The OPC identifier of a CygNet point is its fully qualified tag string. You can use one of the CygNet tag string formats. You can use CygNet Explorer to view the tag strings. In the PNT view, you can right-click on a point and copy its tag string to the clipboard.
See Optional Site.Service Specifier in OPC Identifier for information about omitting the Site.Service specifier from the OPC identifier.
By default, the CygNet OPC Server will return the value of a point. You can define a specific property to return by appending the property to the tag string using a semicolon.
TagString;Property
Example
|
MYSITE.UIS::MESA1234.PDIFF;ALARMACK |
This example returns the alarm acknowledgment status of the MESA1234 differential pressure point.
The available properties are listed in the tables below.
| OPC Property | Description |
|---|---|
|
ACCESSRIGHTS |
Item Access Rights |
|
DESCRIPTION |
Item Description |
|
QUALITY |
Item Quality |
|
SCANRATE |
Server Scan Rate |
|
TIMESTAMP |
Item Timestamp |
|
UNITS |
Engineering Units |
|
VALUE |
Item Value |
|
VALUETYPE |
Item Canonical Data Type |
| OPC Property | Description |
|---|---|
|
ALARMACK |
Alarm acknowledgment state (0=unacknowledged; 1=acknowledged; 2=no alarm) |
|
COMMENTS |
The point’s comments (PNT property) |
|
FACILITY |
The point’s facility (PNT property) |
|
FULLTAG |
CygNet Full Tag (SITE.SERVICE.POINTID:LONGID) |
|
LONGPOINTID |
Long Point ID |
|
LONGTAG |
CygNet Long Tag (SITE.SERVICE:LONGID) |
|
POINTID |
Point ID |
|
SERVICE |
The point’s current value service |
|
SITE |
The point’s site |
|
SITESERVICE |
The point’s site and current value service (MYSITE.UIS) |
|
STATUS |
The CygNet status of the point (real-time record property) |
|
SYSTEM |
The point’s system (PNT property) |
|
TAG |
CygNet Tag (SITE.SERVICE.POINTID) |
|
UDC |
The point’s UDC (PNT property) |
|
USERSTATUS |
User-defined status (real-time record property) |
|
|
|
