Accumulator Attributes - Metasys - LIT-12011964 - Software Application - System Configuration Tool - 13.2

Metasys SCT: System Configuration Tool Help

Brand
Metasys
Product name
System Configuration Tool
Document type
User Guide
Document number
LIT-12011964
Version
13.2
Revision date
2020-01-21
Language
English

This object contains attributes common to many Metasys system objects.

Notes for Anti Spike:

  • Any mapper object used to deliver a raw count value to the Accumulator must provide an unreliable value during startup if the value was not updated from the field controller at the time it is read by the accumulator. For example, a LON counter mapped as an AI point object reports as unreliable until it reads a value from the field controller. If the LON counter is mapped as an AO point object, it reports as reliable even if the value is not initialized, causing improper values to be recorded at the accumulator. This may occur regardless of the value of Anti Spike.
  • Any mapper object used to deliver a raw count value to the accumulator must be allowed to count up without disruption from manual commands, schedules, interlocks, or any other function that may change its value outside the normal counting process. Any such changes may cause the Accumulator to record improper values regardless of the value of Anti Spike.
  • When replacing the input device, set Anti Spike to True before the replacement is brought online for the first time. This setting prevents the accumulator value from spiking upward due to an uncontrolled count value change at the input device. Failure to set Anti Spike to True can upset the accumulator value. You can use a manual preset to restore the correct value after the new device is online.
Table 1. Accumulator Object Attributes
Name / View Group

Attribute ID Writable (W) Configurable (C)

Attribute Description
Input Ref -- Engineering Values

545 C

Identifies the attribute reference to the object property that is the pulse count input for the Accumulator object (for the Other integrations type: LonWorks, N1, VND, and XL5K, for example). This must be a continuously increasing positive numeric attribute of another object, such as the present value of a totalization extension to an analog meter.

Max Value -- Engineering Values

65 W C

Indicates the maximum value allowed for the Present Value. The Present Value is not allowed to exceed this value, and wraps back to zero when this value is passed. Accumulation does not stop.

Note: If the present value of the Accumulator object is being trended and its data is sent to the ADS/ODS repository, change this value to 32,767 so that the historian database (JCIHistorianDB) can properly store its value.
Limit Monitoring Interval -- Engineering Values

182 W C

Specifies the monitoring period in seconds for determining the Pulse Rate. The Pulse Rate is the number of pulses received during the previous Limit Monitoring Interval period.

Rollover Limit -- Engineering Values

823 W C

Represents the actual rollover value of the input pulse counter. This attribute applies to N2 and Other Accumulators. This value is used to compute a change rate, which is added to the Accumulator property to calculate the Pulse Rate and Present Value.

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 the either the GX-9100 configuration tool or XTM configuration tool.

Units -- Display

117 W C

Contains the engineering units for the Scaled Present Value attribute.
Internal Units -- Display

3432 W C

Contains the engineering units for the Present Value, Value Set, Max Value, and Value Before Change attribute.
Display Precision -- Display

661 W C

Determines how many decimal places to display in the Scaled Present Value.
Anti Spike -- Filter Setup

722 W C

When True, causes the object to use the first good input count value received after previously being unreliable as strictly an initial value. Any archived or last known value for input count is ignored. If the input device resets or loses power, uncontrolled changes to the input count value are filtered out and do not result in a spike in accumulator values. Use this setting in cases where the input device is not known to preserve its count value over a power loss (for example, in a LonWorks integration an LN-PRG20 GPI, and in an N2 integration a UNT).

When False, causes the object to use the first good input device count value received after previously being unreliable as a valid change from the archived or last known value for input count. This means the first good input device value is used to catch up on any counts that were missed while the input device was unable to communicate due to either an NAE restart or communication loss. Do not set this value to False unless the input device is known to preserve its count value during a power loss (for example, in an N2 integration, an XTM-105 with a XPB-821 or in a LonWorks integration LN-PRG300-2, LNPRG400-2, LN-PTRG500-2, LN-PRG600, or in a vendor integration BTR Netcom GmbH device LC14 [Model # 11045013-US], an IDEC SX5L-SBCN081, or a WATANBE Electric Industry WRBC-DI16F-A002).

Notes:
  • Any mapper object used to deliver a raw count value to the Accumulator must provide an unreliable value during startup if the value was not updated from the field controller at the time it is read by the accumulator. For example, a LON counter mapped as an AI point object reports as unreliable until it reads a value from the field controller. If the LON counter is mapped as an AO point object, it reports as reliable even if the value is not initialized, causing improper values to be recorded at the accumulator. This may occur regardless of the value of Anti Spike.
  • Any mapper object used to deliver a raw count value to the accumulator must be allowed to count up without disruption from manual commands, schedules, interlocks, or any other function that may change its value outside the normal counting process. Any such changes may cause the Accumulator to record improper values regardless of the value of Anti Spike.
  • When replacing the input device, set Anti Spike to True before the replacement is brought online for the first time. This setting prevents the accumulator value from spiking upward due to an uncontrolled count value change at the input device. Failure to set Anti Spike to True can upset the accumulator value. You can use a manual preset to restore the correct value after the new device is online.
Intrinsic Alarming Defined -- BACnet

569 W C

Indicates whether intrinsic alarming is enabled when the site is defined as a BACnet site. When intrinsic alarming is defined for accumulators on the MS/TP field bus, the pulse rate of the accumulated point can be monitored.

Device Type -- BACnet

31 W C

Contains a description of the physical device connected to the object.
Use Remote Alarming -- BACnet

853 W C

When the attribute Intrinsic Alarming Defined is set to True, determines where alarms for the object originate. If the remote integrated object contains attributes for originating alarms, then Use Remote Alarming defaults to True, causing the local mapper object to accept alarms from the remote integrated object that are routed to the NxE. If the remote integrated object does not contain attributes for originating alarms, then Use Remote Alarming defaults to False causing the local mapper object to originate alarms. When Use Remote Alarming is false, any alarms from the remote integrated object are ignored at the NxE. If the value of Use Remote Alarming is changed, a restart of the NxE may be required to assure correct operation.

Scale As Integer -- Scale

4692 W C

Indicates the power of ten to be multiplied with the value of the Present Value attribute to get Scaled Present Value. This attribute only applies if Scale As Float is zero. For example, when Scale As Integer is set to two, the Present Value is multiplied by 100; while setting Scale As Integer to -1 multiplies the Present Value by 0.1. When zero (the default value), the Present Value and Scaled Present Value are equal (see Scaled Present Value).

Scale As Float -- Scale

4693 W C

Indicates the floating conversion factor to be multiplied with the value of the Present Value attribute to calculate the Scaled Present Value for the chosen units. If set to zero (the default value), the Scale As Integer value is used and Scale As Float is ignored.

JCI Logging Object Reference -- Logging

4696 W C

Indicates the object (Johnson Controls proprietary reference) that resides in the same device as the Accumulator object which, when it acquires Logging Record data from the Accumulator object, causes the Accumulator object to acquire, present, and store the Logging Record data (that is, snapshot) from the underlying system. When the object specified by the Logging Object Reference issues the Get Monitor Data command, the Logging Record is acquired and updated.