PLC ladder programming Instruction control bits

        ① set and reset. When the condition becomes ON”, the set will be put in operation ON”, but not as output (OUT), when the condition becomes OFF”, the reset will not reset on the operation of OFF”. When the condition becomes ON”, the reduction in operation position reset OFF”, but does not output non-directive (OUT NOT), when the condition becomes OFF”, the reset will not reset on the operation ON”. In the following example, no matter how IR00100, IR00100 reset ON” IR20000 will reset when ON”, and can remain ON” until the IR00101 reset ON”. When IR00101 set ON”, the reset IR20000 reset OFF”. Set and

No function code set and reset. From the handheld programmer to enter them as FUN and SET key or FUN and RSET button, followed by the address.


       ② rise differential differential and the falling edge. Rise differential and the falling edge of the so-called differential refers to the input signal front porch and back operations. Rise differential differential command is used to enable and falling in a cycle time of the built-in ON”. In implementing the conditions OFF” to ON”, the rising differential instruction makes a cycle of operation ON”, in the implementation of conditions ON” to OFF”, the falling differential instruction makes a cycle of operation ON”. Both of these instructions requires only one line mnemonics.


Here, in IR00000 to ON”, IR20001 in a cycle will reset ON”. Then perform DIFU (13) 20001, no matter how IR00000, IR20001 will be OFF”. Falling edge differential instruction IR00001 to OFF” after (IR20002 OFF” until this time), the IR20002 will be built in a cycle ON”, and will be implemented in the next DIFD (14) 20002 post OFF”.
Rise differential and the falling edge of differential


       ③ maintain. Use directives to keep based on two perform conditional operations. Doing so will keep the instructions attached to two on the command line. When the first command line execution at the end of the condition for ON”, keep instructions operating position ON”. When the end of the second command line execution as ON”, keep instructions operating position OFF”. Even if it is located in the internal interlocking parts of the program, keeping the operation of the directive will save it to the ON” or OFF” State.
In the example shown in Figure 1-33, when IR00002 is ON” and IR00003 to OFF”, the HR0000 will be set ON”. HR0000 remain ON” until another IR00004 or IR00005 reset ON”. Keep instructions as the others, need more than one command line, the command line in the instruction encoding before they control.
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