Troubleshooting - Metasys - LIT-12011288 - Software Application - Metasys Building Automation System - 6

DLLR Technical Bulletin

Product
Building Automation Systems > Building Automation Systems > Metasys Building Automation System
Document type
Technical Bulletin
Document number
LIT-12011288
Version
6
Revision date
2013-10-15

Use Table 1 to diagnose and solve potential DLLR problems.

Table 1. DLLR Troubleshooting Guide

Symptom

Cause

Solutions

A DLLR object indicates Trouble status.

Demand Limiting cannot shed enough loads to meet its target.

If no loads are available to be shed, the Current Demand Limit is too low to be met with the existing loads. Use a higher DL Tariff Target value or add more loads with a Demand Limiting shed strategy. You also can set the value of the demand limit target by writing to the Current Demand Limit attribute.

Load Rolling cannot shed enough loads to meet its target.

If no loads are available to be shed, the Current LR Target is too high to be met with the existing loads. Use a lower LR Tariff Target value or add more loads with a Load Rolling shed strategy. You also can set the value of the LR target by writing to the Current LR Target attribute.

No meter is defined and the DLLR shed strategy includes Demand Limiting.

Define a meter or change the DLLR object's shed strategy to Load Rolling only.

The demand meter is offline or unreliable.

Resolve the meter communication problem.

The EOI object is offline or unreliable.

Resolve the EOI object communication problem.

Loads are shedding too aggressively.

Meter count is too low.

Use a demand meter that provides at least 100 counts per minute or adjust the Error Limit value.

Meter migrated from the N1 network is being used.

Service time of the migrated NCM is not fast enough to provide for an updated value to the DLLR algorithm once per minute. Move the meter to a field controller connected to the NAE or NCE.

Configured load ratings for the equipment may not match actual load ratings.

Reconfigure load ratings using the assistance of personnel qualified to formulate accurate load ratings for the monitored equipment.

The Sensitivity attribute for the DLLR object is set to High.

Change the sensitivity setting to Medium or Low.

The load is too large.

A large load may be a result of aggregating multiple pieces of equipment into one load. This type of aggregation is not recommended because you lose granularity and cannot fully leverage the advantages offered by DLLR. If capacity permits, break the load into pieces. If you cannot create separate loads, use care when aggregating loads to keep each load small.A large load also may occur with a single piece of equipment. To avoid aggressive shedding, consider using alternative control strategies. See Chiller/Boiler Step Strategy for an example.

Loads are shedding too conservatively.

The Sensitivity attribute for the DLLR object is set to Low.

Change the sensitivity setting to Medium or High.

Configured load ratings for the equipment may not match actual load ratings.

Reconfigure load ratings using the assistance of personnel qualified to formulate accurate load ratings for the monitored equipment.

Loads are shedding, but energy use is not being reduced.

DLLR object is set to Monitor Only mode.

Change or command the DLLR object to Shed mode.

No loads are shedding.

DLLR may not need to shed any loads at this time.

Check the DLLR Status attribute. If it indicates Normal, no loads need to be shed at this time.

The particular load that is not being shed is disabled, locked, in comfort override, or released plus locked.

See Metasys System Help (LIT-1201793) for steps to take based on the current condition of the load.

There is a mismatch between the load shed strategy and the DLLR object shed strategy.

Edit the load so that the load shed strategy matches the DLLR object shed strategy. DLLR cannot shed a load for Demand Limiting if the load shed strategy is Load Rolling only, and cannot shed a load for Load Rolling if the load shed strategy is Demand Limiting only.