Realflo Analog Input points are used to process gas, liquid or water flow calculation data in Geo SCADA Expert (see Configure Geo SCADA Expert to Monitor Realflo Calculation Data). (To process any other data on a Realflo controller, configure a ‘standard’ analog or digital point, rather than a Realflo Analog Input point.)
Use the fields at the top of the Analog Point tab on the SCADAPack Modbus Realflo Analog Input Point Form to configure the point’s common properties. Fields that are specific to Realflo Analog Input points are explained below. For properties that are also common to other points on the SCADAPack Modbus driver, see Configure Common Point Properties in the Geo SCADA Expert Guide to the SCADAPack Modbus Driver.
- Outstation—This field is for information only. It displays the name of the controller on which the point is located.
Use the Flow Run field (see below) to specify the Flow Run with which the Realflo Analog Input point is associated. The Outstation (controller) is inherited from the Flow Run and is displayed in this field the next time that the configuration is saved.
- Flow Run—Use to specify the Flow Run with which the point is associated. Use the browse button to display a Reference browse window. Select the required Flow Run from the window.
- Address—This field is for information only. It displays the address that defines the location of the item of Flow Run data that the point reads.
Geo SCADA Expert allocates the address automatically, in relation to the Source and Item (see below) that are specified for the point. Once the Source and Item have been specified, the Address is inherited from those properties and is displayed in this field the next time that the configuration is saved.
- Source—Use to define the source of the data in the Flow Run. Use this field in conjunction with the Item field (see below) to specify the Item of Flow Run data that a Realflo Analog Input point represents.
The possible Source options are:
- Accumulation—A Flow Computer is able to accumulate data about the gas, liquid or water flow over the present and previous day and month. Select this option if the point is being used to read an item of data from the Flow Computer’s Accumulated Reading register.
Geo SCADA Expert retrieves any Accumulation point values at the frequency specified for the Flow Run’s Current Scan (see Configure the Scanning Properties).
- Input—The point is used to read one of the inputs that is associated with either the Flow Run’s configuration or its Flow Calculation. The actual Flow Run and Flow Calculation properties are specified on the Flow Run Form (see Configure the Flow Run Properties, or see Flow Calculation Properties (Gas Flow Run), as appropriate.)
Geo SCADA Expert retrieves any Input point values at the frequency specified for the Flow Run’s Current Scan (see Configure the Scanning Properties).
- Flow Calculation—The point is used to read an item of Flow Calculation Data. For the type of Flow Calculation that the Flow Run performs and the properties that are associated with that calculation, see Flow Calculation Properties (Gas Flow Run).
Flow Calculations continuously recalculate in a Flow Computer. Geo SCADA Expert retrieves any Flow Calculation point values at frequency specified for the Flow Run’s Current Scan (see Configure the Scanning Properties).
- Compressibility Calculation—Available only for points that are associated with Gas Flow Runs. The point is used to read an item of Flow Run Compressibility Calculation Data. For the type of Compressibility Calculation that the Flow Run performs and the properties that are associated with that calculation, see Compressibility Calculation Properties (Gas Flow Run).
Compressibility Calculations continuously recalculate in a Gas Flow Computer. Geo SCADA Expert retrieves any Compressibility Calculation point values at frequency specified for the Flow Run’s Current Scan (see Configure the Scanning Properties).
- Density Calculation—Available only for points that are associated with Gas Flow Runs. The point is used to read the Heating Value that is associated with the Flow Run’s Compressibility Calculation. The raw Heating value that is read into Geo SCADA Expert is displayed on the Compressibility Calculation tab of the Flow Run Form (see General NX-19 Calculation Properties, or see AGA-8 Relative Density and Heating Value Properties).
Density Calculations continuously recalculate in a Gas Flow Computer. Geo SCADA Expert retrieves any Density Calculation point values at frequency specified for the Flow Run’s Current Scan (see Configure the Scanning Properties).
- Daily Flow History—The point is used to read data from the daily logs that are produced by the Flow Compute. Each Flow Computer can retain 35 days-worth of daily logs.
Geo SCADA Expert retrieves this point data at the frequency specified for the Flow Run’s Daily History Scan (see Configure the Scanning Properties).
Always ensure that Historic is enabled for a Realflo Analog Input point that has a Daily Flow History Source, so that Geo SCADA Expert stores the data historically. For information on enabling Historic data storage, see Defining Historic Details for a Point in the Geo SCADA Expert Guide to Core Point Configuration.
If a Realflo Analog Input point with a 'Daily Flow History' Source is added to an existing system, when Geo SCADA Expert first retrieves the data for that point, it will read all of the Daily History data that the Gas Flow Computer has in its database for that Flow Run. System performance may be affected while the retrieval of up to 35 days’ worth of Daily historic data is in progress.
