Chapter 5 Instruction Specifications

Item number

Basic instructions-9

Name

Trailing edge detection (AND DFN, OR DFN)

 

 

 

 

 

 

Ladder format

Condition code

Processing time (s)

Remark

 

DFN n

DFN n

 

R7F4

R7F3

R7F2

R7F1

R7F0

Average

Maximum

 

 

DFN n

DFN n

 

 

DER

ERR

SD

V

 

C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

z

z

z

z

 

z

 

 

 

 

 

Instruction format

 

 

 

Number of steps

 

 

1.0

 

 

 

AND DFN n

 

 

 

Condition

 

Steps

 

 

 

 

 

 

OR

DFN n

 

 

AND DFN n

3

 

 

 

 

 

 

 

 

 

 

 

 

OR DFN n

 

4

 

 

 

 

 

 

 

 

 

 

 

Bit

 

Word

 

 

Double word

Constant

 

 

Usable I/O

 

 

R,

TD, SS,

 

WR,

 

 

DR,

Other

 

X

Y

M

CU, CT

WX WY WM

TC

DX DY

DM

n

Number

 

 

 

 

 

 

 

 

 

 

 

{ 0 to 511 (Decimal)

 

Function

 

 

 

 

 

 

 

 

 

 

 

 

 

Detects the fall of an input signal and retains the operation result only for one scan. ( ) indicates the display when the Ladder Editor is used.

Notes

DFN number may not be overlapped. (However, no error is generated even if overlapped numbers are used.)

DFN cannot use the b contact.

Program example

X00000

DFN0

R124

LD

X00000

AND DFN0

OUT R124

Program description

Time chart

X0

R124

1 scan time

Upon a fall of X00000, R124 turns on only for one scan.

If b-contact is used for X00000, operation will be the same as the a-contact DIF operation.

AND DFN n OR DFN n

5-19

Page 69
Image 69
Hitachi NJI-350B manual Basic instructions-9, Trailing edge detection and DFN, or DFN, DFN n