# SRV\_NC\_SMALL ## `SRV_NC_SMALL` (FB) FUNCTION\_BLOCK SRV\_NC\_SMALL Influence on the current state of the property 'PresentValue' (output) Priority Condition Function Notes Highest property 'OutOfService' = TRUE 'PresentValue' can be written directly Forced override of the output 'PresentValue' Middle state of at least one priority The state of the highest priority (1 = highest, prioritization of requests for the state of PresentValue: of the array <> NULL 16 = lowest) of the array <> NULL determines the value of 'PresentValue' Lowest states of all priorities 1 - 16 of the array On transition into this priority the value of the determination of the state of 'PresentValue', if there are no valid entries in the array := NULL the property 'RelinquishDefault' is written once to the output 'PresentValue'. Notes: The state of a priority of the array can take the following states: NULL (= inactive), FALSE (OFF), TRUE (ON) The most recent access defines the state of PresentValue. ('Last wins') Each new state of 'PresentValue' is transmitted only once when the state changes, there is no continuous transmission (= pulse function). Priority 6 The state of priority 6 must not be used (= written), as it is used for pulse generation on state change of the property 'PresentValue'. Each rising edge on 'PresentValue' generates a pulse (state: TRUE) of length 'MinimumOnTime' ('MinimumOnTime' > 0 s) of priority 6. Each falling edge on 'PresentValue' generates a pulse (state: FALSE) of length 'MinimumOffTime' ('MinimumOffTime' > 0 s) of priority 6. Notification Class Conditions: 1. The property 'RecipientList' must be provided with the attribute 'WRITEABLE'. 2. The instance number must be identical to the Notification Class 3. The priorities (0 - 2) should contain values greater than 0 (e.g. all = 1) Persistence Conditions: 1. The desired property (e.g. 'Description') must be provided with the attribute 'PERSIST'. 2. Persistence remains until the value of the property changes (xEnValueChange = TRUE) and/or a rising edge is detected at the input 'xInit'. Unsolicited COV (= unsolicited transmission of state changes to all BACnet participants (broadcast)) Conditions: 1. The property 'SupportUnsolicitedCOV' must be set to 'TRUE' in the BACnet\_Server (central for all BACnet objects) InOut: | Scope | Name | Type | Initial | Comment | | ----------- | ------------------------------------- | ----------------------------------------- | -------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Input | `itfMasterConnector` | IMasterForServerObjectsPOU | | Input for the interface of the FB ‘MasterForServerObjectsPOU’ | | Input | `xInit` | `BOOL` | FALSE | Reassignment of all properties (write values/states and update outputs) (on every rising edge) | | Input | `udiObjectInstance` | `UDINT` | 40 | Object instance of the server object to be created | | Input | `sObjectNamePrefix` | `STRING(254)` | ‘’ | Optional prefix for forming the object name — CONCAT(sObjectNamePrefix,sObjectNameText) | | Input | `sDescriptionPrefix` | `STRING(254)` | ‘’ | Optional prefix for forming the description — CONCAT(sDescriptionPrefix,sDescriptionText) | | Output | `eObjectTypeFb` | `BACnet.CmpBACnet.IEC_BACNET_OBJECT_TYPE` | | Type of the object — feedback | | Output | `udiObjectInstanceFb` | `UDINT` | | Object instance of the server object to be created — feedback | | Output | `stProperties` | SRV\_NC\_SMALL\_PROPERTY\_OUTPUTS | | Structure with the current states of selected properties | | Output | `xRegistered` | `BOOL` | FALSE | Indicates successful registration of the server object | | Input Const | `eAccessRightAckReqEnable_IN` | `BACnet.CmpBACnet.IEC_BACNET_ACCESS` | BACnet.CmpBACnet.IEC\_BACNET\_ACCESS.BACNET\_ACCESS\_HIDDEN |

Specification of the access right for acknowledging
transitions by a client

| | Input Const | `eAccessRightRecipientList_IN` | `BACnet.CmpBACnet.IEC_BACNET_ACCESS` | BACnet.CmpBACnet.IEC\_BACNET\_ACCESS.BACNET\_ACCESS\_READ\_ONLY |

