1. OPC UA Client Port: General Tab

Select the General tab in the Port Properties dialog box.

A Protocol
B Description
C Scan rate
D Retry count
E Enable
F Enable stale data
A Protocol

(Read-only) UACLIENT protocol selected when the port was created.

B Description

Explanatory text about the port.

Maximum Length 40 characters
C Scan rate

The basic timer for points monitored from this port.

The rate at which points are polled is a multiple of the Scan Rate.

Configurable units can be set in any of the following units.

  • Ticks (hundredths of seconds)
  • Seconds
  • Minutes
  • Hours

Note: This option is applicable only for polled points.

D Retry count

Note: OPC UA Client does not use this option..

If communication is interrupted, the OPC UA Client will retry to reconnect infinitely.

E Enable

Do one of the following.

Check Enable communications on this port.
Clear Disable communications on this port.
guide: When a port is dynamically disabled, communication to all devices associated to that port will stop.

By default, when the port is dynamically disabled:

  • The associated devices will be marked Down and their associated points will be marked Unavailable.
  • Setpoints and processing of unsolicited data will not be allowed for the associated devices.
Tip: As an alternative to this default action, you can configure a Global Parameter, ALLOW_UPDATE_WHEN_DISABLED, to keep the associated devices alive.

If ALLOW_UPDATE_WHEN_DISABLED is configured, then when the port is dynamically disabled:

  1. The device is not marked Down.
  2. Polling stops.
  3. Setpoints and unsolicited messages will still be processed.
F Enable stale data

Do one of the following.

Check Keep the point available in most circumstances that would have made it unavailable. However the point value will be stale, meaning it is the last known value and may or may not have changed in the device.
Clear Leave the point unavailable in all circumstances the would make it unavailable.
Tip: Use QUALITY.STALE_DATA (Attribute) to report if the point value is stale.

The following table displays a point's availability when events occur and QUALITY.STALE_DATA is configured as on or off.

Point Availability when Stale Data is Configured
Event On
Poll Failure Available
Process Shutdown Available
System Shutdown Not Applicable
Ind. Point Unavailable Available
Out of PTMRP Range Limits Range Bit / Available
DC Sends Device State Available
DynCfg Disable Point/Device Not Applicable