A set of digital and analog tags can be defined that are used to trigger callouts and report register values to the host. Any of the internal registers can be referenced for this purpose.
There can be 16 digital inputs (status), 8 digital outputs (coils), 16 analog inputs (inputs) and 8 analog outputs (holdings). The tags table has 8 rows. The tags table summarizes all the tags. There is a set of buttons used to create, read, update, delete, and re-order the tags.
The table displays 8 rows at once out of a total of 48 rows. The scroll bars are used to navigate the table.
| Tag Name | Descriptive name. |
| Type | The type of register: status, coil, holding, or input. |
| Src Reg | Source register number of an internal register. |
| Dst Reg | Destination register number of an internal register. |
| Value | Value of the tag at the time the Get button was clicked. |
| Units | Unit of measure for analog tags and state name for digital tags. |
| Alarm | State of the alarm condition at the time the Get button was clicked. ALARM, OK, or BYPASS. ALARM means the alarm condition has been met. OK means the alarm condition has not been met. BYPASS means the alarm has not been enabled using the Enable check box. If the Alarm check box is not checked then this field is blank. |
Each row begins with a check box that is used to select a row. The Up, Down, Add Digital, Add Analog, Modify, and Delete buttons are used to operate on the selected row. The Up and Down buttons move the selected row. The Add buttons append or insert new tags. The Modify button updates an existing tag. The Delete button removes a tag. The Get button refreshes the Value and Alarm fields by retrieving tag values from the terminal for all the tags in the table.
The source and destination register numbers refer to the register numbers before and after any defined transformation. For digitals these are the same. For analog the source is the raw register value and the destination is the transformed floating point value.
Status and coils can be appended, inserted, and modified. Each tag is configured using a pop-up dialog.
| Tag Name | 1 to 16 character descriptive name. If not present the tag is not used. |
| Type | Coil or status. |
| Register | Register number of an internal register. |
| 0 State Name | 1 to 4 character name of the 0 state. |
| 1 State Name | 1 to 4 character name of the 1 state. |
| Enable | Checked if this tag is to be used to trigger an event. |
| Value | An event is triggered when register transitions to this value. |
| Delay | Amount of time state must be retained for the event to occur. Seconds. |
| Alarm | The detected event is an alarm. |
| Sup | Suppress event. If checked no callout will be generated due to this event condition. |
When an event is generated all the tag values, whether checked or not, and the tag parameters are returned to the host. If the Alarm is set for a tag and that tag is in the alarm condition then the callout is an alarm.
Inputs and holdings can be appended, inserted, and modified. Each tag is configured using a pop-up dialog.
| Tag Name | 1 to 16 character descriptive name. If not present the tag is not used. |
| Type | Input or holding. |
| Register | Register number of an internal register. If the register has 32 bits then the register number must be an even number. |
| Units | 1 to 6 character name of the units of measure for the tag (i.e. kPa). |
| Digits | Number of digits to the right of the decimal place displayed in the Tags form. |
| Format | Format of the internal register (i.e. the bit layout). See table in next section for details. |
| Scaling | Type of scaling to be applied: none, linear, inferred, or fixed. If scaling is set to None then the Lo and Hi values are used directly to generate an event. Also the returned value is a raw value. If scaling is set to Inferred then an implied decimal point is assumed for the raw values. The Decimal parameter indicates the number of digits after the decimal point. For example, if Decimal is 1 and the raw analog value is 102, then 10.2 is the transformed value. If scaling is set to Linear or Fixed then a linear transformation is applied to the raw values. If Linear then the raw input range must be specified in Lo Raw and Hi Raw. If Fixed then then Lo Raw is set to 0 and Hi Raw is set to 32767 automatically. |
| Decimal | Number of decimal placed if inferred scaling is used. |
| Lo Raw | Low value of raw range if linear or fixed scaling is used. |
| Hi Raw | High value of raw range if linear or fixed scaling is used. |
| Lo Eng | Low value of scaled range if linear or fixed scaling is used. |
| Hi Eng | High value of scaled range if linear or fixed scaling is used. |
| Enable | Enable event detection and set type or disable event detection. There are three choices: Off, Range, and Change. If Off the tag is not used to trigger an event. If Range then a tag value out of range, less than Lo or greater than hi, will trigger an event. If Change then any change in the tag value will cause an event to occur. If the tag value is 0 then it is a non-event condition and non-zero means it is an event condition. |
| Lo | Event is triggered when register value is less than this. |
| Hi | Event is triggered when register value is greater than this. |
| Delay | Amount of time the tag value must be at this value before an event is triggered. In seconds. |
| Alarm | The detected event is an alarm. |
| Sup | Suppress event If checked no callout will be generated due to this event condition. |
When an event is detected all the tag values, whether checked or not, and the tag parameters are returned to the host. If the Alarm is set for a tag and that tag is in the alarm condition then the callout is an alarm.
The Lo and Hi values used to generate the event always refer to the transformed values and not the raw values unless Scaling is set to None. If scaling is set to None then the Lo and Hi values are used directly to generate an event. Also the returned value is a raw value.
The format of an internal register can be one of:
| 16U | 16 bit unsigned |
| 16S | 16 bit signed |
| 32Um | 32 bit unsigned, big endian (Modicon) |
| 32Ui | 32 bit unsigned, little endian (Intel) |
| 32Sm | 32 bit signed, big endian (Modicon) |
| 32Si | 32 bit signed, little endian (Intel) |
| 16X2FPm | two 16 bit registers, floating point, big endian (Modicon) |
| 16X2FPi | two 16 bit registers, floating point, little endian (Intel) |
| 32FPm | 32 bit floating point, big endian (Modicon) |
| 32FPi | 32 bit floating point, little endian (Intel) |