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AVEVA™ Plant SCADA

Virtual Units - Usurp Data Types

  • Last UpdatedAug 04, 2025
  • 2 minute read

Note: The following data types are only recommended for experienced users who are familiar with the terminology and methods associated with the DNP 3.0 protocol.

Address

Plant SCADA Type

DNP3 Type

Description

Unit<x>.
RequestUnitActive.Primary

INTEGER

Request unit active on primary.

No Object

R/W

Writing a ‘1’ to this tag will force the unit be active on the primary I/O server. Writing ‘0’ will force the unit be active on the standby I/O server.

A read returns the last value written to the tag.

This address does not relate to I/O data internal to the device, but relates to data internal to the driver, or an action to be performed by the driver.

Unit<x>.
RequestUnitActive.Standby

INTEGER

Request unit active on standby.

No Object

R/W

Writing a ‘1’ to this tag will force the unit be active on the standby I/O server. Writing ‘0’ will force the unit be active on the primary I/O server.

A read returns the last value written to the tag.

This address does not relate to I/O data internal to the device, but relates to data internal to the driver, or an action to be performed by the driver.

Unit<x>.
UnitActiveState.Primary

INTEGER

Unit active state on primary.

No Object

R/O

Returns 1 if the unit is active on the primary I/O server and 0 if active on the standby I/O server.

This address does not relate to I/O data internal to the device, but relates to data internal to the driver, or an action to be performed by the driver.

Unit<x>.
UnitActiveState.Standby

INTEGER

Unit active state on standby.

No Object

R/O

Returns 1 if the unit is active on the standby I/O server and 0 if active on the primary I/O server.

This address does not relate to I/O data internal to the device, but relates to data internal to the driver, or an action to be performed by the driver.

Unit<x>.
UnitPortState.Primary

INTEGER

True port connection state of primary unit.

No Object

R/O

Useful to check if the port, a unit is on, is connected.

-1 No peer update
0 Port not connected
1 Port connected.

This address does not relate to I/O data internal to the device, but relates to data internal to the driver, or an action to be performed by the driver.

Unit<x>.
UnitPortState.Standby

INTEGER

True port connection state of standby unit.

No Object

R/O

Useful to check if the port, a unit is on, is connected.

-1 No peer update
0 Port not connected
1 Port connected.

This address does not relate to I/O data internal to the device, but relates to data internal to the driver, or an action to be performed by the driver.

Where:

  • x = device address of the real device as specified in the I/O Device's Address field

  • R/O = read only

  • W/O = write only

  • R/W = read or write

See Also

Configuring Variables for Virtual Units

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