Read And Write Process Data; Supported Data Types - Siemens SIMATIC S7-1500 Function Manual

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3.20 API (Application Programming Interface)
Limitations for Web API sessions
The CPU limits the number of active sessions. The following table shows the limitations
based on the memory platform used.
CPUs
S7-1510 to S7-1513
S7-1515 and S7-1516
S7-1517 and S7-1518
Limitation of the active Web API sessions
If you request another authentication token and none are available, then the request is
rejected.
Changes to CPU user administration
If the configuration of CPU user management changes (by downloading the HW
configuration in the TIA Portal), e.g. password changed or user removed, the CPU ends all
sessions with a logout event.
Security events
The CPU generates a security event for successful and failed logins. The CPU enters this
security event in the diagnostics buffer.
3.20.5

Read and write process data

3.20.5.1

Supported data types

Binary representation
The Web API presents the values of primitive data types as pure binary data ("raw"). The
binary data is formatted as a JSON array. Each element within an array is a numeric value
between 0 and 255 and represents a single data byte.
Simple display ("simple")
The Web API formats primitive data types into a readable form while preserving the ability to
process the data using a program. The following section describes how primitive data types
are represented as JSON data type.
170
Limitation
50
100
200
Function Manual, 11/2019, A5E03484625-AG
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