DLLR Object Attributes - Metasys - LIT-12011964 - Software Application - System Configuration Tool - 16.0

SCT: System Configuration Tool Help

Brand
Metasys
Product name
System Configuration Tool
Document type
User Guide
Document number
LIT-12011964
Version
16.0
Revision date
2023-10-02
Language
English

The DLLR object is divided into three tabs, the Focus/Configuration Tab, the Profile Tab, and the Load Summary Tab. If you add extensions to this object, see Extensions for descriptions of the extension tabs.

Table 1. DLLR Object Attributes
Name / View Group

Attribute ID Configurable (C) Writable (W)

Attribute Description
Object Type -- Object

79

The Object Type attribute indicates the Object Type as displayed in the Metasys software and as exposed to a BACnet network.

Name -- Object

2390 C W

The Name attribute contains a freely definable user-friendly name for the object that is independent of the Item Reference or the location of the object in the physical network. The Name is used as the label in the All Items navigation tree. The Name is shown in alarm reports, the event and audit viewers, and in summaries. The Name does not need to be unique to the site.

The Name defaults to the object identifier you used during manual object creation but can be edited later.

Enabled -- Object

673 C W

The Enabled attribute provides a mechanism to stop DLLR operation. When disabled, DLLR releases all shed loads except those that are locked shed. Also, DLLR does not perform any calculations, report alarms, or issue any commands to any loads when disabled. DLLR attributes can be changed, but no actions are taken until DLLR is enabled.

When enabled, DLLR operation starts again. If Shed mode is active, the configured DLLR strategies begin shedding loads as needed. If Monitor Only mode is configured, simulated load shedding begins.

Authorization Category -- Object

908 C W

The Authorization Category classifies the object by the category of system or equipment that it monitors to aid in the determination of user access privileges and alarm routing.

Examples: Energy, HVAC, Fire, Security
Description -- Object

28 C W

The Description attribute contains a user-defined description of the object.
Shed Strategy -- Setup

4187 C W

The Shed Strategy attribute allows you to specify which shedding strategy the DLLR uses. The Shed Strategies include:
  • Demand Limiting and Load Rolling
  • Demand Limiting Only
  • Load Rolling Only (default)
Mode -- Setup

961 C W

The Mode attribute controls whether DLLR is actively shedding Loads (Shed mode) or is simulating Load shedding (Monitor Only mode). The mode pertains to both the Demand Limiting and Load Rolling strategies simultaneously. The Modes include:
  • Monitor Only - simulated shedding occurs, where loads appear shed but output points are not actually commanded or turned off.
  • Shed - true shedding occurs where output points are commanded.
Monitor Mode Release -- Setup

1016 C W

The Monitor Mode Release attribute allows you to specify the load output release behavior when DLLR is commanded to Monitor Only mode from Shed mode. If set to Release immediately, the outputs of loads that are not locked are immediately released regardless of whether their Minimum Shed Time has expired. If set to Release After Min Shed Time, the outputs of loads that are not locked are released only after their Minimum Shed Time expires. Possible behaviors include:
  • Release Immediately
  • Release After Min Shed Time
Meter Object -- Setup

2110 C W

The Meter Object identifies the Metasys object (for example, Pulse Meter, AI, AV) that is used for the energy rate if the Demand Limiting strategy is configured. If only the Load Rolling strategy is used, a meter is not required. The Meter Object should be defined on the same supervisory controller as the DLLR Object. Do not use an N1 Integration object for the meter unless you can guarantee that the NCM Service Time is always less than 60 seconds because the DLLR algorithm requires an updated meter value every minute.

Profile Tracking Period -- Setup

4191 C W

The Monitor Mode Release attribute allows you to specify the load output release behavior when DLLR is commanded to Monitor Only mode from Shed mode. If set to Release immediately, the outputs of loads that are not locked are immediately released regardless of whether their Minimum Shed Time has expired. If set to Release After Min Shed Time, the outputs of loads that are not locked are released only after their Minimum Shed Time expires. Possible behaviors include:
  • Release Immediately
  • Release After Min Shed Time
Table 1. Load Output Release Options
Profile Tracking Period Start Time End Time
Hourly At the top of the current hour.

Example: 08:00:00 A.M.

60 minutes from the current hour.

Example: 09:00:00 A.M.

