You're currently browsing the Ignition 8.0 docs. Click here to view the latest docs.

The following feature is new in Ignition version 8.0.0
Click here to check out the other new features
This function is used in Python Scripting.

Description

Reads the value of the Tags at the given paths. Will "block" until the read operation is complete or times out. Meaning, execution of the calling script will pause until this function finishes. This useful in cases where the tag read must complete before further lines in the same script should execute. 

Client Permission Restrictions

This scripting function has no Client Permission restrictions.

Syntax

system.tag.readBlocking(tagPaths, timeout)

  • Parameters

List tagPaths - A List of Tag paths to read from. If no property is specified in a path, the Value property is assumed.

Integer timeout -  How long to wait in milliseconds before the read operation times out. This parameter is optional, and defaults to 45000 milliseconds if not specified. [optional]    

  • Returns

List - A list of QualifiedValue objects corresponding to the Tag paths. Each qualified value will have three sub members: value, quality, and timestamp.

  • Scope

Gateway, Vision Client, Perspective Session

Code Examples
Code Snippet - Read From Multiple Tags
# Specify the paths
paths = [
			"[default]Folder/Tag_A",
			"[default]Folder/Tag_B"
		]

# Send the reads off
values = system.tag.readBlocking(paths)

# Here we can examine each value
for i in range(len(values)):
	print "Tag at Path: %s\n Had a value of %s" % (paths[i], values[i].value)
Keywords

system tag readBlocking, tag.readBlocking

  • No labels