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| Die Casting Controllers for HMT, India |
The Die casting machine with the SPA Controller has the following advantages -
- Easy replacement of Solenoids of different Current / Voltage ratings.
- Very rugged constructional features ensure proper functioning of controls at extreme working conditions.
- Proper interlocks for each machine operation ensure safety and speedy operation.
There are many selections to be made depending on the features of the machine. All the selections are understood by the Controller as its Digital inputs. The Digital inputs carry the information of all the selections made and also the status of each unit in the machine. The timeout of all the hardware timers are also sensed by the Digital inputs on the Controller. All Limit Switches, Pressure and Float Switches are also understood by the Controller as its Digital inputs.
All the operations of the machine that are controlled by the operations of the Solenoids and Contactors are in turn operated by the Controller and are understood as the Digital Outputs. The Controller Switches On / Off this equipment by energizing its Digital Outputs corresponding to each Solenoid / Contactor.
The total system facilities include -
- 50 user configurable Display Pages
- 25 nos. of Catalogue Data in Memory with Password Protection for downloading to Controller and Modifying
- Manual, Semi-auto and Auto Mode of Operations
- Hardware lock for proper safety of Operations
- Four levels of password for Entering / Modification of Parameters and Catalogue Data
- User configurable Alarm Messages and other Information
- Latest occurred 200 Alarms with their Date and Time of occurrence stored in memory
- Hot keys for quick viewing of required Display Pages
- Screen information printing
- Printing facilities of Alarm and Catalogue Data
- Additional EPROM and EEPROM for Program Backup
- Built-in PID controls for closed loop control applications (Tuning also possible from Operator Station)
The fast execution time of 2 microseconds / 1K of program and fast updating of I/O channel ensures fast scanning of field I/O. The Controller can be Programmed by using Ladder Logic combined with powerful Function Block Elements. The I/O provide easy connectivity to Linear Encoders, Thermocouples, Proportionate Control Valves, Variable speed and Pressure Transducers and a variety of Limit Switches, Proximity Switches and Solenoid Valves.
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| Control System for Tower Testing for Jyoti Structures, India |
This Control system involving the "SPAMICRO" range of PLCs and the SPAVISOR-400 SCADA (Running on a PC) was supplied to M/s Jyoti Structures Ltd. for their R&D Division. The system is implemented to Monitor and Control the load exerted on the tower being tested.
The application Monitors and Controls various load set points applied on a tower in all directions (i.e. Transverse, Vertical and Longitudinal). Here feedback is got from load cells and depending on the Feedback, the system Controls the Motors / Winches, to exert more loads, or to reduce the load, which has already been exerted.
The Set-points are assigned by operator, in the form of a recipe which the Operator can use as a set of instruction steps to the PLC to perform all the tests required to approve the tower under test. The various Trips and Alarms associated with the Motors and Safety Circuits are processed by the PLC and necessary Control Actions are initiated. The Control Philosophy has been implemented in such a fashion that if a trip occurs, the Alarm is generated on the PC and the power to the particular Winch / Motor is switched off. Emergency Stop is implemented for safety. This facility has been implemented in two ways, either the Process can be stopped in Auto Mode by clicking the Emergency Stop Button on the PC or by Pressing a Push Button on the Control Panel.
The SCADA running on the PC is Developed on the QNX Real-time OS for monitoring and recording of the process parameters. Maximum Set Points can be written out in text or ASCII format, on any DOS/Windows based editor and can be downloaded to the PLC via the SCADA. Once the parameters have been set, the user can begin the process from the SCADA,, simply by instructing the PLC to load the tower to a weight. Typing in the load value as an actual load or as a percentage can do this. Once this is done, a Mimic of the application appears on the screen with Real-time field values displayed in the form of a graphic trend, which gives the user an exact feedback for his control operations. A Fuzzy logic based pop-up on screen guides the user through the various steps to do a successful test avoiding any dangerous operations which may jeopardize the whole test setup.
