Electric Demand Monitoring Object - Metasys - LIT-1201793 - Software Application - Site Management Portal - 12.0.50

Metasys Site Management Portal Help

Brand
Metasys
Product name
Site Management Portal
Document type
User Guide
Document number
LIT-1201793
Version
12.0.50
Revision date
2023-06-02
Language
English

Menu Selection: Insert > Object > Electric Demand Monitoring

The Electric Demand Monitoring Object is a specialized object that monitors the power consumption in a fixed 30-minute window. This object uses an Accumulator or Analog Input and calculates the demand every minute. The object calculates a projected demand for the end of the 30-minute window, and compares that demand value to the target demand. If the projected demand value exceeds the target demand value, the object triggers an alarm notification. The default view of the object is a graph of the demand values.

Note: In the Notes column, letters indicate the following: A - Archive, C - Configurable, D - Default Attribute, F - PMI Refreshing R - Associate with Reliability, W - Writable.
Note: In the BACnet Notes column, letters indicate the following: O - BACnet optional property, P - BACnet proprietary property, Q- BACnet required property.
Table 1. Electric Demand Monitoring Object Attributes
Attribute Name Notes BACnet Notes Initial Value Values\Options\Range Description
Present Value D,F,R Q 1

1=Normal

2=Alarm Level 1

3=Alarm Level 2

For the Electric Demand Monitoring object, the Present Value displays the present demand alarm level. There are three states:

- Normal State (no alarm generated)

- Alarm level 1

- Alarm level 2

Contract Receiving Power W,C,A Q 0 0.0 kW to 99999.9 kW This attribute represents the electric power contracted from a power company as a value of electric energy of 60 minutes.
Alarm Value of Power W,C,A Q 0 0.0 kW to 99999.9 kW This attribute shows the alarm value of electric power as a value of electric energy of 60 minutes. If this value is exceeded, the Present Value becomes 3 and generates alarm level 2.
Target Value of Power W,C,A Q 0 0.0 kW to 99999.9 kW This attribute shows the electric power that can be supplied by a generator as a value of electric energy of 60 minutes. If this value is exceeded, the Present Value becomes 2 and generates demand alarm level 1.
Units W,C,A Q kW Default - kW This attribute represents the engineering unit of all real type properties that show electric energy.
JCI List of Pulse Counter Reference C,A O Null

Pulse Attributes reference PV of (AI, AV, or Accumulator)

This attribute indicates the references to electric power Pulse input devices. This reference can be either an Accumulator, an AV, or an N2 Pulse Counter object.
Time Synchro-nization Mode W,C,A P Internal Normal

1=External

2=Internal Normal (0 min, 30min)

3=Internal Custom (arbitrary)

This displays three modes:

External: If the external signal is Pulse type, the demand interval stops and starts whenever a Pulse is received. If the external signal is Analog, the demand interval stops and starts when the value changes (increments or decrements).

Internal Normal: When the time is XX:00:00 and XX:30:00, demand timing will stop and start.

Internal Custom: Demand interval begins after startup of an NAE, the addition of the object, or when a demand reset command is issued. The demand interval stops and starts 30 minutes from the starting time. For example, if it stops and starts at XX:12:03, then it will stop and start next at XX:42:03.

Time to Mask W,C,A P 5 0 min to 25 min This attribute indicates the time that is not treated as an alarm even if the measured value exceeds an Alarm Value of Power or Target Value of Power after starting the demand monitoring of a 30-minute-period.
EOI Object C,A P   If operating in External mode, refer to the AI, AV, or BI object to input the external interval signal. Only this property is configurable.
Input Mode W,C,A P Pulse

1=Pulse(PI)

2=Analog(AI or AV)

This attribute switches the reference input signal between Pulse signal such as PI, and Analog signal such as AI and AV. When input mode is Analog, any change of value is an EOI. In Pulse mode (typically BI), only transitions to True are EOI pulses.
JPN Rate Constant W,C,A P 50,000 0 to 50,000 The numeric value that is input onto a Pulse object is the electric energy. Set a constant to multiply.
Pulse Constant W,C,A P 100 0 to 50,000 The numeric value that is input onto a Pulse object is the electric energy. Set a constant to multiply.
Rollover Limit     0   This attribute specifies the highest counter value before the Pulse Counter rolls over to zero.
Reliability Time Interval   Q 1 0 min to 30 min For the Electric Demand Monitoring (EDM) object, power usage is calculated from the difference between one minute previous and the value of JCI List of Pulse Counter Reference.

If the difference in usage is zero, recognize it as an input error and set the status to unreliable. However, even when the object is normal, this property remains active, because the reliability check is masked if the power usage is low and the difference in usage is zero.

In addition, EDM is unreliable if the mask time is set with this property, because the difference in calculation is reset in a 30 minute period. If it is unreliable at the start of 30 minutes, EDM becomes unreliable. That is, it is unmasked at the start time, for example HH:00 or HH:30, and becomes unreliable.