N2 Analog Input/ BACnet Analog Input

Transcription

1 Object Dictionary 1 N2 Analog Input/ BACnet Analog Input Introduction Note: The Johnson Controls N2 Analog Input object is considered a BACnet Analog Input object because it supports BACnet functionality. In addition, this object has Johnson Controls proprietary attributes. The N2 Analog Input object s attributes represent the external, visible characteristics of an analog input. This object integrates N2 controllers into supervisory controllers, resulting in: a consistent interface to N2 point objects for all controller types, so they appear as a homogenous set to the user interface flexibility in point mapping support for all Metasys and Facilitator controllers. Refer to Table 1 in the Controller chapter (LIT ) of the Object Dictionary. For example, this object allows you to map a temperature or humidity sensor point into a supervisory controller. See the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE) Standard for information on this object and the BACnet communication standard. May 1, 2002 Johnson Controls, Inc. Code No. LIT Software Release 5.1

2 2 N2 Analog Input/BACnet Analog Input Attributes Specific Attributes Table 1: Attribute Properties Table 1 lists the attributes specific to the N2 Analog Input object. The N2 Analog Input object also has the attributes of the Metasys Common object. Refer to Table 1 in the Metasys Common Object chapter (LIT ) for details. Attribute Name Data Type N30 M-Series N30 Default Value Options/Range Metasys Common Attributes See Table 1 in the Metasys Common Object chapter (LIT ). BACnet Required Attributes Event State Enumeration Normal Normal, Fault, Offnormal, High-Limit, Low-Limit Object Identifier BACnet Object ID C Out of Service Boolean False False True Present Value Float DNRW DNRW Status Flags Bit String False, False, False, False In Alarm, Fault, Overridden, Out of Service See BAC Status Flags Units Enumeration CW W Deg F See Units Enumeration Set in BACnet Optional Attributes Acked Bit String True, True, Transitions 1 True To-Offnormal, To-Fault, To-Normal See BAC Event Bits COV Float CW W 0.1 Deg F Any value > 0 Increment 2 Deadband 1 Float CW W 0.0 Device Type String CW W Null Limit: 20 characters * C - Configurable, D - Default Attribute, N - Value Not Required, R - Association to Reliability, W - Writable 1 These attributes are required if the object supports intrinsic reporting. 2 This attribute is required if the object supports Change-of-Value (COV) reporting.

3 Object Dictionary 3 Attribute Name (Cont.) Data Type N30 M-Series N30 Default Value Options/Range BACnet Optional Attributes (Cont.) Event Enable 1 Bit String CW W True, True, True To-Offnormal, To-Fault, To-Normal See BAC Event Bits Event Time Stamps 1 Array NONE_FFFF BACnetArray[3] of BACnet Time Stamp High Limit 1 Float CW W 70.0 Limit Enable 1 Bit String CW W False, False Low Limit Enable, High Limit Enable See BAC Limit Enable Low Limit 1 Float CW W 65.0 Max Pres Value Float CW W Min Pres Value Float CW W Notification Class 1 Unsigned Long CW W The BACnet Object Identifier of the Notification Class object used for routing Notify Type 1 Enumeration CW W Alarm Alarm, Event See BAC Notify Type Profile Name This BACnet optional attribute is not supported. Reliability Enumeration W W Reliable No Fault Detected (Reliable), No Sensor, Over Range, Under Range, Open Loop, Shorted Loop, Unreliable Other See Reliability Enumeration Set in Resolution Float W 0.1 Time Delay 1 Unsigned Short Update Interval Unsigned Short * C - Configurable, W - Writable CW W 0 Units = seconds 1 These attributes are required if the object supports intrinsic reporting. W 100 Units = hundredths of a second

4 4 N2 Analog Input/BACnet Analog Input Attribute Name (Cont.) Data Type N30 M-Series N30 Default Value Options/Range Display Precision Intrinsic Alarming Net N2 Address Net Point Address Johnson Controls Proprietary Attributes Enumeration CW W 10ths See Display Precision Boolean C False True, False Byte C 0 Range: Unsigned Short C 0 Range: Net Point Type Enumeration C 0 See Network Point Type Offline Boolean False False True Overridden Boolean R R False False True * C - Configurable, R - Association to Reliability, W - Writable

