### BACnet Analog Value Parameter The information below provides a FULL description of this microblock and all of its properties. What information you see and what you can do with it depends on your license and the application you are in, and in some cases, a controller's driver version.
Microblock family | Sys In microblocks
Icon and symbol |
What it does | This microblock specifies a numeric value to be sent to another microblock in the control program. Any BACnet device on the network can read or change the value of this parameter. If no BACnet device changes the value of this parameter, the default value is used. The value appears to other BACnet devices as the Present Value property of a BACnet Analog Value Object. You can configure this microblock to make its value available on the Rnet.
Click for details below Properties Alarms Rnet Tips and tricks
#### Properties TIPS Alt+click any value in the WebCTRL® or Field Assistant interface to view property details, including its editing privilege and expression (location path) for use on graphics. You can right-click some properties in the EIKON® Property Editor and select Make editable or Make read-only to determine that property's functionality in your system.
Display Name | The microblock label used in the EIKON® application and the WebCTRL® interface. You can use any characters except the " character.
Reference Name RefName | Use the default reference name unless you want a more descriptive name for graphics or network links. Limitations: lower case only limited to 40 characters cannot begin with a number must be unique within a control program
Description | (optional) A BACnet-visible microblock description.
Lock Present Value | Check to output the locked value from the microblock instead of the microblock's calculated value.
Editing Privilege | Preset - Each microblock property has an appropriate privilege or role assigned to it. You can use Global Modify in the WebCTRL® interface to find out what the actual privilege is. CAUTION If you change the Editing Privilege from Preset, the privilege you select will be used for all properties of this microblock, which is not always desirable.
Default Value | The value the control program uses until a user changes the value in the system interface.
Units | The unit of measurement of the microblock's present value. Select from the BACnet engineering units in this droplist. For some microblocks, you can customize the droplist by selecting Options > Preferences > Droplist Options.
Property Page Text
Show Property Page Text | Check to show this microblock's value on the equipment's Properties page.
Property Page Text | You can edit the microblock description that appears on the Properties page. See "Editing Properties page text using special characters" and "Formatting a microblock property" in EIKON® Help.
BACnet Configuration
Network Visible | Check to allow other BACnet equipment to read or change the microblock's present value. Must be checked for this microblock to generate alarms.
Critical Value | If your control program has logic that writes a critical value to this microblock periodically, select this option to have the system attempt to upload this microblock’s value (Relinquish Default property) and preserve it through a download, controller restart, or power loss.
Object Instance | Auto-assign - A BACnet Object ID is assigned by the system. Use specific value - (0–3999999) Assign a number that is unique within the controller.
COV Increment | An Analog Network Input (ANI) that references this microblock in its Address field tries to subscribe to this microblock's COV (Change of Value) service. If subscription succeeds, the ANI receives a value from this microblock only when this microblock's present value changes by at least the COV Increment. If subscription fails, the ANI reads this microblock's value at intervals specified in the ANI's Refresh Time field.
#### Alarms
Potential alarm source | Check to make this microblock available in the system's Alarm Sources list.
Critical | Determines the color of the system-wide alarm button when the alarm comes in if the alarm's Template field is set to Universal. = Critical = Non-critical
Category | The category you want to use to filter this microblock's alarms on the system's Alarms page > View tab.
Template | Universal - Allows your system to use the Alarm text and Return text defined in the microblock, and the Critical checkbox to determine the color of the system-wide alarm button when the alarm comes in.
Alarm
Low Limit Enable | Check to send an alarm when the microblock's present value remains below the Low Limit value for the defined Delay Seconds.
Low Limit | The value the microblock's present value must drop below to send an alarm.
High Limit Enable | Check to send an alarm when the microblock's present value remains above the High Limit for the defined Delay Seconds.
High Limit | The value the microblock's present value must rise above to send an alarm.
Dead Band | The amount inside the normal range by which an alarm condition must return before a return-to-normal notification is generated. EXAMPLE
Delay Seconds | The time the microblock's present value must remain in an alarm condition before the microblock sends an alarm.
