Flow Computer Tags

Like a station tag, each Flow Computer tag will create many I/O tags that count towards your license limit. The number will vary according to configuration.

This tag provides a complete interface to a flow computer (EFM device) for logged data, process data, alarms and events. The Flow Computer tag is the basic building block of the Oil & Gas Solutions approach to EFM devices. It allows a complete field I/O device (flow computer) to be defined as a single tag structure. This Flow Computer tag will automatically generate child tags to perform the necessary device communication, data reading and logging for compliance data, as well as providing a way to define the device-specific I/O tags used for process monitoring and control functions.

There are many configuration options that control which child tags start and how those child tags operate. Flow Computer Overview and Design describes the details of creating a Flow Computer tag. This topic describes each of the child tags of the Flow Computer tag.

One Flow Computer tag is required for each field I/O device (RTU).

Related information:

Best Practices for Tags

Flow Computer Overview and Design

Flow Computer properties ID tab

In a Flow Computer tag, the Name + Description parameters are used to identify the location of the well.
The Area + Alarm Notification Area parameters are used for grouping, filtering, and roster control

Name & Description

Together, these parameters define a unique identifier for the equipment. In some jurisdictions, the description is typically set to the LSD Legal Subdivision address. or UWI Unique Well Identifier coordinates, but you are free to use whatever value makes sense for your system.

Area & Alarm Notification Area

The area parameter is used to group similar tags together, such as all wells within a given region. An Alarm Notification Area can be defined so that separate rosters can be defined within one region, or so that wells from several fields can use one roster.

The Alarm Notification Area property is inherited by several of the Polling Driver children of this tag and then by any I/O or alarms below those. Child tags that are not expected to generate alarms will inherit the Area property.

If no Alarm Notification Area property is defined, all child tags will default to the Area property.

Flow Computer properties I/O tab

Options within this tab vary depending on the selected Device Type. Several parameters are common to most device types and are described here first:

Configuration Address Override File,
Read Address Override File,
Write Address Override File,
CFX Mapping Override File

Not available for all device types.

Not all values read by the flow computer are represented by tags. Some configuration information, such as the gas composition, orifice, or pipe detail, is read by the Meter Run tag and saved as a single configuration record.

The addresses used to read and write this information are usually standard for a given device type, but if you need to change them you may do so by providing a new mapping CSV file to override the standard version. See CSV Override Files for Flow Computers .

The CFX Mapping Override is used to customize the mapping of values in the flow computer to values in a CFX report. For example, some flow computers might represent the pipe material of "Monel" with a 1, while others use a 4. When VTScada prepares the CFX file, it uses this mapping file to figure out which numerical values represent which physical values.

VTScada already knows how to handle the mapping of most device types, and thus this parameter is not required. This setting is primarily used for devices such as those using the Bristol protocol, which have no standard flow computer firmware.

Device Clock Time Zone

Select the time zone that the device uses in order to convert the time-stamped data from the device into UTC for storage in the VTScada historian. Regardless of the time zone selected with this option, the driver assumes that the device does NOT adjust its clock for daylight savings time (DST).

Defaults to the server's time zone, but may be set to use the device's clock if that is configured for UTC, otherwise any time zone where the device is located.

Station Address (This and station address mode are not used for all types)

The station address of the Modicon programmable logic controller. By default, the PLC Address field is set to 1.

An expression may be used to provide the address if needed. This may be required on a network where the address varies depending on the workstation where the tag is running.

Note that, to create a valid expression for an address that contains non-numeric characters, you must enclose the address in quotation marks. e.g. "31.0.0.0" See: Modbus Plus PLC Addressing.

Station Address Mode

Use to limit the range of allowed addresses. Select according to your hardware.

Should only be adjusted if the Flow Computer/POC has been configured to use one of the specific addressing modes.

Standard Address ... 1 - 255 according to Modbus Protocol. Extended addressing ranges are not supported.

Lufkin ELAM Address ... 1 - 2295

TeleBUS Extended Address ... 1 - 65534

Device Type

Device types are grouped by common options for configuration. Expand the type matching your system for relevant detail.

