OPC Comm EIE

The OPC Comm EIE communication device provides a connection between an OPC remote device EIE and an OPC server. The interface allows a user to display and edit data used to identify and configure a connection to an OPC server.

Note: The OPC Comm device can only be paired with the OPC remote device EIE, the OPC Lufkin remote device EIE, or the OPC Weatherford remote device EIE. The devices are non-functional without this exact combination.

See OPCIS vs OPC EIEs for a feature-by-feature comparison of the OPCIS with the OPC EIEs (OPC EIE, OPC Comm EIE, OPC Lufkin EIE, and OPC Weatherford EIE) to help you decide which OPC option best suits the requirements of your enterprise.

OPC Comm EIE Device Editor

A 64-bit version of this EIE is available. See 64-bit Device Drivers.

Properties

The following table lists and describes properties for the OPC Comm Device Editor dialog box.

Property

Description

Device ID

The unique identifier of an instance for this device. This free-form name must be unique in the DDS and the FAC. That is, it must be a name not used by any other communication device, import/export device, remote device, or facility.

CygNet naming standards for device ID are as follows:

Component

Valid Character Set

Limits

Device ID

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z (uppercase)

0 1 2 3 4 5 6 7 8 9

dash (-), underscore (_), and tilde (~).

Note: Tilde (~) is a valid character for both devices and facilities, but its use is not recommended.

20 character maximum

No spaces

Description

A free-form description of the device. 32 character maximum.

OPC server

The name of the OPC server (either the PROGID or CLSID from the registry) with which the comm device is communicating.

Machine name

The OPC_MACHINE_NAME keyword specifies the name of the remote computer on which the OPC server is running. Both UNC (for example, \\SERVER or SERVER) and DNS (for example, server.com or IP address) formats are acceptable.

Note: The machine name may be blank if the server is running on the same machine as the UIS.

Timing

Startup delay (ms)

Specifies the delay time (in milliseconds) to allow an OPC server to initialize before OPC groups are defined. The default value is 0.

Health check rate (ms)

Specifies the rate (in milliseconds) at which the OPC Comm EIE performs a health check of the OPC server. The default value is 1000.

Connection attempt rate (ms)

Specifies the connection attempt rate (in milliseconds) for the OPC Comm EIE to connect with the OPC server. The default value is 60000.

OPC Group Definition

Enable async callbacks

When Enable asynchronous callbacks is selected, the OPC server will perform asynchronous callbacks and push data to the OPC EIE as it retrieves changed values from the remote device.

Update rate (ms)

The value selected for the Update rate (ms) for asynchronous callbacks determines the following behavior:

If asynchronous callbacks are enabled, the Update rate indicates the maximum rate at which the callback should occur, i.e., the OPC server should initiate a callback no more frequently than the update rate.
If asynchronous callbacks are not enabled, the Update rate indicates the minimum rate that the OPC server cache should be updated, i.e., the OPC server should request data from the remote device at least this frequently.

The default value is 60000 milliseconds.

Deadband %

The Deadband % is an OPC standard capability that requests that an OPC server only report value changes that exceed a configured percentage. Type a percentage value for the OPC Group Definition. The default value is 0.

Advanced options

Connection compatibility mode

When selected, the Connection compatibility mode is enabled for the device.

If connection compatibility mode is enabled, every health check will also perform a read from cache for one data item from every group the device is subscribed to, to verify that the OPC connection is still active. This check will keep the connection from becoming inactive thereby reducing disconnect/reconnect occurrences, will detect when connections are lost, and will automatically re-establish the connection and subscriptions when disconnection does occur.

Force synchronous I/O

When selected, synchronous I/0 communication is forced for the device. Select this option if the OPC server does not support asynchronous communication. When set the OPC Comm device will override the value of the SyncIO parameter in the UIS command component parameters for each OPC EIE. See the following:

Enable device

Select whether to enable or disable the device. The default setting is disabled. If an invalid configuration is detected, the device will automatically be disabled. The device can be re-enabled after the invalid configuration is fixed.