Python command: OPC

Syntax

Example

Description/Remarks

New or changed in GainSeeker version

opc.host

opc.host = "localhost"

Sets the computer name, IP address, or URL of the OPC server.

opc.isunifiedarchitecture

opc.isunifiedarchitecture = False

OPC server uses the DA specification, not the UA specification.

Gets or sets whether the OPC server uses the Unified Architecture (UA) specification. For an OPC Classic or OPC DA server, this should be set to False.

This is detected and set automatically from the host name, but can be manually set if detected incorrectly. If used, must be set after the opc.host command.

opc.namespaceindex

opc.namespaceindex = 1

May be any number.

Defaults to 0 (0 and negative values are ignored).

Sets the namespace index of the tag to be read. When specifying an index number, the index may be any positive integer (values of 0 or below are ignored).

Alternately, you may use this command to set the namespace URI.

Only used for OPC UA servers.

opc.namespaceuri

opc.namespaceuri = "quality"

Sets the namespace URI of the tag to be read.

Alternately, you may use this command to set the namespace index.

Only used for OPC UA servers.

opc.progid

opc.progid = "Kepware.KEPServer.V5"

For OPC Classic and OPC DA servers, this identifies the OPC server on the host computer.

Not used for OPC UA.

opc.readvalue(tag)

tag1 = opc.readvalue("Machine3.value1")

Returns the value of the specified tag name on the OPC server.

opc.readvalueandquality(tag)

tag1 = opc.readvalueandquality("Machine3.value1")

For the specified tag name, this returns a list of the value for that tag and the quality of this tag's value.

In the returned list, the first element is the value and the second is the quality of that value.

opc.readvalueandqualitylist(taglist)

taglist = ["Machine3.value1","Machine3.value2"]

returnlist = opc.readvalueandqualitylist(taglist)

For the list of specified tag names, this returns a list of value/quality pairs for each tag (in order).

In this returned list, each value/quality pair is a list where the first element is the value and the second is the quality of that value.

opc.readvaluelist(taglist)

taglist = ["Machine3.value1","Machine3.value2"]

returnlist = opc.readvaluelist(taglist)

For the list of specified tag names, this returns a list of the value for each tag (in order).

opc.writevalue(tag, value)

opc.writevalue("Machine3.value1", "0")

Writes the specified value to the specified tag name on the OPC server.