Bristol

Local Address

Local address of the RTU (1 – 127).

Delete Audit Log on Read

When selected, the audit log (also known as the alarm and event log) is cleared from the RTU every time it is read. This may result in more efficient audit log reads when the log is full.

Bristol Network Tag

This identifies the Bristol Network tag that is to be used by all of the flow computer’s Bristol drivers. As a general rule, there should be one Bristol Network tag for each Port tag in the system that is used by Bristol drivers.

Bristol Master RTU

The RTU that is a level above the current flow computer RTU in the Bristol BSAP network hierarchy. This is only relevant for Bristol RTUs that are not in direct communication with the VTScada server but are instead in communication with an intermediary Bristol RTU on a higher level in the network

Override Files

Because Bristol RTUs do not all use a single industry-standard flow computer program, Bristol Flow Computer tags in VTScada make extensive use of address override files.

By default, files for one type of ControlWave program are selected (sample address: @GV.RUN1_PIPE_DIAM). Files for another type of ControlWave program (sample address: @GV.WELL1_PIPE_DIAM) and for an example 3305 program (sample address: A03.PIPE.DIAM) are included with the Oil & Gas Solutions Layer installation. These files can be found below the Oil & Gas Solutions VTScada directory, (C:\VTScada\O&G Solutions\CSV_Overrides). Ensure that you select the set of files with the correct set of addresses for your RTU’s program. If none is a match, choose a set to use as a template for creating your own custom files that work with your custom program. See CSV Override Files for Flow Computers .

Also, note that not all Bristol flow computer programs necessarily use the same history files. Be sure to check the History Logs tab of the Flow Computer tag configuration to ensure that the addresses are correct.

Flow Computer properties Communications tab

The Communication tab sets up a number of settings common to all field I/O devices that are used by the Flow Computer tag and child tags.

Port

Select the communication port used by the field I/O device driver. For most SCADA protocols (including Enron Modbus and ROC) multiple devices may share a single port to create multi-drop communication links. The port type selected here may be any of the standard VTScada port types:

Direct connected serial port
Dial up modem connected serial port
TCP/IP networked port
UDP/IP networked port

Time-Out Limit

The length of time, in seconds, that the driver will wait for a reply from the device when in query response mode.

Retries

The number of communication attempts that will be made by this driver if there is no reply to the initial message. An error will be declared after this number has been exceeded.

Process Data Hold

Select this option to have the process I/O tags hold their last read value in the event of a communication failure with the field I/O device.

Disable All Polling

If selected, all polling for this flow computer will be disabled, regardless of the data read settings or the process I/O scan interval settings.

Polling Group

Sets the polling group in all of the subordinate polling drivers. See the Polling Driver section in the standard VTScada help documentation for more details.

Read Configuration Data

Select the frequency and timing for when configuration data will be read. Options for timing vary according to the selected frequency of reads.

Read Daily Logged Data

Select the frequency and timing for when daily logged data will be read. Options for timing vary according to the selected frequency of reads.

Read Hourly Logged Data

Select the frequency and timing for when hourly logged data will be read. Options for timing vary according to the selected frequency of reads.

Read Alarms and Events

Select the frequency and timing for when alarm and event data will be read. Options for timing vary according to the selected frequency of reads.

ads.

Process I/O Scan Interval

Sets the poll interval (in seconds) for the process I/O data read from the field I/O devices.

This rate can be overridden by the manual polling and fast polling schemes used on some of the graphics displays.

Communications Statistics Reset Schedule

The Flow Computer tag tracks several communications statistics for its child drivers (good polls, last error code, etc.). This parameter determines how often those statistics are reset to zero.

Auto-Synchronize RTU Clock

Sets the schedule at which VTScada will attempt to synchronize the device’s internal clock to match the server’s clock. Note that this will account for the device’s time zone, as set in the Device Clock Time Zone parameter on the Communication tab. (Automatic synchronization may not be available for all device types.)

Clock Sync Deadband

The amount by which the RTU clock must differ from the server’s clock before VTScada will attempt to set the RTU’s clock.

