represents a logical link to a device.
A device can be any of the following:
The PLC Device Tag
represents a logical link to a device.
A device can be any of the following:
The PLC Device Tag supports the configuration properties of the Alarm Tag plus these properties:
| Property | Type | Version | Description |
|---|---|---|---|
| OutOfService | BOOL | 3.47 |
Whether Fernhill SCADA communicates with, or ignores, the PLC Device.
|
| AlarmSeverity | UINT | 1.5 | The severity of the alarm raised when the PLC device fails. |
| CommCheckInterval | TIME | 2.2 | The interval between communication status checks to the device. See Interval and Offset for information on how Intervals and Offsets define the time of activities. |
| CommCheckOffset | TIME | 2.2 | The offset added to the CommCheckInterval to get the actual time of the communication status check. See Interval and Offset for information on how Intervals and Offsets define the time of activities. |
The CommCheckInterval and CommCheckOffset properties define when the driver checks the communications to the PLC Device. The result of the communication check is used to determine whether the PLC device is offline or online.
See Interval and Offset for information on how to configure scheduled activities.
The PLC Device Tag supports the data properties of the Alarm Tag plus these properties:
| Property | Type | Version | Description |
|---|---|---|---|
| State | UINT | 1.0 | The state of the device |
| StateDescription | WSTRING | 1.0 | The text description of the device state |
| ModelName | WSTRING | 1.9 | The detected model name of the target device |
| CommCheckTimer | TimerStatus | 2.4 | The status of the communication check timer |
The State property can have these values:
| State | Description |
|---|---|
| 0 | Initial state before the driver starts |
| 1 | The channel reference is invalid |
| 2 | The device is not responding |
| 3 | The channel hosting the device is offline |
| 4 | The reply from the device is not in a recognized format |
| 5 | The device responded with an error code |
| 6 | The channel for this device is disconnected or failed |
| 7 | This device is trying to use a channel that is exclusively allocated to another device |
| 8 | The device is offline |
| 9 | A configuration error prevents operation |
| 10 | The PLC Device is out of service. |
| 15 | The device is online and communicating |
The PLC Device Tag supports the tag commands of the Alarm Tag.
The PLC Device Tag builds on the features of these tag types:
The PLC Device Tag is used as a building block for these tag types:
To learn about properties common to all tags.
To learn about abnormal conditions in SCADA applications.
For the meaning of terms used in Fernhill SCADA.