# Tag Parameters

### Value Parameter

Each Tag has a Value Parameter which acts as the Tag’s value for evaluating alarm conditions. All parameter types can be trended and data logged, but this is usually the default value for those features.

### High High Limit Parameter

Each Tag has a High High Limit Parameter which acts as the Tag’s High High Alarm Limit for evaluating alarm conditions from the Value Parameter.  If the value of the Value Parameter exceeds the High High Limit the Tag is considered to be in a High High alarm condition.

### High Limit Parameter

Each Tag has a High Limit Parameter which acts as the Tag’s High Alarm Limit for evaluating alarm conditions from the Value Parameter.  If the value of the Value Parameter exceeds the High Limit the Tag is considered to be in a High alarm condition.

### Low Limit Parameter

Each Tag has a Low Limit Parameter which acts as the Tag’s Low Alarm Limit for evaluating alarm conditions from the Value Parameter.  If the value of the Value Parameter exceeds the Low Limit the Tag is considered to be in a Low alarm condition.

### Low Low Limit Parameter

Each Tag has a Low Low Limit Parameter which acts as the Tag’s Low Low Alarm Limit for evaluating alarm conditions from the Value Parameter.  If the value of the Value Parameter exceeds the Low Low Limit the Tag is considered to be in a Low Low alarm condition.

### Digital Limit Parameter

Each Tag has a Digital Limit Parameter which acts as the Tag’s Digital Alarm Limit for evaluating alarm conditions from the Value Parameter.  If the value of the Value Parameter equals the Digital Limit the Tag is considered to be in a Digital alarm condition.

### Rate of Change Limit Parameter

Each Tag has a Rate of Change Limit Parameter which acts as the Tag’s Rate of Change Alarm Limit for evaluating alarm conditions from the Value Parameter.  If the value of the Value Parameter changes by more than the Units / Minute limit between samples that are sampled at the Sample Rate the Rate of Change Limit the Tag is considered to be in a ROC alarm condition.

### Target Parameter

Each Tag has a Target Parameter that can be enabled to write a value back to an OPC Item. Because each Tag can have another Tag as a data source a Tag value can be transferred to unlimited numbers of OPC Items on both a local OAS Service or on other remote OAS Services.