Node Types

CONNECT I/O has five different types of nodes, Inputs, Outputs, Memories, Sources and Nodes:

Inputs Values read from HOME I/O (e.g. light switch is on or off).
Outputs Values written to HOME I/O (e.g. turn a ceiling light on or off).
Memories Generic values exchanged with the simulation (read/write). For example, if the simulation is running, the current simulation date and time, etc.
Sources Nodes for generating values (e.g. a Boolean, integer, float, string, etc.).
Nodes Nodes providing functionalities (e.g. arithmetic operations, counters, connectivity with PLC and interface boards, etc.).

Inputs, Outputs, Memories

The first three types, Inputs, Outputs, and Memories, are tied together with HOME I/O and their names give you an idea of their purpose. To better understand these nodes, it helps to think of CONNECT I/O as a controller (much like a PLC or microcontroller). Inputs are used to read values, outputs to write values and memories to read or write values to or from the simulation.

Data Types

Input, output, memory and source nodes can hold values of different data types. The following table shows all the supported data types, equivalent IEC61131-3 and range.

Data Type Range IEC61131-3 Notes
Bit True or False BOOL -
Byte 0 to 255 BYTE -
Short -32,768 to 32,767 SINT -
Int -2,147,483,648 to 2,147,483,647 INT -
Long -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 DINT -
Float -3.403 x 1038 to 3.403 x 1038 REAL -
Double ±5.0 × 10−324 to ±1.7 × 10308 LREAL -
String 64 UNICODE Characters STRING -
DateTime 00:00:00, January 1, 0001 through 23:59:59, December 31, 9999 DATE_AND_TIME Represents an instant in time, typically expressed as a date and time of day.
Timespan -10675199.02:48:05.4775808 to 10675199.02:48:05.4775807 N/A Represents a time interval that is measured as a positive or a negative number of days, hours, minutes, seconds, and fractions of a second.


Besides a value, each input, output, and memory have an address and name. The address is used to define where the value is stored, while the name helps to identify the node's value without having to keep track of the address. It's much easier to use names than numbers to identify a node. Commonly, when an I/O (input/output) and a name is grouped together it's called a tag. On the Nodes Palette, you can find a panel called Tags where all the simulation I/O points (with a name!) are automatically detected and have the name and address already set.

Note that Inputs, Outputs and Memories have an address range per data type. Bit address range is from 0 to 512 while for other data types is from 0 to 256.


Sources nodes generate values of any data type. Typically, these nodes are used upstream in the diagram and the generated values are set by the user.

BIT Boolean value, click to toggle on/off.
Name: use it to describe this node.
NUMERICAL Numerical value (byte, short, int, long, float or double). The value type is determined by the downstream socket to which it is linked to. For example, if the downstream socket requires an integer value, it will be cast to an integer. You set the value by typing it in the input field or by dragging the slider.
Name: use it to describe this node.
Max: maximum possible value.
Min: minimum possible value.
STRING Represents a string. Set the string value by typing it on the Value property.
Name: use it to describe this node.
Value: the string value.
DATETIME A date and time value.
Name: use it to describe this node.
SYSTEM TIME The current system (computer) date and time.
CYCLE TIME The diagram cycle time in milliseconds, i.e. the time it takes to update the diagram.