Protocols and Field Devices

Note

For step-by-step instructions on adding a field device, see Adding a Field Device.

Siemens S7OPC UAModbus TCP

Supported controller families:

• S7-300 / S7-400
• S7-1200 / S7-1500 (TIA Portal, symbolic and absolute addressing)

Address formats for manual entry

When variables are entered manually via the UI or imported via CSV, the following address formats apply.

Absolute addressing

Structure: DB<Nr>.DB<B|W|D|X><ByteOffset>.<BitOffset>

• The operand type (DBB, DBD, DBX, DBW) can be used interchangeably — it is for readability only
• The bit offset is optional and may be omitted together with the separating period
• Spaces must be removed

Examples: DB9.DBX200.2 (bit 2 of byte 200 in DB 9), DB30.DBW558 (byte 558 in DB 30)

Symbolic addressing

Structure: PLC.Blocks.<DataBlock>.<Variable>, always starting with PLC.Blocks.

• Names containing a period must be enclosed in double quotes: “My.Name”
• A double quote inside a name is escaped by doubling it: “My""Name”
• Case-sensitive

Examples: PLC.Blocks.TestDB.MyVariable, PLC.Blocks.TestDB."My.Structure".MyVariable, PLC.Blocks.TestDB.Array.Element[28]

Note

Invalid addresses — common with manual entry — silently prevent data access. Using the import function avoids this: variables are correctly formatted and escaped automatically.

Supported data types

Edge VarType	Edge InfluxType	Bits	Symbolic	Absolute	S7-300/400	S7-1200	S7-1500
Binary numbers
S7_Bool	FLOAT	1
S7_Byte	FLOAT	8
S7_Word	FLOAT	16
S7_DWord	FLOAT	32
S7_LWord	FLOAT	64
Integers
S7_SInt	FLOAT	8
S7_Int	FLOAT	16
S7_DInt	FLOAT	32
S7_USInt	FLOAT	8
S7_UInt	FLOAT	16
S7_UDInt	FLOAT	32
S7_LInt	FLOAT	64
S7_ULInt	FLOAT	64
Floating-point numbers
S7_Real	FLOAT	32
S7_LReal	FLOAT	64
Times
S7_S5Time	STRING	16
S7_Time	STRING	32
S7_LTime	STRING	64
Date and time
S7_Date	STRING	16
S7_Time_Of_Day	STRING	32
S7_LTOD	STRING	64
S7_Date_And_Time	STRING	64
S7_LDT	STRING	64
S7_DTL	STRING	96
Characters
S7_Char	STRING	8
S7_WChar	STRING	16
S7_String	STRING	n+2 bytes
S7_WString	STRING	n+2 words
Arrays
S7_Array					(max 6 dims, 32,767 bytes)	(max 6 dims, 65,535 bytes)	(max 6 dims, 16,777,216 bytes)
Pointers
Pointer		48
Any		80
Variant		0

OPC UA is supported for reading measured values from OPC UA servers. Full feature support is currently guaranteed for Siemens OPC UA servers.

Property	Value
Protocol	OPC UA
Default port	4840 (configurable in PLC project)
Authentication	Anonymous or username / password

Property	Details
Supported functions	READ_COIL, READ_DISCRETE_INPUT, READ_INPUT_REGISTER, READ_HOLDING_REGISTER
Default port	502
Slave ID (Modbus RTU)	Configurable; default = 1
Byte order	Big-endian or little-endian (default); applies to data types larger than 16 bits

Note

Byte order cannot currently be configured in the UI. Contact support if a non-default byte order is required.

Supported data types

Data type	Notes
BOOLEAN	Bit-level access only (READ_COIL, READ_DISCRETE_INPUT)
INT16
UINT16
INT32
UINT32
INT64
UINT64
FLOAT
DOUBLE
STRING	8 characters by default; contact support for a different length