Alarm text | The message displayed on the WebCTRL® Alarms page > View tab when an alarm condition occurs. A relative path is useful for alarm messages that you will reuse in multiple WebCTRL® locations because the path is relative to the item that contains the path.
Alarm requires acknowledge | Check to require that an operator acknowledge alarm notifications on the system's Alarms page > View tab.
Return to Normal
Return Enabled | Check to send a message when an alarm condition has returned to normal.
Return text | The message displayed on the WebCTRL® Alarms page > View tab when an alarm condition returns to normal. A relative path is useful for alarm messages that you will reuse in multiple WebCTRL® locations because the path is relative to the item that contains the path.
Return requires acknowledge | Check to require that an operator acknowledge return-to-normal notifications on the system's Alarms page > View tab.
Fault
Fault Enabled | Check to send a message when a fault condition occurs, such as a misconfigured or non-existent sensor.
#### Rnet NOTE A control program that uses these Rnet features works only with v5.5 or later systems and v5.5 or later drivers.
Enable Rnet | Check to allow this microblock to communicate its value(s) to and from a sensor.
Rnet Tag | All values from a ZS or wireless sensor must have an Rnet tag that defines what type of information this microblock's value represents. For a ZS sensor, it also determines how the sensor will display the value. For example, if you select Static Pressure Setpoint (411), the sensor displays the setpoint, a target icon to indicate it is a setpoint, and the number 411 in the lower left corner to identify the value is a static pressure setpoint. NOTE If the Rnet tag droplist does not have the tag you want, you can create a custom tag in the EIKON® application.
Display Resolution | Defines the resolution of the value to be displayed on the ZS sensor. For example, 1 displays only integers (example: 74) and 0.5 displays values to the nearest 0.5 (example: 74.5).
Editable | Select to make this microblock's value editable on the ZS sensor.
Edit Increment | Select how much you want each press of the sensor's or button to change the microblock's value.
Minimum | Enter the lowest amount that this value can be changed to on the ZS sensor or in the WebCTRL® interface.
Maximum | Enter the highest amount that this value can be changed to on the ZS sensor or in the WebCTRL® interface.
ZS Sensor Display Configuration |
Show on: | Check the sensor screen(s) that you want this microblock's value displayed on. Home Screen (1): When more than one value is assigned to the Home screen, the values cycle from one to the next. Typically, the first item displays for 10 seconds and any other items display for 3 seconds each. Information Screen (2): This screen is accessed by pressing the sensor's button. Diagnostics Screen (3): This screen is accessed by holding the sensor's button for at least 3 seconds. NOTE Select Reorder > Sensor Display Order in EIKON® to define the order in which multiple microblock values will appear on each sensor screen.
#### Tips and tricks Preserving Critical Values If you use an Analog Network Output microblock to periodically write a critical value from within a control program to this microblock’s Relinquish Default property, and you check the Critical Value field, the system will attempt to upload this microblock’s value and preserve it through a download. In the following example, the High Peak Recorder records the highest supply temperature each day. The Peak Value BACnet Analog Value Parameter has a reference name of peak_value, an object instance of 4013, and Critical Value is checked. The Peak Value ANO2 microblock’s target address is bacnet://this/AV:4013/104. Thus, the ANO microblock periodically (once per minute, or based on COV) writes the day’s peak supply temperature to the BAV Parameter’s Relinquish Default property (104). In the event of a download, the system uploads the Relinquish Default property from the BAV Parameter microblock, downloads to the controller, then writes the stored Relinquish Default property to the microblock with refname peak_value. So even if the program is edited and reloaded, the value in the BAV parameter is preserved, provided the BAV’s refname does not change. When the controller restarts, the Reset on start-up logic feeds the peak value back into the peak recorder and disables the ANO2, preserving the peak value in the High Peak recorder through the download and preventing the ANO2 from overwriting the previous peak until the value has been restored.