5 Object Dictionary 5 Attribute Definitions Table 2: Attribute Definitions Attribute Name Metasys Common Attributes Event State Object Identifier Out of Service Present Value Status Flags Units Acked Transitions Table 2 lists the definitions of the attributes specific to the N2 Analog Input object. Definition See Table 2 in the Metasys Common Object chapter (LIT ). BACnet Required Attributes Indicates if an active event state is associated with the object. If the object supports intrinsic reporting, this attribute indicates the event state of the object. If not, the attribute is Normal. Identifies the object with a unique numeric code. Indicates the offline/online state of the connected hardware. The attribute exists for compatibility with BACnet protocol and indicates whether the physical input that the object represents is in service. When out of service, the Present Value is not taken from the hardware input. Indicates the current value of the analog input. When Out of Service is True, this attribute is writable. Represents four Boolean flags that indicate the general health of an analog input. Three flags are associated with the values of other attributes of the object. The four flags are: In Alarm - In Alarm flag is False (0) if the Event State property value is Normal; otherwise, the In Alarm flag is True (1). Fault - Fault flag is True (1) if the Reliability attribute is not reliable; otherwise, the Fault flag is False (0). Overridden - Overridden flag is Logical 1 if the Present Value is decoupled from the hardware output, because operator intervention provided a different value. Out of Service - Out of Service flag is True if the Out of Service attribute value is True; otherwise, the Out of Service flag is False. Indicates the increments of measure used by the object. BACnet Optional Attributes Conveys three flags that separately indicate the receipt of acknowledgements for To-Offnormal, To-Fault, and To-Normal events. In Analog Input objects, transitions to High Limit and Low Limit Event States are considered Offnormal events. These flags clear with the occurrence of the corresponding event and set under any of the following conditions: upon receipt of the corresponding acknowledgement upon the occurrence of the event if the corresponding flag is not set in the Event Enable attribute (Event notifications are not generated for this condition. No acknowledgement is expected.) upon the occurrence of the event if the corresponding flag is set in the Event Enable attribute and the corresponding flag in the Ack Required attribute of the Notification Class object implicitly referenced by the Notification Class attribute of this object is not set (No acknowledgement is expected.) This attribute is required if the object supports intrinsic reporting.

6 6 N2 Analog Input/BACnet Analog Input Attribute Name (Cont.) COV Increment Deadband Device Type Event Enable Event Time Stamps High Limit Definition BACnet Optional Attributes (Cont.) Specifies the minimum change in Present Value that sends a COV Notification to subscriber COV clients. This attribute is required if the object supports COV reporting. Specifies a range between the High and Low Limits in which the Present Value must remain for a To-Normal event to generate under these conditions: The Present Value falls below the High Limit minus Deadband. The Present Value exceeds the Low Limit plus the Deadband. The Present Value remains within this range for a minimum period of time (specified in the Time Delay attribute). Either the High Limit Enable or Low Limit Enable flag is set in the Limit Enable attribute. The To-Normal flag is set in the Event Enable attribute. This attribute is required when the object supports intrinsic reporting. Contains the text description of the physical device connected to the Analog Input, usually describing the type of sensor. Conveys three flags for enabling and disabling To-Offnormal, To-Fault, and To-Normal events. In Analog Input objects, transitions to High Limit and Low Limit Event States are considered Offnormal events. An unreliable condition generates a Fault event. This attribute is required if the object supports intrinsic reporting. Conveys the times of the last To-Offnormal, To-Fault, and To-Normal event notifications, respectively. Time or Date time stamps have FF in each octet. Sequence time stamps are 0 if no event notification of that type has been generated. If intrinsic reporting is supported by the object, this attribute is required. Specifies a limit that the Present Value attribute must exceed before an event is generated. This attribute is required if the object supports intrinsic reporting. A To-Offnormal event generates under these conditions: The Present Value exceeds the High Limit for a minimum period of time, specified in the Time Delay attribute. The High Limit Enable flag is set in the Limit Enable attribute. The To-Offnormal flag is set in the Event Enable attribute. Once the Present Value exceeds the High Limit, the Present Value must fall below the High Limit minus the Deadband before a To-Normal event generates under these conditions: The Present Value falls below the High Limit minus the Deadband for a minimum period of time, specified in the Time Delay attribute. The High Limit Enable flag is set in the Limit Enable attribute. The To-Normal flag is set in the Event Enable attribute. Limit Enable Conveys two flags that separately enable and disable reporting of High Limit and Low Limit Offnormal events and their return to Normal. This attribute is required if the object supports intrinsic reporting.