For optimum system performance, we recommend that all points that are to have a ‘Daily Flow History’ source are configured and placed online at the same time.
- Hourly History Data—The point is used to read data from the hourly logs that are produced by the Flow Computer. Each Flow Computer can retain 35 days-worth of hourly logs.
Geo SCADA Expert retrieves this point data at the frequency specified for the Flow Run’s Hourly History Scan (see Configure the Scanning Properties).
Always ensure that Historic is enabled for a Realflo Analog Input point that has an Hourly History Data Source, so that Geo SCADA Expert stores the data historically. For information on enabling Historic data storage, see Defining Historic Details for a Point in the Geo SCADA Expert Guide to Core Point Configuration.
If a Realflo Analog Input point with an ‘Hourly History Data’ Source is added to an existing system, when Geo SCADA Expert first retrieves the data for that point, it will read all of the Hourly History data that the Gas Flow Computer has in its database for that Flow Run. System performance may be affected while the retrieval of up to 35 days’ worth of Hourly historic data is in progress.
For optimum system performance, we recommend that all points that are to have an ‘Hourly History Data’ source are configured and placed online at the same time.
- Batch Records—The point is used to read data from batch records that are produced by the Flow Computer.
Always ensure that Historic is enabled for a Realflo Analog Input point that has a Batch Records Source, so that Geo SCADA Expert stores the data historically. For information on enabling Historic data storage, see Defining Historic Details for a Point in the Geo SCADA Expert Guide to Core Point Configuration.
If a Realflo Analog Input point with a 'Batch Records' Source is added to an existing system, when Geo SCADA Expert first retrieves the data for that point, it will read all of the Batch Records data that the Gas Flow Computer has in its database for that Flow Run. System performance may be affected while the retrieval of Batch Records data, is in progress.
For optimum system performance, we recommend that all points that are to have an ‘Batch Records’ source are configured and placed online at the same time.
- Accumulation—A Flow Computer is able to accumulate data about the gas, liquid or water flow over the present and previous day and month. Select this option if the point is being used to read an item of data from the Flow Computer’s Accumulated Reading register.
- Item—Use to specify the individual item of Source data that a Realflo Analog input point represents (for example, the Mass density at flow conditions). The options vary, depending on:
- The type of Flow Run with which the point is associated (see above)
- The type of data Source that the point represents (see above)
- (In the case of Gas Flow Runs) The Type of Gas Flow Calculation
- The Meter Type (see Coriolis Meter Properties)
- (If applicable) the Meter Input Type (see Meter Input Properties).
Select the combo box to display a list of options. Select the required option. For a list of the Source and Item of data that a point can represent, see (as applicable):
(The above topics describe how information about the properties appears when viewed as status attributes.)
- Scan Group (Confidence Interval)—Use the combo box to specify the Scan Group with which the point is associated. The Scan Group determines the frequency with which the driver updates the server with the current value for the point. This provides confidence that all is well between Geo SCADA Expert and the direct controller, as the point is updated in the database at the Scan Group rate, regardless of whether the point has changed in the controller.
With Realflo Analog Input points, you should specify a Scan Group that has an interval that is a multiple of the Flow Run’s Current Scan interval (see Configure the Scanning Properties). Realflo Analog Input points are polled in a block at the Flow Run’s scanning intervals, rather than individually. As such, a Realflo point’s Scan Group interval does not trigger a poll for data. Therefore, if a Scan Group is specified that has an interval that is faster than the Flow Run’s Current Scan interval, the point will still only be updated at the latter rate—the driver will not schedule extra polls if the Scan Group’s rate is faster.
Specify the frequency of each Scan Group on the Scan Parameters tab of the associated Channel Form (see Define Intervals for Timed Current Data Updates in the Geo SCADA Expert Guide to Advanced Drivers).
The Scan Group (Confidence Interval) combo box does not apply if the server only retrieves logged, but not current data for a point. (This occurs when a point’s DLOG Only check box is selected—see Log Point Data on SCADAPack Controllers in the Geo SCADA Expert Guide to the SCADAPack Modbus Driver. On a Realflo Analog Input point, this also occurs when the point’s Source is specified as either Daily Flow History or Hourly History Data (see above).)
- Data Type—This field is for information only. The Data Type is determined by the type of data Source and Item of Flow Run data that the Realflo Analog represents. The Data Type specifies the format of the raw data.
Examples:
In order to assess the amount of gas, liquid or water that has been used during the past month, you might configure a Realflo Analog Input point to have the following properties:
Source: Accumulation
Item: Flow volume in current month
In order to assess the current flow rate, you might configure a Realflo Analog Input point to have these properties:
Source: Flow Calculation
Item: Flow volume rate