The data type prefix identifies the data type of variables and constants.
NOTE: The data type prefix can also be composite, for example, for pointers, references and arrays. The pointer or array is listed first, followed by the prefix of the pointer type or array type.
The IEC 61131-3 standard data type prefixes as well as the prefixes for the extensions to the standard are listed in the table.
|
Data type prefix |
Type |
Use (memory location) |
Example |
|---|---|---|---|
|
x |
BOOL |
boolean (8 bit) |
xName |
|
by |
BYTE |
bit sequence (8 bit) |
byName |
|
w |
WORD |
bit sequence (16 bit) |
wName |
|
dw |
DWORD |
bit sequence (32 bit) |
dwName |
|
lw |
LWORD |
bit sequence (64 bit) |
lwName |
|
si |
SINT |
short integer (8 bit) |
siName |
|
i |
INT |
integer (16 bit) |
iName |
|
di |
DINT |
doubled integer (32 bit) |
diName |
|
li |
LINT |
long integer (64 bit) |
liName |
|
uli |
ULINT |
long integer (64 bit) |
uliName |
|
usi |
USINT |
short integer (8 bit) |
usiName |
|
ui |
UINT |
integer (16 bit) |
uiName |
|
udi |
UDINT |
doubled integer (32 bit) |
udiName |
|
r |
REAL |
floating-point number (32 bit) |
rName |
|
lr |
LREAL |
doubled floating-point number (64 bit) |
lrName |
|
dat |
DATE |
date (32 bit) |
datName |
|
t |
TOD |
time (32 bit) |
tName |
|
dt |
DT |
date and time (32 bit) |
dtName |
|
tim |
TIME |
duration (32 bit) |
timName |
|
ltim |
LTIME |
duration (64 bit) |
ltimName |
|
s |
STRING |
character string ASCII |
sName |
|
ws |
WSTRING |
character string unicode |
wsName |
|
p |
pointers |
pointer |
pxName |
|
r |
reference |
reference |
rxName |
|
a |
array |
field |
axName |
|
e |
enumeration |
list type |
eName |
|
st |
struct |
structure |
stName |
|
if |
interface |
interface |
ifMotion |
|
ut |
union |
union |
uName |
|
fb |
function block |
function block |
fbName |
piCounter: POINTER TO INT;
aiCounters: ARRAY [1..22] OF INT;
paiRefCounter: POINTER TO ARRAY [1..22] OF INT;
apstTest : ARRAY[1..2] OF POINTER TO ST_MotionStructure;
rdiCounter : REFERENCE TO DINT;
ifMotion : IF_Motion;
