Toshiba T2N User Manual download pdf (Page 220)

5. Programming Language

User's manual 207

The general facts required for designing programs with ladder diagrams

are listed below.

(1) In all program types, it is necessary to create at least one block

by ladder diagram. In other words, the ends of the main program

and each sub-program are judged by ladder diagram END

instruction. Also, the end of each interrupt program is judged by a

ladder diagram IRET instruction. Furthermore, it is necessary to

compose the entry to and exit from a sub-routine by the ladder

diagram SUBR instruction and RET instruction.

(2) The group of instructions which includes the timer instructions (4

types), counter instruction, jump control instruction, master

control instruction and END instruction in the relay symbol type

instructions is called the ‘basic ladder instructions’.

(3) Instructions other than the basic laddeer instructions are called

‘function instructions’. The function instructions have respective

individual function numbers (FUN No.). Also, even if instructions

have the same function number, selection of the execution

conditions is possible as shown below. (There are some

instructions which cannot be selected)

Normal ... Executed every scan while the instruction input is ON.

Edged ... Executed only in the scan in which the instruction

input changes from OFF to ON.

Example) Data Transfer Instruction

Any instructions cannot be positioned after (to the right of) a

edged function instruction.

Example)

General Information on

Ladder Diagram

Instructions

Normal

The MOV instruction (substitute 10 in D1000) is executed only in the scan in

which R0000 changes from OFF to ON.

Neither of these two rung can be created.

Edged

The MOV instruction (substitute 10 in D1000) is executed every scan while

R0000 is ON.

Edged symbol

1 2 ... 215 216 217 218 219 220 221 222 223 224 225 ... 271 272

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Toshiba T2N User Manual Page 220