Yokogawa DX Serial Driver
writes; the server automatically fails any write request received from a client and does not post a message
to the Event Log.
Device Properties — Tag Generation
The automatic tag database generation features make setting up an application a plug-and-play operation.
Select communications drivers can be configured to automatically build a list of tags that correspond to
device-specific data. These automatically generated tags (which depend on the nature of the supporting
driver) can be browsed from the clients.
Not all devices and drivers support full automatic tag database generation and not all support the same data
types. Consult the data types descriptions or the supported data type lists for each driver for specifics.
If the target device supports its own local tag database, the driver reads the device's tag information and
uses the data to generate tags within the server. If the device does not natively support named tags, the
driver creates a list of tags based on driver-specific information. An example of these two conditions is as
follows:
1. If a data acquisition system supports its own local tag database, the communications driver uses the
tag names found in the device to build the server's tags.
2. If an Ethernet I/O system supports detection of its own available I/O module types, the
communications driver automatically generates tags in the server that are based on the types of I/O
modules plugged into the Ethernet I/O rack.
Note
: Automatic tag database generation's mode of operation is completely configurable. For more
information, refer to the property descriptions below.
On Property Change
: If the device supports automatic tag generation when certain properties change, the
On Property Change
option is shown. It is set to
Yes
by default, but it can be set to
No
to control over when
tag generation is performed. In this case, the
Create tags
action must be manually invoked to perform tag
generation.
On Device Startup
: This property specifies when OPC tags are automatically generated. Descriptions of the
options are as follows:
l
Do Not Generate on Startup
: This option prevents the driver from adding any OPC tags to the tag
space of the server. This is the default setting.
l
Always Generate on Startup
: This option causes the driver to evaluate the device for tag
information. It also adds tags to the tag space of the server every time the server is launched.
l
Generate on First Startup
: This option causes the driver to evaluate the target device for tag
information the first time the project is run. It also adds any OPC tags to the server tag space as
needed.
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