Daily 12:00:00 A.M. current day 12:00:00 A.M. next day
Weekly 12:00:00 A.M. Monday of current week 12:00:00 A.M. Monday of the next week
Monthly 12:00:00 A.M. first day of current month 12:00:00 A.M. first day next month
Manual The moment when the Reset Profile command is issued. Always Not Specified
There are three exceptions to when the Start Times and End Times can vary from what is shown in Table 218. The Start Times and End Times differ when:
  • a Reset Profile command is issued to the DLLR object while in Shed or Monitor Only mode
  • a Reset Initialization Parameters command is issued to the DLLR object while in Monitor Only mode
  • the controller is downloaded or reset
Note: The Start Times and End Times are not reset when DLLR changes from Monitor Only mode to Shed mode. Also, when the DLLR object is disabled, the current profile is copied to the previous profile, the current profile values are all set to 0, and the times are all set to undefined.
DLLR Startup Behavior -- Setup

4282 C

The DLLR Startup Behavior attribute selects which mode the feature is set to whenever the supervisory controller is restarted or its database is downloaded. Two selections are offered:
  • Startup in Monitor Only mode - DLLR starts in Monitor Only mode, even if it had been commanded or configured to Shed mode before the restart or download. Also, if the DLLR object was disabled while in Shed mode, it reverts to Monitor Only mode when enabled.
  • Startup in last commanded mode - DLLR starts in the mode that was active at the time the controller was restarted or its database downloaded.
Regardless of the selection, the following also apply:
  • Any Comfort Override commands that were in place before the startup are persisted.
  • Any previous Shed commands are not automatically persisted to loads on startup. DLLR evaluates the current situation and completes all calculations before issuing any new Shed commands to loads.
  • When DLLR starts issuing Shed commands to loads, it resumes where it left off with the first eligible, lowest-priority load.
Stop DLLR audits in Monitor Only mode -- Setup

4500 C W

The Stop DLLR Audits in Monitor Only Mode attribute specifies whether an audit entry is created each time a load is shed or released when DLLR is in Monitor Only mode and the NAE’s Enabled Audit Level is set to 3 or 4. (When DLLR is in Active mode, an audit entry is always created to record that event.) The default is False, but if you set it to True, no audit entries are created in Monitor Only mode.

Demand Interval Length -- Demand Limiting

2112 C W

The Demand Interval Length attribute specifies the length in minutes of an interval for the Demand Limiting strategy. This value is normally obtained from the energy utility. The DLLR Interval Lengths set specifies the possible interval lengths (15, 30, or 60).

Algorithm

2114 C W

The Algorithm attribute specifies which algorithm is used for the Demand Limiting strategy (Fixed Window or Sliding Window). In most cases, the Sliding Window Algorithm is required by North American utilities, while the Fixed Window Algorithm is used by European utilities.

DL Tariff Targets -- Demand Limiting

4185 C W

The DL Tariff Targets attribute is the list of energy targets for the Demand Limiting strategy. Each target consists of a target value and an entry from the Target Description set identifying the type of target, such as On-Peak. If the Demand Limiting strategy is used, there must be at least one target defined. Only one target is active at any time. The Active DL Target attribute specifies which target is currently active. The Target Description set includes:
  • Continuous
  • Off-Peak
  • On-Peak
  • Semi-Peak
  • Shoulder
  • Summer Off-Peak
  • Summer On-Peak
  • Winter Off-Peak
  • Winter On-Peak
  • Summer Semi-Peak
  • Winter Semi-Peak
  • Summer Shoulder
  • Winter Shoulder
Active DL Target -- Demand Limiting

4208 C W

The Active DL Target specifies which of the defined Demand Limiting targets is currently active. When this attribute changes, the Active DL Target Changed attribute indicates True until the start of the next interval. This attribute uses the Target Description enumeration set.

LR Tariff Target -- Load Rolling

4186 C W

The LR Tariff Targets attribute lists the energy targets for the Load Rolling strategy. Each target consists of a target value and an entry from the Target Description set identifying the type of target, such as On-Peak. If the Load Rolling strategy is used, there must be at least one target defined. Only one target is active at a time. The Active LR Target attribute specifies which LR Target is currently active. The Target Description set includes:

  • Continuous
  • Off-Peak
  • On-Peak
  • Semi-Peak
  • Shoulder
  • Summer Off-Peak
  • Summer On-Peak
  • Winter Off-Peak
  • Winter On-Peak
  • Summer Semi-Peak
  • Winter Semi-Peak
  • Summer Shoulder
  • Winter Shoulder
Active LR Target -- Load Rolling

4209 C W

The Active LR Target attribute specifies which of the defined Load Rolling targets is currently active. When this attribute changes, the Active LR Target Changed attribute indicates True until the start of the next interval if demand limiting is configured, or the next minute if load rolling only is configured. This attribute uses the Target Description enumeration set.

