addm: Convert a String into an Address

Function Description

The ADDM function block converts a destination address that is represented as a string to an ADDRESS structure. You can use the ADDRESS structure as an entry in a communication function block.

Graphical Representation

`ADDM` - Specific Parameter Description

Input/Output	Type	Comment
`AddrTable`	ADDRESS	This is the ADDRESS structure to be filled by the function block.

Input	Type	Comment
`Execute`	BOOL	Executes the function at the rising edge.
`Addr`	STRING	Address in STRING type to be converted in ADDRESS type (see details below).

Output	Type	Comment
`Done`	BOOL	`Done` is set to `TRUE` when the function is completed successfully. NOTE: When the operation is aborted with the Abort input, Done is not set to 1 (only `Aborted`).
`Error`	BOOL	`Error` is set to `TRUE` when the function stops due to detection of an error. When there is a detected error, `CommError` and `OperError` contain information about the detected error.
`CommError`	BYTE	`CommError` contains communication error codes.

NOTE: A rising edge on the Execute input executes the conversion and returns an immediate update of AddrTable. However, AddrTable retains the last value when an error is detected (that is when the Addr string is not correct).

Function blocks require a rising edge in order to be initiated. The function block needs to first see the Execute input as FALSE in order to detect a subsequent rising edge.

WARNING
	UNINTENDED EQUIPMENT OPERATION Always make the first call to a function block with its `Execute` input set to `FALSE` so that it may detect a subsequent rising edge. Failure to follow these instructions can result in death, serious injury, or equipment damage.

Addr STRING for ASCII Address Format

For ASCII addressing, only the communication port number is requested:

'<communication port number>'

For example, to send a user-defined message on serial line 2, use the string '2'.

This table defines the fields in the ADDM output for the ASCII address format:

Field	Type	Value	Example
`_Type`	BYTE	Reserved	Not used
`_CliID`	BYTE	Reserved	Not used
`Rack`	BYTE	Rack number (always 0)	0
`Module`	BYTE	Module number (always 0)	0
`Link`	LinkNumber	`<communication port number>`	2
`_ProtId`	BYTE	Not used	Not used
`AddrLen`	BYTE	0	0
`UnitId`	BYTE	Not used	Not used
`AddrExt`	ADDR_EXT	Not used	Not used

Addr STRING for Modbus TCP Address Format

Address of a Modbus TCP Standard Slave

For the Modbus TCP standard slave address format, the communication port number (3 for the embedded Ethernet port) and the destination IP address are requested:

'<communication port number>{<IP address>}'

NOTE: A Modbus TCP standard slave uses Modbus address 255 (the UnitId default value). However, a Modbus TCP device may have different value (for example, a TeSys has Modbus address 1). In this case, add the UnitId value:

'<communication port number>{<IP address>}<UnitId>'

TCP port 502 is used by default. It is possible to use a non-standard port by adding the requested port number to the IP address:

'<communication port number>{<IP address>:<port>}'

For example, to send a message at Modbus TCP slave IP address 192.168.1.2 using standard TCP port 502, use this string: '3{192.168.1.2}'

The ADDM function fills the AddrTable input/output with these values:

Field	Type	Value	Example
`_Type`	BYTE	Reserved	Not used
`_CliID`	BYTE	Reserved	Not used
`Rack`	BYTE	Rack number	0
`Module`	BYTE	Module number	0
`Link`	LinkNumber	`<communication port number>`	3
`_ProtId`	BYTE	0 for Modbus	0
`AddrLen`	BYTE	`UnitID + AdrExt` length in bytes	7
`UnitId`	BYTE	Modbus address (255 by default)	255
`AddrExt`	TCP_ADDR_EXT	A	192
		B	168
		C	1
		D	2
		<port> (default = 502)	502

Address of a Modbus Serial Slave Through Ethernet/Serial Line Gateway

It is also possible to address a Modbus slave through an Ethernet/serial line gateway:

The request includes the communication port number, gateway IP address with or without TCP port), and the Modbus serial slave address (UnitId parameter):

'<communication port number>{<IP address>}<slave address>'

For example, to send a message at Modbus Serial slave address 5 through a Ethernet/serial line gateway at IP address 192.168.1.2 using standard TCP port 502, use this string: '3{192.168.1.2}5'

The ADDM function fills the AddrTable input/output with these values:

Field	Size	Value	Example
`_Type`	BYTE	Reserved	Not used
`_CliID`	BYTE	Reserved	Not used
`Rack`	BYTE	Rack number	0
`Module`	BYTE	Module number	0
`Link`	LinkNumber	`<communication port number>`	3
`_ProtId`	BYTE	0 for Modbus	0
`AddrLen`	BYTE	`UnitID + AdrExt` length in bytes	7
`UnitId`	BYTE	<Slave address>	5
`AddrExt`	TCP_ADDR_EXT	A	192
		B	168
		C	1
		D	2
		TCP port number (default = 502)	502

Example

This example shows the implementation of the ADDM function block in conjunction with the SINGLE_WRITE function block. The ADDM function block converts the given STRING '1.8' to the variable stSlave8OnSL1 of type ADDRESS. If the conversion was successful the input Execute of subsequent function block SINGLE_WRITE is triggered.

ADDM: Convert a String into an Address