Siemens MindConnect IoT2040 - Page 44

Data type Length Date range
Bool 1 bit True to False
Byte (unsigned) 1 byte 0 to 255
Word (unsigned) 2 bytes 0 to 65.535
DWord (unsigned) 4 bytes 0 to 4294967295
Char (signed) 1 byte
−128 to 127
Int (signed) 2 bytes
−32768 to 32767
DINT (signed) 4 bytes
−2147483648 to 2147483647
Real 4 bytes +/-1,18e-38 to +/-3.40e+38
String 1- 254 bytes
Offset
Variable types must have an offset. Offset is the starting byte number.
E.g. DW4 (a double word starting from byte 4)
String
Data type
Length
in
bytes
Format
STRING[n]
or
STRING
n+2
ASCII character of any length. n specifies the length of the character string. A
maximum length of 254 characters is permitted. If no length is specified, the
default setting is 254 characters.
Data type Examples of format used
STRING[2] 'AB'
STRING[55] 'The character string can consist of up to 55 characters'
You must enclose your character string in single quotation marks.
The following example shows the byte order when specifying the datatype STRING[4] with the
output value 'AB'.
Configuring protocols
4.2 Overview of S7 protocol for MindConnect IoT2040
MindConnect IoT2040
System Manual 8/2023 44