GSK218M CNC System Connection and PLC Manual
32
4 PLC Basic Instruction
Desigining a sequence program begins with writing a ladder diagram. The ladder diagram is
written using relay contact symbols and functional instruction code. Logic written in the ladder
diagram is entered as a sequence program in the Programmer. There are two sequence program
entry methods. One is the entery method with the mnemonic language(PLC instructions such as
RD, AND, OR). The other is the relay symbols of the ladder diagram.When the relay symbol
method is used, the ladder diagram format can be used and programming can be performed
without understanding the PLC instruction format.
Actually, however, the sequence program entered by the relay symbol method is also internally
converted into the instruction corresponding to the PLC instruction.
The basic instructions are often used when the sequence program is designed, and thet execute
one-bit operation.
GSK218M basic instructions are as follows:
Instruction Function
RD Shifts left the conten by one bit in register and sets the state of a
specified signal in ST0.
RD.NOT Shifts left the content by one bit in register and sets the logic state
of a specified signal in ST0.
WRT Outputs the results of logic operation to a specified address.
WRT.NOT Inverts the results of logical operations and output it to a specified
address.
AND Induces a logical product.
AND.NOT Inverts the state of a specified signal and induces a logical
product.
OR Indues a logical sum.
OR.NOT Inverts the state of a specified signal and induces a logical sum.
OR._STK Sets the logical sum of ST0 and ST1, and shifts the stack register
right by one bit.
AND.STK Sets the logical product of ST0 and ST1, and shifts the stack
register right by one bit.
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