Which Action listed below is completed at the drop off Workstation

4.8 SCADA Operator Workstations

Workstations at the MCC and SCC are each designed to include one PC with a number of display screens. The operator workstations provided for the SCADA system support the operator interface and real-time and archival system functions for the SCADA system.

Operator workstations are used to access the process information database of the SCADA, historical data, and data relating to pipeline application software [PAS], and RTUs. Each operator workstation is connected both to SCADA LANs and to the user interface to allow the user to interact with the information in the SCADA system. A typical operator workstation for a gas pipeline is the main interface for all SCADA system functions and may include the following:

Graphical displays showing the process conditions of the pipeline

Trends of selected process variables

Alarm and event management including alarm acknowledgment

Process trends and analysis displays

Commands and controls to change the operating state of the pipeline facilities such as opening or closing of valves

Summaries and reports

System maintenance and configuration changes

Programming and system-level access to the servers

Intelligent cause and effect displays for the station logic with “what-if” analysis

Gas management system [GMS] displays

PAS displays

SIS displays

Displays related to corporate geographical information system

Safe start up and shut down guidelines

Diagnostics of the system up to card level and instrumentation including system-malfunction indications

Calibration and tuning displays

Asset manager

Report view and print

Communication error displays.

10.2.2 Functionality of Operator Workstations

The operator workstations are used for monitoring all system operations and for effecting control actions and parameter adjustments. These operator workstations are generally referred to as ‘clients’ since they obtain their current and historical data from the ‘server’ computer. There are normally multiple operator workstations, as illustrated in Figure 10.2, each of which contains all of the process graphic displays and historical trend displays for the system. Users of the SCADA system can log into the system through these workstations.

Some of the operations performed through the Operator workstations are listed below; more details about the displays required for these actions will be provided later in this chapter:

Logging on and off the system using passwords and user names

Invoking process displays to view the operations throughout the system

Effecting control modes for various equipment in the system; for example, Manual and Automatic modes, placing equipment in or out of service

Changing setpoint parameters, with appropriate security allowance

Effecting manual control actions for equipment, such as start/stop and open/close

Viewing historical trend displays and transferring data to other files for exporting

Viewing the current alarm summary to identify alarm conditions requiring attention

Viewing the alarm/event summary to view the chronological series of events.

The operator workstations provide the user interface or HMI to the SCADA system. Users can effect control over the equipment, as well as invoke displays which show current and historical information about any aspect of the SCADA system.

4.6 ESD Configuration and HMI

Typical configuration for an ESD system is shown in Fig. VIII/4.6-1. All field inputs from process variables and outputs to various actuators' MCC shall be connected to the ESD system with the help of an I/O bus. Depending on applicability there could be redundancies in various systems and the communication bus, as shown in Fig. VIII/4.6-1. Redundancies are shown with shadows. In the case of other systems where there are multiple systems, these are also shown with the help of shadows. Some systems [say an alarm system] may have an RS 485/422 link. In this configuration an attempt is made to highlight that the system is an independent system but can have an interface with other systems as well. At the top layer, Ethernet has been considered for HMIs, data server [if any], SOE, and other open systems on the same IEEE 802.3 Ethernet. There could be object linking and embedding process control [OPC] clients and these could be serviced by an ESD logic server, which will have dual or TMR redundancy built in.

The main operator interface to the ESD system is via an operator workstation located in the main control room and/or in an ancillary control room. Modern intelligent workstations are deployed for this service. The operator's functions and information exchange and changes through workstations shall include but not be limited to the following:

Display and control of process variables and actuators

Alarm acknowledgment and priority

Print initiations

Online generation of database

Online generation of displays

Generation of diagnostics and displays

Authenticated configuration changes [as applicable]

Tag identification and description

Type points

Point address

Scan frequency and priority

Signal processing

Engineering unit

Alarm limits

Constants

Fail safe position

Various displays:

Overview display of all shutdowns

System parameter configuration

Master menu

Summary display

Communication and system status display

Report summary

Various reports and logs:

Event log

Operator action report

Alarm log

Diagnostic report

Tag report

Historical report

Database cross-reference

The system normally have redundant communication channels and well-designed diagnostic systems to report. ESD is very important for process plants especially where there are chances of fire and explosion hazards such as in offshore plants.