7 Object Dictionary 7 Attribute Name (Cont.) Low Limit Max Pres Value Min Pres Value Notification Class Notify Type Reliability Resolution Time Delay Definition BACnet Optional Attributes (Cont.) Specifies a limit below which the Present Value attribute must fall before an event generates. This attribute is required if the object supports intrinsic reporting. A To-Offnormal event generates under these conditions: The Present Value falls below the Low Limit for a minimum period of time, specified in the Time Delay attribute. The Low Limit Enable flag is set in the Limit Enable attribute. The To-Offnormal flag is set in the Event Enable attribute. Once the Present Value falls below the Low Limit, the Present Value must exceed the Low Limit plus the Deadband before generating a To-Normal event under these conditions: The Present Value exceeds the Low Limit plus the Deadband for a minimum period of time, specified in the Time Delay attribute. The Low Limit Enable flag is set in the Limit Enable attribute. The To-Normal flag is set in the Event Enable attribute. Indicates the highest number (in engineering units) that is reliably obtained for Present Value. Indicates the lowest number (in engineering units) that is reliably obtained for Present Value. Specifies the notification class used when handling and generating event notifications for the object. This attribute implicitly refers to the BACnet Notification Class object that has a Notification Class attribute of the same value. This attribute is required if the object supports intrinsic reporting. Conveys whether the notifications generated by the object are Events or Alarms. This attribute is required if the object supports intrinsic reporting. Indicates whether the Present Value is unreliable and why. Sets the Reliability attribute to one of the following values when the Present Value attribute is written: Reliable - Last value written to Present Value was between the Min Value and Max Value limits. Unreliable High - Last value written to Present Value was greater than the Max Value limit. Unreliable Low - Last value written to Present Value was less than the Min Value limit. In addition to the three values to which the object can set the Reliability attribute, any value defined in the Metasys Common Object (LIT ) can be written directly to this attribute. Any value written to the Reliability attribute remains until the next time the Present Value is written. Indicates the smallest possible measurable change in Present Value (in engineering units). Specifies the minimum number of seconds that the Present Value must remain: outside the range defined by the High Limit and Low Limit attributes before a To-Offnormal event generates within the range defined by the High Limit and Low Limit attributes, including the Deadband attribute, before a To-Normal event generates This attribute is required for intrinsic alarming. Update Interval Indicates the time span (in hundredths of a second) between updates to Present Value when the input is not overridden or out of service.

8 8 N2 Analog Input/BACnet Analog Input Attribute Name (Cont.) Display Precision Intrinsic Alarming Definition Johnson Controls Proprietary Attributes Indicates the rounded position and decimal places to display for this object. Enables the definition of the intrinsic alarm related attributes. Net N2 Address Indicates the controller N2 Address (1-254) as defined by switch settings on the controller. Net Point Address Indicates the network point address of the specified type (1-256). Net Point Type Offline Overridden Indicates the point type in the controller. Indicates whether the object is online or offline as determined by the controller s offline condition. Shows the override state of the hardware (if supported by the hardware). Commands The N2 Analog Input object supports the commands listed in Table 3. The order of the commands in the table reflects how the commands appear on the user interface. Table 3: Supported Commands Command Name Parameters Access Level Description Override The value to be written to the Supervise Updates the Present Value at Command Priority equal to Operator Override. Present Value attribute. Override Release Supervise Releases Command Priority Operator Override from Present Value. Enable Modify Allows distribution of Changes-of-Value and commanding. Disable Modify Prevents distribution of Changes-of-Value and commanding. Controls Group 507 E. Michigan Street P.O. Box 423 Milwaukee, WI Printed in U.S.A.