FIELD OF INVENTION
The present invention relates to a system and a method for monitoring the selected real time data in a power plant at remote locations in the plant without running cables from the control room or without any Line Of Sight (LOS) issues. More particularly, the invention reates to a Remote Performance Data Monitoring (RPDM) System adaptable in large power plants, and a method for remotely monitoring real time data. BACKGROUND OF INVENTION
According to the prior art, in a Distributed Control System (DCS), the Input/Output modules and the controllers in the central control room process the data captured from various sensors, actuators, and field devices in the manufacturing plants for example, a power plant. The data is centrally stored in the control room and this data is processed by the controller and used for controlling, monitoring and decision-making on the process implementation. An engineer working in the field doesn't have real time data readily available with him. He communicates with other technicians/engineers in the control room for knowing the status and values of the process parameters while working in the field via walkie-talkie. This is a cumbersome and slow process and needs more manpower for assisting the field technicians.

A typical Distributed Control System as shown in Figure-1, has mainly the following components:-
1. Field sensors, transmitters, actuators etc;
2. Input/Output module connected to the field elements for data acquisition;
3. A controller unit for processing the acquired data and also for issuing the
commands for field operation,
4. An HMI system for data display and control;
5. A Historian for data storage; and
6. Plant Network, which interconnects all the controllers and HMI are
interconnected.
The Input/Output modules are connected to the field elements, and the data provided by the field elements is acquired by the Input module and the command issued through the controller is sent to the output field elements through the Output module. The controller is provided with suitable logic to process the data, and output signals representing monitoring and control instructions so as to implement the desired functioning schedule of the plant . The controller processes the data available in the Input module and take decisions based on the logic built in the controller. If the decision is to output some values to a field device, then this is sent out through the Output module.

Some of the prior art systems use wireless field devices to collect data and display. Such systems although display real time data but the usage in limited wireless coverage area. These systems thus cannot be used to make the real time data displayable over a wide area. Many other prior art systems need Line of site requirements for display of real time acquired data.
Some known MIS systems use dialup connection for connecting to HMI. This method requires the availability of ,3 direct telephone connection.
The existing systems using GPRS, collect data in a file and transmit this to a remote system at a predefined interval. Such known systems are not capable to transmit the real time data on a continuous basis due to periodical break in the communication, because of the low bandwidth of GPRS system.
OBJECTS OF INVENTION
It is therefore an object of the invention to propose a Remote performance data monitoring system (RPDM) adaptable to large power plants for remote monitoring of real time plant data.

Another object of the invention is to propose a Remote performance data monitoring system (RPDM) adaptable in large power plants for remote monitoring of real time plant data, which is capable of making available atleast selected real time plant data for remotely monitoring the plant operations from anywhere in the globe.
A further object of the invention is to propose a Remote performance data monitoring system (RPDM) adaptable in large manufacturing plants for remote monitoring of real time plant data , which eliminates the requirement of any physical connectivity or Line of Sight (LOS) requirement between the plant and the RPDM-system.
A still further object of the invention is to propose a Remote performance data monitoring system (RPDM) adaptable in large power plants for remote monitoring of real time plant data, which eliminates disposition of repeaters between the plant and the RPDM-System.

A still another object of the invention is to propose a Remote performance data monitoring system (RPDM) adaptable in large manufacturing plants for remote monitoring of real time plant data, which transmits the real time data from the RPDM-location to a remote terminal using General Packet Radio Service (GPRS), EDGE and evolving 3rd Generation 13G).
SUMMARY OF INVENTION
According to the invention, the Remote Performance Data Monitoring (RPDM) system, helps site engineers to view the real-time data anywhere in the power plant for example, power plant field with the help of a Tablet PC/Laptop without running any wires to field or having any physical connectivity to telephone lines or other means of communication devices. The new system doesn't require any Line of site (LOS) or repeater to communicate between the central control room and the remote terminal. The real time data captured at the central control room will be transmitted to the remote tablet PC using the General Packet Radio Service (GPRS), EDGE and evolving 3rd Generation (3G).