The brief discussions on SIL, PE systems, and plant emergency systems are now concluded. With these concepts on SIS and SIL discussed in Chapters VII and VIII, respectively, it is time to look at various safety loop components with SIL ratings in SIS applications. These are covered in the next chapter.

19.12.6 Handheld Interfaces [Handheld Terminals or Handheld Communicators]

Using fieldbus technology, there is an unbroken digital chain from the field instruments to the operator work station. Therefore it is possible to diagnose, configure, and otherwise interrogate a device from the computer without having to venture into the field with a handheld. There is no need to find the right connection point at the junction box. The workstation runs the engineering and maintenance application that allows the user to configure and diagnose the devices and manage maintenance. Because these tools can be loaded with Device Description [DD] files that describe the devices in the field [or GSD in the case of Profibus], a single tool such as the Smar SYSCCON software can configure a plethora of devices from different manufacturers without interoperability problems. An additional advantage can be achieved using the Foundation Fieldbus. Because the control strategy programming language is part of the same specification as the communications for device configuration and maintenance, strategy building and device management, as well as network management, can be performed from the same single software tool. In the case of the Smar SYSCON software, this means that users can drag and drop from the strategy directly into the devices.

4.3.1.3 Control mode and operating mode switching

According to the needs of the operator, the following functions can be operated by the operator manually in the operation of the operator workstation interface in the UPFC control protection system:

The conversion between AC voltage control and reactive power control, which is completed by the sequence function under the operation and the conversion would not cause any disturbance of the operating system.

The conversion between multiloop coordination power control and single-loop circuit power control, which is completed under the operation through the sequence function, and the conversion would not cause any disturbance of the operating system.

Under normal operation, the serial and shunt converters are put into operation and connected to each other on the DC side. The shunt converter controls the AC bus voltage or reactive power exchange and the DC voltage, while the series converter controls the line power flow. In order to improve the reliability of the system, system operational modes can be switched. Specifically, different operational modes can be switched in different fault areas.

The UPFC system can be divided into the outer protection zone and the inner protection zone, as shown in Fig. 4.24.

When an external fault occurs, the UPFC can run continuously. If the current of the series converter exceeds the current tolerance ability during the fault period, the series converter will be temporarily out of service, and it will be recovered after fault clearing. If the series converter is located on a line removed due to a permanent fault, the series converter will not be switched on again. If an internal fault occurs, the UPFC will stop functioning, and it will restart under a different mode according to the fault type.

6.4.1 Controller Related Data Points

The creation of the database for the operations workstations requires combining all of the database information for all of the PPCs in the SOW database. Procedures described in the previous section explained how data points from spreadsheets can be transferred into new spreadsheets for the SOWs. This new spreadsheet, in the form of a CSV file, is populated with all of the data points from the various PPC application spreadsheets. The standard method of Copy and Paste can be used to quickly build the new spreadsheets which include all points for all PPCs.

As described for the PPC database development, the programmer must first create one of each data type in the SOW application software. The operator workstation software, such as Wonderware InTouch, includes an application in which the database can be created. For the SOW, there are typically three basic data types, representing the different types of data being handled:

I/O Discrete – input and output discrete points

I/O Integer – input and output analog points, typically 32-bit double integers

I/O Real – input and output analog points, 32-bit floating point

By entering one of each of these data types with tagname and description, an initial database can be created which establishes the format for all entries. As described for the PPC software, this initial database can be exported into a CSV file, which can then be manipulated in Excel. All of the required fields are represented by headings, so the programmer can identify what additional information must be entered for each point.

One key difference between the SOW database and the PPC database is that the SOW database requires a reference to the specific PPC or controller, as the I/O communication driver needs to know how to access each point from each controller. For example, consider a discrete input signal from the Low Lift PPC: LLF_RWP2_00_SRN, which represents the run status of raw water pump 2 in the low lift PPC. In addition to the data type, tagname and description for this point, the SOW database also requires a reference or Node Name for the PPC from which the data is derived. The Wonderware InTouch software uses the term ‘Access Name’ to refer to the specific PPC.

