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→assignment of an →initial value in the context of a declaration of variables
You can initialize internal →variables, →input variables, →output variables and →global variables within the declaration of a →program, of a →function block or of a →function.
The expression on the right side of the assignment operator ":=" may be a
→constant expression
(in compliance with the →data type).
Here the most important language constructs that you are able to use:
a Boolean →literal
Possible Boolean literals
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Equivalents for TRUE"
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Equivalents
for "FALSE"
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BOOL#TRUE
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BOOL#FALSE
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BOOL#1
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BOOL#0
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TRUE
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FALSE
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1
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0
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a →bit string literal
Examples for bit string literals
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Description
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Examples
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integer
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0, 123_4, +986
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base 2 (binary literal)
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2#1111_1111 (255 decimal), 2#1110_0000 (224 decimal)
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base 8 (octal literal)
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8#377 (255 decimal), 8#340 (224 decimal)
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base 16 (hexadecimal literal)
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16#FF or 16#ff (255 decimal), 16#E0 or 16#e0 (224 decimal)
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above possibilities as typed literal of type BYTE, WORD, DWORD or LWORD
(if the value is positioned within the range of values for the specific type)
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WORD#986, WORD#16#FF (255 decimal)
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BOOL is a bit string data type. But there are specific →Boolean literals.
an →integer literal
Examples for integer literals
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Description
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Examples
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integer
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-12, 0, 123_4, +986
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base 2 (binary literal)
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2#1111_1111 (255 decimal), 2#1110_0000 (224 decimal)
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base 8 (octal literal)
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8#377 (255 decimal), 8#340 (224 decimal)
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base 16 (hexadecimal literal)
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16#FF or 16#ff (255 decimal), 16#E0 or 16#e0 (224 decimal)
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above possibilities as typed literal of type SINT, INT, DINT, LINT, USINT, UINT, UDINT, ULINT
(if the value is positioned within the range of values for the specific type)
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INT#-12, INT#16#FF (255 decimal)
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a →real literal of data type REAL or LREAL
Examples for real literals
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Description
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Examples
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Real literal
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0, 0.0, 0.4560, 3.14159_26
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Real literal with exponent
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-1.34E-12, -1.34e-12
1.0E+6, 1.0e+6, 1E+6
1.234E6, 1.234e6
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above possibilities as typed literal of type REAL or LREAL
(if the value is positioned within the range of values for the specific type)
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REAL#0.0, REAL#1.0E+6
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a →time literal
Examples for duration literals
You must enter duration data, such as days (d), hours (h), minutes (m), seconds (s) and fractions of a second (ms for milliseconds, us for microseconds, ns for nanoseconds) or any combinations of them, as shown in the following table. You can separate the duration units by underscore character. Moreover, you can enter the units in upper- or lowercase letters, for example s or S for seconds.
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Description
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Examples
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Duration literals without underscore
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Short prefix
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T#14ms, T#14.7s, T#14.7m, T#14.7h, T#14.7d, T#14h12m, t#5d14h12m18s3.5ms
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Long prefix
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TIME#14ms, time#14h12m
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Duration literals with underscore
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Short prefix
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T#14h_12m, t#5d_14h_12m_18s_3.5ms
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Long prefix
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TIME#14h_12m, time#5d_14h_12m_18s_3.5ms
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Observe that your used →target system might influence the usage of duration literals in logi.CAD 3 (see "Properties and restrictions specific to the target system").
Examples for date and time of day literals
In case of date and time literal and time of day literal, the fractions of a second (entered after the .) are optional.
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Description
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Examples
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Date literal
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Short prefix
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D#1984-06-25
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Long prefix
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DATE#1984-06-25
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Date and time literal
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Short prefix
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DT#1984-06-25-15:36:55.360_227_400
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Long prefix
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DATE_AND_TIME#1984-06-25-15:36:55.360227400
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Time of day literal
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Short prefix
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TOD#15:36:55.36
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Long prefix
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TIME_OF_DAY#15:36:55.36
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Observe that your used →target system might influence the usage of these literals in logi.CAD 3 (see "Properties and restrictions specific to the target system").
a →character string literal
Examples for character string literals
Single-byte character strings consist of zero or more characters prefixed and terminated by the single quote character '.
In contrast, logi.CAD 3 does not support double-byte character strings enclosed in the double quote character " for character string literals.
Single-byte character strings are:
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Description
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Examples
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STRING literal
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'OK', 'ABCDEF'
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typed STRING literal
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STRING#'OK', STRING#'ABCDEF'
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CHAR literal
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'B', 'T'
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typed CHAR literal
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CHAR#'B', CHAR#'T'
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This enables you to enter special characters, such as umlauts, for single-byte character string. Currently, such special characters are displayed in logi.CAD 3 (e.g. in the der Values of Variable view) as they have been entered.
Here a selection of special characters (a list of special characters and the corresponding hexadecimal digits is listed under https://www.ascii-code.com/):
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Decimal value
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Hexadecimal digit
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To enter
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Special character
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128
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80
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$80
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€ |
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163
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A3
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$A3
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£ |
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169
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A9
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$A9
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© |
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174
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AE
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$AE
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® |
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177
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B1
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$B1
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± |
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178
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B2
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$B2
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² (superscript "2")
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179
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B3
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$B3
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³ (superscript "3")
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188
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BC
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$BC
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¼ |
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189
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BD
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$BD
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½ |
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190
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BE
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$BE
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¾ |
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196
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C4
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$C4
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Ä
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214
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D6
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$D6
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Ö
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220
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DC
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$DC
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Ü
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223
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DF
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$DF
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ß
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228
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E4
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$E4
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ä |
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246
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F6
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$F6
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ö
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252
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FC
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$FC
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ü
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If the character combination '$00' is assigned to a single character of a STRING variable, the character string of the STRING variable is terminated at this position. Such character strings are terminated in case of $00 in the Values of Variables view as well.
However, the complete character string is copied in assignments. This makes it possible to have the Values of Variables view display single characters behind $00, if you access the assigned characters behind $00.
Moreover, the following specifications are possible for single-byte character strings:
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Specification
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Meaning
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''
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empty string
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' '
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string with space character
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'$''
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string with single quote character '
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'"'
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string with double quote character "
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Moreover, the following specifications are possible for two-character combinations in single-byte character strings:
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Specification
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Meaning
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$'
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string with single quote character '
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$$
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string with dollar sign $
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$L oder $l
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string with line feed
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$N oder $n
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string with newline
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$P oder $p
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string with form feed (page)
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$R oder $r
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string with carriage return
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$T oder $t
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string with tabulator
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a →named element of a data type with named values
structure initialization (initialization of structure elements)
operators (such as +, -, *, /)
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