Specification of the access right for the list of
recipients by a client

| | Input Const | `eAccessRightEventDetectionEnable_IN` | `BACnet.CmpBACnet.IEC_BACNET_ACCESS` | BACnet.CmpBACnet.IEC\_BACNET\_ACCESS.BACNET\_ACCESS\_HIDDEN | Definition of the access right for the property 'Event Detection Enable' by a client | | Input Const | `eAccessRightEventEnable_IN` | `BACnet.CmpBACnet.IEC_BACNET_ACCESS` | BACnet.CmpBACnet.IEC\_BACNET\_ACCESS.BACNET\_ACCESS\_HIDDEN | Definition of the access right for the property 'Event Enable' by a client | | Input Const | `eAccessRightNotifyType_IN` | `BACnet.CmpBACnet.IEC_BACNET_ACCESS` | BACnet.CmpBACnet.IEC\_BACNET\_ACCESS.BACNET\_ACCESS\_HIDDEN | Definition of the access right for the Notification Type by a client | | Input Const | `eAccessRightNotificationClass_IN` | `BACnet.CmpBACnet.IEC_BACNET_ACCESS` | BACnet.CmpBACnet.IEC\_BACNET\_ACCESS.BACNET\_ACCESS\_HIDDEN | Definition of the access right for the Notification Class by a client | | Input Const | `xAckReqNormalEnable_IN` | `BOOL` | FALSE |

Enable/disable acknowledging of transitions to the
‘Normal’ state ( TRUE = enabled )

| | Input Const | `xAckReqFaultEnable_IN` | `BOOL` | FALSE |

Enable/disable acknowledging of transitions to the
‘Fault’ state ( TRUE = enabled )

| | Input Const | `xAckReqOffNormalEnable_IN` | `BOOL` | FALSE |

Enable/disable acknowledging of transitions to the
‘Off-Normal’ state ( TRUE = enabled )

| | Input Const | `eTriggeringUpdateActual` | ServerObjects\_TriggeringUpdateActual | ServerObjects\_TriggeringUpdateActual.CENTRAL\_TRIGGERING |

Definition of the trigger for cyclical updating of the outputs
NO\_TRIGGERING: no cyclical update
LOCAL\_TRIGGERING: cyclical update (time duration: tTimeUpdateActual)
CENTRAL\_TRIGGERING: cyclical update (time duration dependent on the number of server objects)

| | Input Const | `tTimeUpdateActual` | `TIME` | TIME#3s0ms | Update interval for updating the outputs | | Input Const | `eReliability_IN` | `BACnet.CmpBACnet.IEC_BACNET_RELIABILITY` | BACnet.CmpBACnet.IEC\_BACNET\_RELIABILITY.RELIABILITY\_NO\_FAULT\_DETECTED | Definition of the current state of the property ‘Reliability’ | | Input Const | `udiPriorityNormal_IN` | `UDINT` | 90 |

Specification of the priority for the jump to ‘Normal’ status ( S
) ( 0 - 255, 0 = highest )

| | Input Const | `udiPriorityFault_IN` | `UDINT` | 90 |

Specification of the priority for the jump to ‘Fault’ status ( S
) ( 0 - 255, 0 = highest )

| | Input Const | `udiPriorityOffNormal_IN` | `UDINT` | 90 |

Specification of the priority for the jump to ‘OffNormal’
( 0 - 255, 0 = highest ) ( S )

| | Input Const | `xEventDetectionEnable_IN` | `BOOL` | FALSE | General enable/disable of event detection (TRUE = enable) | | Input Const | `xEventNormalEnable_IN` | `BOOL` | FALSE | Enable/disable detection of transitions to the state 'Normal' (TRUE = enable) | | Input Const | `xEventFaultEnable_IN` | `BOOL` | FALSE | Enable/disable detection of transitions to the state 'Fault' (TRUE = enable) | | Input Const | `xEventOffNormalEnable_IN` | `BOOL` | FALSE | Enable/disable detection of transitions to the state 'Off-Normal' (TRUE = enable) | | Input Const | `eNotifyType_IN` | `BACnet.CmpBACnet.IEC_BACNET_NOTIFY_TYPE` | BACnet.CmpBACnet.IEC\_BACNET\_NOTIFY\_TYPE.NOTIFY\_TYPE\_ALARM | Specification of the type of the Notification object | | Input Const | `sDescriptionText` | `STRING(254)` | ‘’ | Text part of the description | | Input Const | `sObjectNameText` | `STRING(254)` | ‘’ | Text part of the object name of the server object to be created | | Input Const | `udiNotificationClass_IN` | `UDINT` | 0 |

Number of the Notification Class to which this Notification-
Class can pass messages

| | Input Const | `xEn` | `BOOL` | TRUE | Enable / disable communication ( TRUE = enabled ) | --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://support.powerio.com/hub/codesys-hvac/en/hvac-bacnet2-library/funktionsbausteine/server-objekte/srv_nc_small.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.