Iec 61131-3 Second edition 2003-01 Programmable controllers – Part 3: Programming languages

Table 6 - Two-character combinations in character strings
No.
Combination
Interpretation when printed
2
$$
Dollar sign
3
$'
Single quote
4
$L or $l
Line feed
5
$N or $n
Newline
6
$P or $p
Form feed (page)
7
$R or $r
Carriage return
8
$T or $t
Tab
9
$"
Double quote
NOTE 1
The “newline” character provides an implementation-independent means of defining
the end of a line of data for both physical and file I/O; for printing, the effect is that of
ending a line of data and resuming printing at the beginning of the next line.
NOTE 2
The $' combination is only valid inside single quoted string literals.
NOTE 3
The $" combination is only valid inside double quoted string literals.
2.2.3 Time literals
The need to provide external representations for two distinct types of time-related data is recognized:
duration
data for measuring or controlling the elapsed time of a control event, and time of day data
(which may also include date information) for synchronizing the beginning or end of a control event to
an absolute time reference.
Duration and time of day literals shall be delimited on the left by the keywords defined in 2.2.3.1 and
2.2.3.2.
2.2.3.1 Duration
Duration data shall be delimited on the left by the keyword T# or TIME#. The representation of
duration data in terms of days, hours, minutes, seconds, and milliseconds, or any combination thereof,
shall be supported as shown in table 7. The least significant time unit can be written in real notation
without an exponent.
The units of duration literals can be separated by underline characters.
“Overflow” of the most significant unit of a duration literal is permitted, for example, the notation
T#25h_15m is permitted.
Time units, for example, seconds, milliseconds, etc., can be represented in upper- or lower- case
letters.
As illustrated in table 7, both positive and negative values are allowed for durations.
Copyright International Electrotechnical Commission 
Provided by IHS under license with IEC
Not for Resale
No reproduction or networking permitted without license from IHS
--``````-`-`,,`,,`,`,,`---

---

61131-3 
 IEC:2003(E)
– 29 –