Overview of Managed Meters
Managed meters are logical entities that are responsible for handling data for generating reports. These meters are used to calculate the consumption of energy, electricity, gas, water and so on across various facilities, such as buildings, business complexes and manufacturing plants. Using the Desigo CCManaged Meters you can configure the managed meters.
To configure a managed meter, you must associate a trend log object, such as a metering point, which acts as a parameter to capture the meter readings. You must also provide the following information:
- Physical location of the meter in the facility.
- Logical (CNS) path of the meter in the management station.
- Purpose for installing the meter, such as calculating the consumption of electricity, water, oil, gas and so on.
- The units of measurement in which the meter will record values.
- The maximum meter reading.
- Offset and notification profiles.
You also have an option of associating a second metering point with a managed meter in the Source Meter expander in the Managed Meters application. This may be essential if the meter is used for dual purposes. For example, you have a cooling plant in which you want to calculate the quantum of water consumed, as well as calculate the total energy consumed in the cooling process. In this case, you can configure a managed meter so that you have one metering point that acts as a primary point to calculate the total quantum of water consumed by the cooling plant, and a second metering point that calculates the total amount of energy consumed by the plant.
Using this application, you can generate reports from historized data. This data includes the physical path of the object that is associated with the managed meter, the different views in which the meter is configured, the media units in which the meter records values, and the offset values.
There can be situations where a managed meter displays incorrect values, such as a negative value or a zero. You can correct this from the Manual Correction application.
Managed meters are covered by a license. The number of meters that you can create depends on the quantity provided by this license. If the number exceeds this quantity, the management station will run in Courtesy mode.
The following are the three possible managed meter irregularities that can be detected:
- Irregularities due to meter roll over - This irregularity is detected when the current meter reading is close to the maximum meter reading.
- Irregularity due to a decrease in the meter reading - This irregularity is detected when there is a decrease in the meter reading which will result in negative consumption.
- Irregularity due to zero meter reading - This irregularity is detected when the meter reading is zero, which results in negative consumption.
In order to detect these irregularities, you can create and configure a reaction that automatically detects meter irregularities on its execution. You can also manually detect irregularities by specifying the number of days for which you want to detect the meter irregularities.
When the reaction executes at the specified time, it detects any irregular meter readings for all the managed meters. If any irregularities are observed during this time period, an event is raised.
If the irregularity has occurred due to a decrease in the meter reading or due to zero meter reading, it is reported as a fault event. However, if the irregularity has occurred due to the warning limit being exceeded, it is reported as a status event.
The properties of the managed meter display more information about the detected irregularity. Some examples of such properties are Irregular Reading which is set to True whenever there is an irregularity detected, Irregular Reading Time that displays the date and time of the irregular reading, and so on. However, in order to detect the irregularities, you must ensure that the meters have their notification profile set to either Meter rollover, Meter reading decrease, or Zero meter reading.
In order to treat the event, you must first correct the irregularity from the manual correction application and then run the irregularity check once again.
NOTE:
If the managed meter has irregular readings, then for such a meter, the consumption cache will not be generated from the date on which the meter readings are irregular, till the irregularity is rectified. The irregular readings can be corrected from the manual correction application.
Following is a list of meter properties that display in the Operation tab and their description.
Meter Property | Description |
Irregularity Checked | Date and time when the irregularities of all the configured managed meters were checked. |
Irregular Reading | Displays Yes if the meter has an irregular reading. If there were no irregularities detected, No displays. |
Irregular Reading Time | Date and time of the irregular reading. |
Meter Reading | Most recent meter reading when the irregularity check was done. |
Input Media Unit | Unit in which the meter reading is stored. |
Meter Reading Time | Date and time of the most recent meter reading. |
% Near Maximum Reading | Percentage of the most recent meter reading with respect to the maximum meter reading. For example, if the maximum meter reading is 1000 and the most recent meter reading is 750, then this property value will be 75%. If the maximum meter reading is not specified, then the maximum limit of the GMSreal type shall be considered a the maximum meter reading. |
Warning Limit Exceeded | Displays Yes if the most recent meter reading has exceeded the warning limit set in the notification profile for the meter roll over setting. Displays No, if the most recent meter reading is below the warning limit set in the notification profile for the meter roll over setting. For example, if the maximum meter reading is 1000, the warning limit set in notification profile is 95% and the most recent meter reading is 960, then this property value will be Yes. |
Consumption | Consumption value of the managed meter before an irregularity was detected in the meter |
Output Media Unit | Unit in which the consumption value is displayed in reports. |
Consumption Time | Date and time of the consumption. |
The concept of Offset applies when calculating energy consumption. Offset is applied in situations where the managed meter has reached its maximum value as specified in the Max Meter Reading field and the meter reading restarts from 1, or when the managed meter is physically replaced due to defect, upgrade, or buffer overflow.
The Offset is specified in the Offset field in the Managed Meters application.
The following examples will help you better understand this concept.
Example 1:
You have a managed meter with 10,000 specified in the Max Meter Reading field. The meter has reached 10,000 and it restarts from 1 and continues until 1000. At this point, if you take the meter reading, the value will be 1000; however, the energy consumed from the start is11,000, since the meter has already crossed 10,000. Therefore, in order to arrive at the exact energy consumption value, you must specify the Offset with a valid date and time.
Example 2:
You have a managed meter with 10,000 specified in the Max Meter Reading field. The meter has reached 10,000 and it restarts from 1. You specify 10,000 as the Offset and the value displayed on the meter is 1000. If you take the meter reading, the value will be 11000, since the value of the Offset is added to the current meter reading to get the exact reading. Also, the value calculated for energy consumption will be accurate. When the meter rolls over the second time and the reading restarts with 1, the value that you specify as the Offset must be 20,000, since the meter has rolled over two times. Similarly, after the third rollover, the Offset value will be 30,000 and so on. Therefore, the Offset value on every rollover is equal to the sum of the present Offset value and the Max Meter Reading.