The RPDM-System enables the field engineers to view the real time status of the parametric data representing the process features, while working on the field, thereby improve the productivity and communication time and quality . The system allows the field engineers to fine tune the control elements more accurately and fast.
According to the present invention, the system is designed to enable sizing and packeting the data in such a way that the system attains the capability of continuous communication without interruption. In case, the communication is disconnected due to external factors, it gets automatically and transparently reconnected without user intervention.
The RPDM- system is developed to make the real time data acquired in the central control room of a power plant, available to the field or anywhere else in the world without physically connecting the wires. The system is developed with features such as trend, predictive intelligence, watch window, critical window, highlighter, LED indications for the connectivity etc. The system will help the field engineer to view the real time status and values of the plant/process data while working on the field and helps to tune, troubleshoot, and maintain the system more effectively and efficiently thereby improve the productivity and communication quality. The RPDM system improves the productivity and facilitates fast and accurate response by the user.

The RPDM system uses GPRS/EDGE connectivity and establishes a secured connection through Open Virtual Private Network(VPN) with SSH (Secure Shell) and L2TP (Layer 2 Tunneling Protocol), allowing only authorized persons to view the data. This method provide*; more flexibility and freedom for the field engineers.
The RPDM is developed as a future proof system enabling it to work with 3G (Third generation) and the evolving 4G systems without major software modifications.
Accordingly, there is provided A Remote Performance Data Monitoring (RPDM) System adaptable in large power plants for remote monitoring of real time plant data, comprising a Distributed Control System (DCS) having a plurality of Human Machine Interface (HMI) devices, one of the HMI devices being assigned for data acquisition; a data Servel for acquiring selected real time data from the HMI device and transmitting the configured signals representing said selected real time data to any of the plurality of remote terminals in the plant or anywhere having authorization ke/ and accessing the data provider; a standard secured gateway capable of establishing a secured connection between the data

provider, remote terminals , and the gateway so as to allow exchange of data
using the secured channel by using Layer 2 Tunneling Protocol (L2TP) supporting
an open virtual Private Network (open VPN) and the internet; encrypted key
generated and loaded in the gateway to identify and secure the data provider;
and access keys for the open VPN clients generated at the gateway with
passwords for authentication.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1- shows a typical DCS-system in a control room of a manufacturing plant.
Figure 2- Schematic representation of the Remote performance data monitoring
system (RPDM) according to the indention.
Figure 3- shows a flow-chart of the RPDM-system according to the invention.
Figure 4- shows a sample screen of the RPDM-system (client) according to the
system.
Detail description of the invention
The RPDM system as shown in Fig. 2, basically uses the existing Distributed Control System (DCS) in which one of the existing Human Machine Interface (HMI) devices in the control room is assigned for data acquisition. The system works in a data provider- data subscriber manner. The required signals need to be configured in a data Server. The real time data available in the HMI (1) is acquired for the selected signals and made available to any RPDM client that

has an authorization key. The Server waits indefinitely for a new client connection. The communication between the data receiver (4) and the data provider (2) takes place through a standard secured gateway (3). The gateway (3) works on Secure shell (SSHT, that allows data to be exchanged using a secure channel between the networks, and uses the Layer 2 Tunneling Protocol (L2TP) to support Open Virtual Private Network (Open VPN). A secured connection is established between the Server (data provider), the gateway (3) and the data receiver (4). 128bit encrypted key is generated and loaded in the gateway (3) to identify and secure the Server. Access keys for the Open VPN clients are generated at the gateway (3) with password for authentication. Only those data receivers (4) that have the access keys and password can connect to the Server. Thus, the gateway (3) takes care of the security, tunneling etc. System security is established with the firewall settings and password options.
When a new RPDM client tries to connect the Server, it passes through the secured gateway (3) and initiates, a dialog with the data-provider . The data provider accepts the connection and initiates a new session for the communication and returns back to the waiting state, to accept new connections.

Figure 3, shows the steps to be performed by the RPDM-system while remotely monitoring the data which data mainly consists of two parts:
1. Static data, that won't change frequently and
2. The dynamic data, that changes with respect to time.
The static data consists of the description and engineering unit of the signal and the dynamic data holds the status or floating point values with the data quality attribute. To reduce the continous load on the network, the static data is transmitted only during the warming up phase. The server (2) transmits the dynamic data at 1 second interval and it will be updated on the client receiver (4) as and when the data packet is received. If it is observed that few data packets are missed/corrupted durirg the transit, the last value will be displayed on the screen during the said period.
Special features of the RPDM-System:
1. The connectivity with the RPDM server (2), the arrival of good data packet and receipt of bad data packets are indicated with soft LEDs on the RPDM client screen (Fig. 4).