To avoid conflicts if a clock is changed over the threshold of a contract hour, there is logic built in so that the clock will never be automatically set back over the threshold of an hour. For example, if the RTU clock is off by five minutes it will not be corrected from 11:03 to 10:58, but rather VTScada will wait and correct it from 11:06 to 11:01. For this reason, if the RTU clock is off by an hour or more it will not be automatically synchronized and should be explicitly reset through another method.

Flow Computer properties Flow Meters tab

Enable up to 11 Meter Run Tags in the Flow Computer tag. For each meter run that is enabled, a number of child tags are started in the Flow Computer to configure, and gather and display information for that meter run.

Enable

If selected, the appropriate Meter Run tag and its child tags will be created as a child of the flow computer.

Meter Properties Button

Open the properties dialog of the associated Meter Run tag. Meter-specific settings are configured directly in their tag. See Meter Run Tags for more information.

The Flow Computer tag offers a convenient convergence point for the management of your first 11 meter runs, but you also have the option of configuring your Meter Run tags manually anywhere in the application. If your Meter Run tags are not auto-generated by the Flow Computer tag, even if the MR number configured is between 1 and 11, you will not be able to open their properties dialog or enable/disable them from this tab.

Your application is not limited to 11 Meter Runs. Additional Meter Run tags can be created manually.

Flow Computer properties: CFX Setup tab

"CFX" is "Common File Exchange". This is a proprietary file format owned by Flow-Cal which is used to report on the production of gas wells.

VTScada uses the parameters on this tab only when writing a CFX Hourly Report or a CFX Daily Report. The parameters are written directly into the appropriate section of the CFX file.

Flow Computer properties Misc. tab

The Misc. tab is used to configure how the Flow Computer will appear on standard VTScada map displays. If left blank, the default values provide access to a set of standard displays described in Flow Computer Displays.

Latitude

Set the latitude for the Flow Computer in decimal degrees. If not defined, the Flow Computer will not appear on map displays. For this setting, positive numbers define locations east of the prime meridian and negative numbers define locations west of the prime meridian. To set a specific location on a map directly, use the standard VTScada “Update Site Location” tool.

Longitude

Set the longitude for the Flow Computer in decimal degrees. If not defined, the Flow Computer will not appear on map displays. For this setting, positive numbers define locations north of the equator and negative numbers define locations south of the equator. To set a specific location on a map directly, use the standard VTScada “Update Site Location” tool.

Custom Tab Label

Allows you to define a tab label on the built-in standard display for displaying the Custom Page Tab.

Page to Display in Custom Tab

Set the page to display on the built-in standard display that is specific to this Flow Computer. This can be a parameterized page and will be handed the tag value of the Flow Computer tag as its first parameter. Used this way, a single page can be used for multiple Flow Computers on their standard display.

Standard Site Dialog Override

If a page is selected for this parameter, that page will be shown instead of the standard flow computer site details page when a Flow Computer tag is clicked on the site list or the slippy map.

Hide Gas Configuration Tab

Selecting this box will hide the configuration tab on the standard flow computer site details page. As an example, it is appropriate to select this box for flow computers measuring liquids.

Security Privilege - Write Configuration Data to RTU

Set the security privilege required to write configuration changes to the field I/O device. If not selected, no security privilege is required for this action.

Security Privilege – Polling

Set the security privilege required to perform a demand poll of the RTU.

Historian

Selects the historian tag to use in conjunction with the data logging of all child tags. In most cases this can be left as the default, “System Historian”. See standard VTScada documentation for more details.

Display as List of Meters

When selected, the flow computer will appear on the sites page and slippy maps as a list of individual meter runs rather than as a single unified flow computer.

Custom Meter Displays Override Site Dialogs

When selected, clicking on the meter run on the sites page or slippy map will bring up the custom page selected on the Meter Displays tab rather than the standard site dialog with that page as one of the tabs. This setting is applicable only when the Display as List of Meters option is selected.

Contract Hour

Sets the contract hour for the PVR Report. It is used by all meters in a Flow Computer. This field expects the contract hour to be in the form of a single number. (For example, enter 8 and not 8:00:00).