Device-Specific System Items

$SYS$Status

Boolean/

Read

Binary status indication of the connection state to the device (hierarchy level) the item is attached to. The device group (OPC access path/topic) does not affect the value.

The status can be good even if individual items have errors.

For DDE/SuiteLink clients, $SYS$Status always comes from the leaf level of a gateway hierarchy branch, which is the destination data source.
For OPC clients, $SYS$Status can be accessed at all hierarchy levels. $SYS$Status at the root level of the whole hierarchy tree is always good, as it represents the quality status of the local computer itself. Hence, for practical application, OPC clients should reference $SYS$Status at any hierarchy levels other than the root.

RANGE: 0, 1

1: Gateway connection to the data source is intact.

0: Error communicating with the data source.

$SYS$ErrorCode

Longint/

Read

Detailed error code of the communications state to the data source.

The device group (OPC access path/topic) does not affect the value.

>= 0: Good status (0 is the default state – connected.

>0: is some state like: connecting, initializing, etc.

<0: Error status (value indicates the error).

$SYS$ErrorText

String/

Read

Detailed error string of the communications state of the data source.

The device group (OPC access path/topic) does not affect the value.

Descriptive text for the communications state corresponding to the error code.

$SYS$StoreSettings

Integer/ Read Write

Not used.