2. The data is displayed in a tabular form with indication of signal quality. A
small trend window with provision to configure two signals is part of the
main screen and an additional slightly bigger trend with provision to
configure another two signals is made available.
3. A watch window with a provision to select any five signals from the main
list to form a group display for a closer observation is possible.
4. A critical signal window with a provision to display atleast ten important
plant parameters is also available (as shown in figure 4).
5. Predictive Intelligence for a linear varying signal indicates the probable
date and time at which the signal reaches the configured alarm limits.
Audio alarm is initated when the set alarm limit is reached with a facility
to acknowledge the alarm.
6. The Highlighter feature can be used for highlighting any signal in the list.
The selected signal will be shown in bold letters with blue color for easy
identification. It is also possible to remove highlighting.
Thus, the system of the invention enables data monitoring at remote locations of any power plant.

We Claim:
1. A Remote Performance data Monitoring (RPDM) System adaptable in large power plants for remote monitoring of real time plant data, comprising:
- a Distributed Control System (DCS) having a plurality of Human
Machine Interface (HMI) devices, one of the HMI devices (1) being
assigned for data acquisition;
- a data provider in the form of a Server for acquiring selected real
time data from the HMI device (1) and transmitting the configured
signals representing said selected real time data to any of the
plurality of remote terminals (4) in the plant having authorization
key and accessing the data provider;
- a standard secured gateway (3) capable of establishing a secured
connection between the data provider (2), remote terminals (4),
and the gateway (2) so as to allow exchange of data using the
secured channel bv using Layer 2 Tunneling Protocol (L2TP)
supporting an open virtual Private Network (open VPN) and the
internet;

- encrypted key geneiated and loaded in the gateway (3) to identify
and secure the data provider; and
- access keys for the open VPN clients generated at the gateway (3)
with passwords for authentication.

2. The system as claimed in claim 1, wherein the data to be acquired and
transmitted comprises static data and dynamic data.
3. The system as claimed in claim 1 or 2, wherein the static data is
substantially unalterable and comprises signals representing description
and unit of the engineering parameters, and wherein the dynamic data
altering with respect of time, and comprises the features of status or
Moating point values with the data quality attribute.
4. The system as claimed in any of the preceding claims, wherein the static
data and the dynamic data is respectively transmitted during the warming
up phase and at one (1) second internal which balances the load on the
network.

5. The system as claimed in claim 1, wherein indicators are provided on the
RPDM-client Screen (PC) n the form of soft LEDs to visually confirm
suitable connectivity of the RPDM Server, arrival of good or bad data
packets.
6. The system as claimed in any of the preceding claims, wherein the main
screen is provided with trend window feature so as to allow configuration
of additional number of signals with bigger trend.
7. The system as claimed in claim 1 or 7, comprising a watch window with a
provision to select and display a group of signals for closer observation.
8. The system as claimed in claim 1 or 8, comprising a critical signal window.
9. The system as claimed in any of the preceding claims, comprising
predictive intelligence feature.
10. A Remote Performance Data Monitoring (RPDM) System adaptable in
large power plants for renote monitoring of real time plant data, as
substantially described and illustrated herein with reference to the
accompanying drawings.

The invention relates to a Remote Performance Data Monitoring (RPDM) System adaptable in large power plants for remote monitoring of real time plant data, comprising a Distributed Control System (DCS) having a plurality of Human Machine Interface (HMI) devices, the of the HMI devices (1) being assigned for data acquisition; a data provider in the form of a Server for acquiring selected real time data from the HMI device (1) and transmitting the configured signals representing said selected real time data to any of the plurality of remote terminals (4) in the plant having authorization key and accessing the data provider; a standard secured gateway (3) capable of establishing a secured connection between the data provider (2), remote terminals (4), and the gateway (3) so as to allow exchange of data using the secured channel by using Layer 2 Tunneling Protocol (L2TP] supporting an open virtual Private Network (open VPN) and the internet;encrypted key generated and loaded in the gateway (3) to identify and secure the data provider; and access keys for the open VPN clients generated at the gateway (3) with passwords for authentication.