InstrumentTag (Ethernet communications node)

InstrumentTag Length

The InstrumentTag attribute specifies the Ethernet communications node for the PI Point. It must be a valid IP address or hostname. For example, setting the intstument tag attribute to plc3.osisoft.int would specify that the PI Point will be associated with the node plc3.osisoft.int:502 that was configured using the PIModbusE_Configurator tool.

The interface will validate that the InstrumentTag attribute specifies a valid IP address or hostname when loading the PI Point and that is an IP address or hostname that has previously been configured. The rules for validation are described in the following sections.

Depending on the version of the PI API and the Data Archive, this interface supports an InstrumentTag attribute whose length is at most 32 or 1023 characters.

If the Data Archive version is earlier than 3.4.370.x or the PI API version is earlier than 1.6.0.2, and you want to use a maximum InstrumentTag length of 1023, you need to enable the PI SDK.

IP Address

The supported IP address (Internet Protocol address) is what is known as Internet Protocol Version 4 or IPv4. It is represented in dot-decimal notation (four parts, each one a number ranging from 0 to 255, separated by dots). The following are the requirements of a valid IP address for this interface:

• It must be in the form xxx.xxx.xxx.xxx in which the four parts are separated by periods (i.e., dots).

• Each part xxx must contain only decimal digit characters '0' through '9'.

• Each part xxx must represent a number from 0 to 255.

• No part with more than 1 digit character can have a leading zero character. Although a valid IP address can have a leading zero in a part, networks will treat parts with leading zeros as either octal numbers or as being invalid (if any of the other digits are 8 or 9). To ensure that all PI Points for a given address use the same format, the interface will disallow IP addresses with octal parts.

Hostname

The supported hostname consists of a series of one or more labels concatenated with dots (just as domain names are). It is represented by either a single label or multiple labels in dot-decimal notation (two or more labels, each one separated by dots). The following are the requirements of a valid hostname for this interface:

• It must be in the form xxx or xxx.xxx.[…].xxx in which each label is separated by periods (i.e., dots).

• Each label xxx must contain only ASCII characters 'a' through 'z' (in a case-insensitive manner), the digit characters '0' through '9', the hyphen (‐) character and the underscore (_) character.

• Each label xxx cannot begin or end with either the hyphen (‐) character or the underscore (_) character.

• Each label xxx must be between 1 and 63 characters in length.

• The entire hostname may contain of no more than 8 labels.

• The entire hostname (including the delimiting dots) can be no more than 255 characters in length.

  Note: The use of the underscore character is non-standard but is allowed because it is often used in hostnames in Microsoft Windows systems.