0 outputs, the normally closed contact of Q0.0 is disconnected to form an interlock, and the normally open self-locking contact of Q0.0 is closed to self-lock. The reverse rotation start I0.2 is exactly the opposite of I0.0. Note: We cannot have double coil output in the program, that is, if there is already a Q0.0 coil, the second Q0.0 coil cannot appear in the program. If there is really no way to avoid it in the program, we can use the internal auxiliary relay M to replace it, as shown in the program in the figure below. In the previous program, we only need to control the two coils M0.0 and M0.1 to control Q2.0.

We can comment on the program in the red box in the figure below, or we can click the ellipsis on the right side of the program segment to give our program segment a name to facilitate our subsequent search and understanding of the program.

Next, let’s learn about setting and resetting. The set and reset buttons are on the far right of the favorites bar, and can also be dragged from the “Bit Logic Instructions” on the right.

S stands for set output, and R stands for reset output. Set output can drive "I/Q/M/D/L". In the following program, when our I1.0 is activated, Q1.0 will output. When I1.0 is reset, Q1.0 will keep outputting. Only when we use "R" to reset Q1.0, Q1.0 will stop outputting. Note: Set-reset operation does not count as double coil