EOI Attribute -- Fixed Window Alg

2115 C W

The EOI attribute is a reference to the Metasys object (for example, BI, BV) supplying the EOI pulse, which is used for the Fixed Window algorithm only. The EOI pulse is used to synchronize DLLR’s demand interval to the utility’s demand interval. If this is not specified, DLLR performs its own interval timing, which is not as accurate.

This EOI attribute can be any binary type object, as long as the following requirements are met:
  • A permanent communication path must exist between this attribute and the DLLR object; therefore, the EOI point and DLLR object should reside on the same supervisory controller.
  • The attribute must be a numerical attribute, in which a change from 0 to 1 indicates the end of interval and the beginning of the next interval. The EOI Status attribute is set to Off Normal when the object supplying the EOI pulse becomes offline or unreliable to the DLLR object.
Display Precision -- Display

661 C W

The Display Precision attribute defines the decimal display precision for all real values (floating values) in the DLLR object.

Rate Units -- Display

819 C W

The Rate Units attribute specifies the energy units used for instantaneous energy demand attributes and referenced in the DLLR Profile and Load Summary (for example, kW). If a meter is defined, the Rate Units attribute indicates the units of the meter.

Consumption Units -- Display

820 C W

The Consumption Units attribute specifies the consumption energy units (for example, kWh).
Unreliable Meter Shed Rate -- Advanced Demand Limiting

4190 C W

The Unreliable Meter Shed Rate attribute specifies how much load the DLLR object should keep shed if the meter goes unreliable, provided the Use Unreliable Meter Shed Rate option is selected for the Unreliable Meter Options attribute.

Unreliable Meter Options -- Advanced Demand Limiting

4189 C W

The Unreliable Meter Options attribute allows you to specify what should happen to Demand Limiting if the meter becomes unreliable or goes offline. These options are as follows:
  • Stop Shedding - no more shedding occurs until the meter is again reliable. Currently, shed loads continue to be shed until their Max Shed Time expires.
  • Maintain the Current Shed Rate - as loads are released, DLLR sheds other Loads to maintain the current amount of shed load.
  • Use Unreliable Meter Shed Rate - sheds or releases loads as needed to maintain the amount of load specified in the Unreliable Meter Shed Rate.

The second and third options cause Demand Limiting to act similarly to the Load Rolling strategy. If the Demand Limiting strategy is not defined, an offline or unreliable meter prompts no actions. Also, when the meter goes offline or unreliable, DLLR sets its Meter Status attribute to Off Normal and continuously updates its Minutes Since Meter Failure attribute (up to the interval length) until the meter is again reliable. The Minutes Since Meter Failure value is listed under the Operational Data section of the DLLR object - Advanced view.

Limit Elevation -- Fixed Window Alg Advanced

2117 C W

The Limit Elevation attribute indicates the amount (in percent) by which the demand limit is increased at the beginning of the next interval to obtain the starting value of the demand limit profile. A high value may result in increased shedding toward the end of an interval. Changing this interval affects the next interval, not the current interval. As shown in Figure 62, the demand limit profile specifies for each minute the maximum allowed average power during the whole interval. If too much energy is consumed during the first half of the interval, because the limit elevation allowed this consumption, then more loads are shed during the second half of the interval, even though the actual metered power is then below the demand limit profile. In other words, the net effect of limit elevation is to defer aggressive load shedding to the second half of the fixed demand interval.
Figure 1. Use of Limit Elevation on a Demand Limit Profile

Sensitivity -- Sliding Window Alg Advanced

2125 C W

The Sensitivity attribute specifies the level of aggression for shedding Loads when using the Sliding Window algorithm. A High sensitivity sheds more loads sooner than a Low sensitivity.
  • Low setting - allows you to start shedding loads later and shedding loads over a shorter period of time. This setting reduces the amount of equipment that is turned off; however, it increases the possibility of exceeding the target.
  • Medium setting - (default) allows you to start shedding slightly earlier than a low setting and later than a high setting. This setting turns off equipment earlier than with a low setting, but does not have to turn off as much equipment at once as with the high setting.
  • High setting - allows you to begin shedding sooner into the demand peak. This setting decreases the possibility of exceeding the target; however, it increases the amount of equipment that is turned off.
Target Ramp Down Enabled -- Sliding Window Alg Advanced

1660 C W

The Target Ramp Down Enabled attribute specifies whether a target reduction causes an incremental ramp down over the course of one interval, as opposed to an immediate target drop that could result in major immediate Load shedding.

Error Limit -- Sliding Window Alg Advanced

34 C W

The Error Limit attribute limits the Smoothed ABS Error to a percentage of the Active Demand Limit. It can be used to reduce the size of the safety margin to avoid unnecessary overshedding. This value should be changed with care, since it increases the possibility of exceeding the demand limit target. The default value is 10%.