13.8. IP Scanner

IP Scanner is an I/O module that detects the presence of a host over the network. It uses the Internet Control Message Protocol (ICMP), Internet Control Message Protocol version 6 (ICMPv6) and Transmission Control Protocol (TCP). The host may be specified by an IPv4 or IPv6 address or a host name, with or without a port number. The ICMP and ICMPv6 uses Echo request and Echo reply messages for the operation of IP Scanner. These are also the protocols that are used in the Ping network utility program.

The following list shows the protocols for different types of addresses or host names.

IPv4 address without a port number : ICMP
IPv4 address with a port number : TCP
IPv6 address without a port number : ICMPv6
IPv6 address with a port number : TCP
Host name without a port number : ICMP or ICMPv6 depending on its resolved IP address
Host name with a port number : TCP

[Note] Note

A host name will first be resolved to its IP address by a name resolution protocol, e.g. Domain Name System (DNS).

Adding a new row in the I/O Driver tab in Project Editor

In the I/O driver tab, a new row should be added. The column entry "Name" is required because it will define the name of the Port. The column entries "Address" and "Interval" are compulsory in the Project Editor. Enter localhost as "Address" and leave default value for "Interval" in order to proceed.

Adding an IP Scanner Group in the I/O Port tab

A new Port with the given name will be created once the new row is saved. Take note that "Port" does not refer to any physical device or hardware. For the IP Scanner configuration, it is only related to the grouping of host names and IP addresses. In the Port tab, specify the "Name", "Timer" and "Driver". The "Timer" value specifies the suggested interval to read each tag value. The lower is the value, the faster is the response to the change in each tag value. Choose "IP Scanner" for "Driver". Users can specify the Time-out value on the right pane. It is the maximum time to wait for a reply from each host in milliseconds. The minimum timeout is 100 ms.

Adding tag names and host names/IP addresses in the IP Scanner Device/Group tab

After saving the row, a new Device will be created. Take note that "Device" does not refer to any physical device or hardware. It is a group of tags. The IP addresses and host names are represented as tags in each group. In other words, the Device is a group of IP addresses and host names. In the Device tab, only three entries are compulsory, which are "Name", "Path" and "Type". "Name" refers to the tag name. Enter the host names or IP addresses in the "Path" entries. Choose "boolean" for "Type". A boolean value of "true" indicates that a host is alive and replies to the request, while a value of "false" shows that a host does not exist or does not reply or the request has timed out.

[Tip] Tip

Users are encouraged to create only one Device (group of IP addresses and host names) for multiple host names and IP addresses. Creating many groups will consume unnecessary computer resources and slow down the systems.

[Note] Note

Turn Input tag attribute to True for Read-Only input tag.