Double-click on the function block to open the function properties table.

The %READ_VAR function block has the following properties:

Property	Value	Description
Used	Activated / deactivated checkbox	Indicates whether the address is in use.
Address	%READ_VARi, where i is from 0 to the number of objects available on this logic controller	i is the instance identifier. For the maximum number of instances, refer to Maximum Number of Objects table.
Symbol	User-defined text	The symbol uniquely identifies this object. For details, refer to the SoMachine Basic Operating Guide (Defining and Using Symbols).
Link	SL1: Serial 1 SL2: Serial 2 ETH1: Ethernet	Port selection NOTE: SL2 and ETH1 embedded communication ports are available on certain controller references only.
Id	This parameter depends on the link configuration: 1...247 for serial lines server address 1...16 for Ethernet index	Device identifier For more details about the Ethernet index, refer to Adding Remote Servers.
Timeout	The unit is in ms, with a default of 100. A value of 0 means no timeout enforced.	The timeout sets the maximum time to wait to receive an answer. If the timeout expires, the exchange terminates in error with an error code (CommError = 01 hex). If the system receives a response after the timeout expiration, this response is ignored. NOTE: The timeout set on the function block overrides the value configured into SoMachine Basic configuration screens (Modbus TCP Configuration and Serial Line Configuration).
ObjType	The type of objects to read: %MW (Mbs Fct 3): memory words (default) %I (Mbs Fct 2): input bits %Q (Mbs Fct 1): output bits %IW (Mbs Fct 4): input words	The types of Modbus read function codes are: Mbs Fct 3: equivalent to Modbus function code 03 Mbs Fct 2: equivalent to Modbus function code 02 Mbs Fct 1: equivalent to Modbus function code 01 Mbs Fct 4: equivalent to Modbus function code 04
FirstObj	0...65535	Address of the first object to read.
Quantity	0...124 for %MW 0...127 for %I 0...127 for %Q 0...124 for %IW	Number of objects to read
IndexData	0...65535	The first address of the word table to which read values are stored (%MW).
Comment	User-defined text	A comment to associate with this object.

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