Default UDT type conversion

Default UDT type conversion to JSON

Abstract

Default UDT type conversion to JSON

Essential information

JSON strings are enclosed in quotation marks.
They can be any length, but JSON parsers can typically parse strings that are up to 1MB in length.
JSON Boolean values
JSON dates and times
JSON numbers

S7 IEC data types

The Table 1, “Siemens S7 IEC data types to a default format in JSON” maps Siemens S7 IEC data types to a default format in JSON.

Table 1. Siemens S7 IEC data types to a default format in JSON

S7 data type

JSON type

JSON format

BOOL

Boolean

true

false

BYTE

Integer

255

1

0

WORD

Integer

65535

1

0

DWORD

Integer

4294967296

1

0

INT

Integer

-32768

-1

0

1

32767

DINT

Integer

-2147483648

-1

0

1

2147483647

REAL

Integer

-9999999999

-1.0

-1

0

1

1.0

0.1

0.00000009

S5TIME (duration)

String

S5T#[n]H_[n]M_[n]S_[n]MS — for example, S5T#0H_1M_0S_0MS

TIME (duration)

String

T#[n]D_[n]H_[n]M_[n]S_[n]MS — for example, T#0D_1H_1M_0S_0MS

-T#[n]D_[n]H_[n]M_[n]S_[n]MS — for example, T#24D_24H_31M_23S_647MS

DATE

String

YYYY-MM-DD — for example, 2009-01-06

TIME_OF_DAY

String

hh:mm:ss.sss — for example, 16:01:59.001

CHAR

String

"some string"

Nested Arrays

Array of arrays

{
 "myArray": 
 [ 
   [1,2,3],  
   [4,5,6] 
 ]
}

Array of Values

Array of values

{
 "array1": [ 1,2,3 ],
 "array2": [ "A","B","C" ],
 "array3": [ "A",1, "B",2, "C",3 ]
}

Array of Objects

Array of objects

{
 "myArray": 
 [ 
   { "Label": "height", "Value": 1}  
 ]
}

Note

All of the types listed in Table 1, “Siemens S7 IEC data types to a default format in JSON” have been tested extensively except S5TIME (duration), TIME (duration), DATE, and TIME_OF_DAY. These four types are also supported, but they have not been tested.