BacnetEnumValue Function Block

The BacnetEnumValue exposes a raw object over BACnet as Multi-State Value BACnet object.

Figure 1: BacnetEnumValue Function Block

Figure 2: BacnetEnumValue Property Sheet

Inputs

Input Name

Description

In

It is a 32-Bit floating input point.

Fail Detect Enable

0: Disable

1: Enable

Set it to true to enable the fail detection feature.

Note: This feature enables the monitoring of periodic updates of a function block over a network.

Fail Detect Fallback Value Select

0: InvalidValue

1: LastknownGoodValue

2: FixedValue

InvalidValue: Out is set as NULL LastknownGoodValue: If the last Out value was not NULL, then Out is retained as it is; otherwise, a value from the Default Value parameter goes to Out.

FixedValue: Fail Detect Fixed Value goes to Out.

Fail Detect Fallback Value

Define the value that should be set to Out (when failure is detected), when Fail Detect Enable is True, and Fail Detect Fallback value is set to Fixed Value. It is a Enum value with a range of 1 to 16.

Fail Detect Delay

Update interval in seconds within which Present Value should get written over BACnet periodically. Present Value not written within this interval will result in failure, and Out will be set with the value as configured in Fail Detect Fallback Value Select. It is a 32-bit integer value with range 0 to 3600 sec.

Table 1: Inputs of BacnetEnumValue Function

Outputs

Output Name

Description

Out

When Out of Service is "false" - Out is same as In, if In is connected and its value is not NULL. When In is NULL, Out take value from Default Value parameter. This value will also be exposed as Present Value over BACnet. Out will change when Present Value is changed over BACnet or Default Value parameter is changed via Tool. When Out of Service is "true" - Out is decoupled from In. Out is the Present Value written over BACnet.

Status Flags

Displays the status of this function block. It can be 0 or the following value.

2 - Fault

8 - Out of Service

Example:

A value of 8 means the function block is in Out of Service state.

A value of 2 means the function block is in Fault state.

A value of 0 means the function block is not in Out of Service state.

Event State

Displays the present event state of this function block. It will always be in the following state:

0 - Normal

Out of Service

It shows whether the function block is in out of service state or not.

Out of Service is modifiable over BACnet. Setting Out Of Service to true, decouples In from Out, i.e. In values no longer show up on Out.

When Out of Service is true, Out can be overwritten over BACnet (via Present Value property).

Table 2: Outputs of BacnetEnumValue Function

Parameters

Parameter Name

Description

Number of States

Define the total number of discreet states starting from 1, that Out can have.

Default Value

Define the value that shows up on Out at controller startup, when In is not connected.

Bacnet Object Instance

It shows the instance number of this BACnet object function block.

State text

Facets define enumeration values and the associated texts for BACnet data points. The enumeration values can be defined in the range 1-16.

Fail Detect Fixed value

Define the value that should be set to Out (when failure is detected), if Fail Detect Enable is "true" and Fail Detect Fallback Value is set to "Fixed Value".

Out Save

Master Sync Enabled: If you set it to true, the last output will be set as output for one cycle after the controller restarts. The application can use it to return to the same state before the controller restart.

If the present value is changed via BACnet , then the same value will be set to present value after power cycle. If there is no value saved then first time it will use the default value.

OUT: To enable or disable the Out feature.

Fail Detect

Fail Detect only works if In is NULL and Fail Detect Enable is set to "true".

Fail Detect Time - Update interval in seconds within which Present Value should get written over BACnet periodically. Present Value not written within this interval will result in failure and Out will be set with the value as configured in Fallback Value.

Fail Detect Value: Select the Fail Detect Value type.

  • "InvalidValue" - Out is set as NULL
  • "LastknownGoodValue" - If last Out value was not NULL then Out is retained as it is, otherwise value from Default Value parameter goes to Out.
  • "FixedValue" - "Fail Detect Fixed Value" value goes to Out.

Enable - Set it to true to enable fail detection feature.

Note - This feature enables monitoring of periodic update of a function block over network.

Table 3: Parameters of BacnetEnumValue Function

Examples

Figure 3: Example - BacnetEnumValue Function Block and Property Sheet

Refer to General Description for general information about IRMN4 Function Blocks.