Using the water treatment plant example, there might be five controllers whose first tagname fragments would appear as follows:

LLF  Low Lift or Raw Water Station

PRE  Pretreatment

FLT  Filtration

HLF  High Lift or Treated Water Station

CHM  Chemical Injection Systems

Using examples from the Wonderware InTouch SCADA software package, a partial database has been created with discrete and analog points. For clarity, some of the fields in the InTouch database entries have been omitted, such as initial value, whether the point is retentive, and the alarm or event nature of the point. The information shown represents the key information for each point.

Figure 6.23 illustrates a sample database export with some of the discrete points entered through the SOW software. This illustration is based upon the Wonderware InTouch software. In these examples, the Access Name if the PPC node, ‘RPS’ for Remote Pumping Station.

Figure 6.24 illustrates a similar export for analog points. These points include a range for both the raw input value and the scaled engineering value. Typically the scaling of analog values is performed in the PPC application program, but this feature allows the scaling to be done within the SOW database. Again the Access Name provides the link to the I/O server program.

The ‘Item Name’ is the reference to the specific database point in the controller, while the ‘Access Name’ identifies the controller; both fields use alphanumeric names. Note in both illustrations that the Item Name is the same as the Tagname; the tagging system within the ControlLogix controller allows the SOW database to reference each point by the tagname, making the database references straightforward.

Management Level

The top level of an HVAC control system is the management level consisting of personal computers or multiple PCs connected via an Ethernet network. These operator workstations can communicate with, interrogate and control any of the controllers and devices on the network. The management level provides many functions:

Administration and control of the HVAC system

Programming for the system and other controllers, including operation sequences

Display of system information

System reports

System scheduling

Archive and analysis of historical data

Backup of controller databases

Alarm reporting and analysis

Trend analysis

The HVAC system is usually managed by a server and operator workstation using standard operating systems, specific HVAC software applications, GUI interfaces, and web access. The HVAC control system may be interfaced or integrated with fire alarm, video surveillance, access control, and lighting control systems. The HVAC system is also a significant part of a facility management and maintenance management system, primarily for tracking, managing, and optimizing energy use.

16.18.2 The frame applications

A DTM is displayed or accessed from a frame application, which is a software window that provides the user interface between the device DTM and various applications such as device configuration tools, engineering work stations, operator consoles, or asset management tools. The frame application initializes the DTMs and connects it to the correct communication gateways. A single FDT frame application supports more than 15 of the world’s most popular field communication protocols including HART, PROFIBUS, FOUNDATION Fieldbus, Modbus, DeviceNet, Interbus, AS-Interface, PROFINET, IO-Link, CC-Link, and more. FDT supports a mixture of any number of networks and further enables communications to tunnel through any number of networks to reach the end device.

12.1 Overview of Project

The water pumping station application program involves the operation of and the control for two pumps, which involves both Manual and Automatic modes of control, and the collection of data for use at the operator workstation. The programming is based upon the Allen-Bradley ControlLogix PLC [Programmable Logic Controller], as this PLC is a well-established controller in the field of automation systems. The A-B ControlLogix PLC serves as a good example for demonstrating structured programming techniques.

This chapter illustrates the application of all of the principles described in the book, guidelines and methods described in this book, to create a real-world application program for a known PLC. As will be seen in this chapter, each of the steps outlined in Chapter 3 will be shown as applied to this project.

Key Points

•

The C/E/I commissioning engineer will be very familiar with and involved in the development of the instrument loop testing scheme, schedule to witness all final loop tests, field instrument to operator workstation

Develop suitable paperwork to document and schedule the witness of all motor checks

Develop, with system commissioning engineer, procedures to test interlocks, emergency shut-down systems and control system software control sequences

The C/E/I commissioning engineer will also set up sanity checks to ensure existing equipment to be utilized in a newly commissioned facility is fully operational prior to handover to the project team

Ensure that all labeling of cables, panels and junction boxes is adequate and meets all specification.