Accumulator Object - Metasys - LIT-12011964 - MS-SCTRMOT-0 - MS-SCTSWO-0 - MS-SCTSWO-6 - Bulb controller - Metasys System Configuration Tool - 13.2

Metasys SCT: System Configuration Tool Help
Product
Building Automation Systems > Building Automation Systems > Metasys System Configuration Tool
Document type
User Guide
Document number
LIT-12011964
Version
13.2
Revision date
21/01/2020

Menu Selection: Insert > Object > Accumulator

The accumulator object allows you to count pulses, which are often provided by energy meters. The accumulator objects can feed their Present Values to the Pulse Meter Object.

Note: The Accumulator’s Interface Value updates when the hardware is read by the Pulse Meter Object or when the hardware’s current value changes.

The following table describes the types of accumulator objects and how to add them to the Metasys system. The Integration (Device) Type column indicates the type of integration and device in which the accumulator object resides.

Table 1. Accumulator Types

Integration (Device) Type

Description

Steps and Tips

IP BACnet Integration

(BACnet Device)

Provides integration of BACnet controllers with supervisory controllers through a BACnet accumulator mapper. This object provides information on the UI (including Present Value and Scale) from a BACnet integration with an accumulator that exists in a BACnet device.

Note: A BACnet accumulator is mapped at the engine through the Insert Point wizard.

To add an accumulator from a BACnet device on an IP BACnet integration:

  1. From the SMP UI or SCT UI, add a BACnet integration.
  2. Add a BACnet device type compatible with the field device that contains an accumulator.
  3. Map the accumulator at the engine (that is, add the Accumulator point to the mapped BACnet device using the Insert Point wizard).

MS/TP Field Bus

(BACnet Device)

Provides integration of BACnet controllers with supervisory controllers through a BACnet accumulator mapper. This object provides information on the UI (including Present Value and Scale) from a BACnet Integration with an accumulator that exists in a BACnet device.

Note: A BACnet accumulator is mapped at the engine through the Insert Point wizard.

To add an accumulator from a BACnet device on an MS/TP field bus:

  1. From the SMP UI or SCT UI, add an MS/TP field bus.
  2. Add a BACnet device type compatible with the field device that contains an accumulator.
  3. Map the accumulator at the engine (that is, add the Accumulator point to the mapped BACnet device using the Insert Point wizard).

MS/TP Field Bus

(FEC Family BACnet Device)

Provides integration of pulse meters integrated to the Dry Contact Pulse (MISC-MTR) binary input of an FEC family BACnet device. CCT creates an Accumulator object for the pulse meter input of the FEC family BACnet device. This FEC accumulator is shadowed by the engine.

Note: An FEC accumulator object is mapped at the engine through the Insert Point wizard.

To add an accumulator from an FEC family BACnet device on an MS/TP field bus:

  1. From the SMP UI or SCT UI, add an MS/TP field bus.
  2. Add an FEC family BACnet device compatible with the field device that contains a visible accumulator (defined by CCT).
  3. Map the accumulator at the engine (that is, add the Accumulator point to the mapped field device using the Insert Point wizard).

N2 Trunk

(N2 Device)

Provides integration of the wide variety of N2 controller binary input/pulse counters, resulting in a consistent interface for point mapping any N2 controller types.

Note: An N2 accumulator or pulse counter is mapped at the engine through the Insert Point wizard.

To add an accumulator from an N2 device on an N2 trunk:

  1. From the SMP UI or SCT UI, add an N2 trunk.
  2. Add an N2 device type compatible with the field device.
  3. Map the accumulator (Accumulator or Pulse Counter type) at the engine (that is, add the Accumulator point to the N2 device using the Insert Point wizard).
  4. Define the Rollover Limit:
Note:

You must set the rollover limit in the N2 accumulator to match the rollover limit of the N2 field device selected. For example, AHU or UNT devices have a rollover limit of 4,294,967,295. A DX-9100 CNT point has a rollover limit set by the GX-9100 configuration tool. An XT-9100 or XTM CNT point has a rollover limit set by either the GX-9100 configuration tool or XTM configuration tool.

Map BI7 or BI8 for an AHU, BI4 for a UNT or VAV, or ADI network point types for a DX-9100 or XTM.

Other Integrations

(For Example, LonWorks, N1, VND, and XL5K Devices)

Allows you to monitor the increasing pulse count from any attribute that has an incrementing value. This provides greater flexibility for creating accumulator objects.

Note: An object with an attribute that has an incrementing value is mapped at the engine through the Insert Object wizard.

To add an accumulator from a device on other integrations:

  1. From the SMP UI or SCT UI, add the desired integration.
  2. Add a device type compatible with the field device.
  3. Map the accumulator at the engine (that is, add the Accumulator object using the Insert Object wizard).
  4. Reference a value that continually counts up until the value wraps back to zero when it passes the Rollover Limit value defined in the accumulator object.

The following figure illustrates the interaction between the different types of accumulators and the accumulator in the engine, showing the key attributes and functionality.

Figure 1. Accumulator Interaction

An FEC family BACnet device that resides on the MS/TP field bus has a binary input with a Dry Contact Pulse signal (MISC-MTR) created in CCT. This provides an FEC accumulator. A BACnet device that resides on either the BACnet integration or the MS/TP field bus has an accumulator. Both the FEC accumulator and BACnet accumulators have BACnet Prescale, Units, and Limit Monitoring Interval attributes that interact with the accumulator in the engine through the prescaled Present Value.

An N2 controller resides on the N2 trunk, and has an attribute that counts. Similarly, other devices that reside on other integrations (for example, a LonWorks device on a LonWorks integration) that have attributes that count may take advantage of the accumulator functionality. The accumulator in the engine uses the count value.

The accumulator in the engine uses the prescaled Present Value or counts from the devices with the key engine accumulator attributes listed in the figure. For details on the calculations used by and functionality of these attributes, see the Accumulator Attributes section.

The accumulator’s prescaled Present Value is used by the Pulse Meter, DLLR, or IEIEJ objects. You can trend the prescaled Present Value, which may then be used by Energy Essentials. You also can trend the accumulator’s Pulse Rate, Scaled Present Value, or Value Before Change attributes.

Note: The prescaled Present Value, as well as its associated commands and attributes (Preset Value, Value Before Change, Max Value, Value Set), do not necessarily have the same units as Scaled Present Value or the Units attribute.

The header of the focus window shows the Scaled Present Value after the scale factor has been applied to the Present Value, as well as the units that apply to the Scaled Present Value.