One of the advanced features of this package include comprehensive report generation and trending. Reports of the tests can be generated in terms of shifts, alarm with date and time of occurrence and so on. Graphical trends of the process with respect to time can be plotted. These may be archived on the PC for future reference. |
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| Cold Strip Mill at Vizag Steel Plant, India |
The Primary Automation System includes two zones; each has a separate RTP Controller, with 600 I/O points. Redundant Target Node Controllers (RTP 2200) with four I/O chassis and 40 I/O cards are used in the Instrument Control Station. Considering the critical nature of incinerator control, the RTP 2200 also contains redundant I/O cards. The Electrical Control Station, which operates as a Secondary Control Station, performs the interlocking and Start / Stop functions for Motors and Pumps. A single Target Node Controller (RTP 2000) is configured, with two I/O chassis containing more than 20 I/O cards.
The Instrument Control Station is located in the former lab facility and the Electrical Control Station is located at, what was once, the Electrical Room. The distance between the Instrument Control and the Electrical Control Stations is more than 300 meters. Each of the Control Stations is located more than 300 meters away from operator room. Fiber optic cables are used to connect the whole System. Three Citect Operator Stations are used for both the Instrument and Electrical Control Stations. Two of the Operator Stations are set up to function as the Primary and Secondary Servers. The third Operator Station is set up as a Client. Another MIS (Manufacturing Information System) computer to Monitor the Plant Process, and a QA (Quality Assurance) Station for Remote Monitoring of product quality, are also connected to the Citect network. A 20mA Current Loop Interface (Siemens 3964R protocol) is used by the Oven Control System to communicate with the L2 Siemens R30K computer system at the Cold Strip Department. These systems exchange information such as Machine Speed, Coil Number, Steel Depth / Width and Oven / Steel Temperatures.
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| Power Plant Automation at Bellary, India |
The Power Plant Control System is using three redundant RTP 2200 Hybrid Control Systems. Dual controllers are used for redundancy, and in case of failure; the standby controller will bumplessly take over, without affecting the normal system operation. In order to control two boilers and one turbine, each RTP 2200 controller has five racks of I/O.
Citect software based on Client/Server architecture is used for operation. Two I/O servers are configured to provide redundancy for alarming, trending and reporting. A 10 MHz Ethernet network is used for communication between RTP 2200 controllers and Citect Operator stations. A DAS (Data Acquisition System) is used to retrieve temperature values and forward them to the I/O server via Modbus protocol over an RS-232 serial port. Twelve Operator stations are configured in the system. By optimization of system resources, the update of system operator displays has reached 500 milliseconds. One engineering station is available to implement on-line configuration and system maintenance functions.
System I/O Configuration
- Analog Input Cards 78
- Analog Output Cards 6
- Thermocouple Cards 3
- Digital Input Cards 36
- Digital Output Cards 45
- Pulse Input Cards 2
- RTP 2200 I/O Points 1678
- DAS System I/O Points 360
- Total I/O Points 2038
System Control functions
- Combustion Air System
- Feed Water Control System
- Boiler Water Circulation System
- Furnace Draft System
- Main Steam and Reheat Steam Temperature Control
Combustion Fuels Control
- Total Head Main Steam Pressure Control of Six Boilers
- DEH Control of Three Turbines
RTP 2200 HCS controller is based on the Intel 586 microprocessor, which provides four to ten times faster, scan rates than a normal DCS and PLC solution can provide. Configured with sixty PID loops and three thousand floating point calculations the system runs at 50 passes per second. The HCS controller completes all I/O scans, Boolean logic algorithms, analog calculations, peer to peer, and operator station communications in less than 20 milliseconds.
Three RTP 2200 controllers are configured in the system. High speed Ethernet and peer-to-peer communications are used to exchange process data. In the mode of peer-to-peer communication, the peer variable values are only transmitted if a delta exists, (a change of state for digital values, or a change greater than the defined deadband for analog values). This optimization technique increases the overall communication efficiency of the entire system. Peer-to-peer communications does not rely on an additional software package. Configuration is simple, only requiring a global data peer variable definition. It is peer-to-peer communications that makes it possible to control the total head main steam pressure of the six boilers.
The Power Plant control system is configured with interlocks to safely control start-up and shutdown of the six 220 ton boilers and the three 100 MW turbines. To trace and analyze failures, the RTP 2200 Hybrid Control Systems are configured with SOE (Sequence of Events) capability, providing one millisecond resolution. When status of an SOE digital input changes, an interrupt is sent to the RTP 2200 controller. The input and its time-stamp is recorded in a buffer by the controller. Citect SCADA (Supervisory Control and Data Acquisition) software retrieves and records all SOE information for analysis. The main I/O server controls time synchronization. When the difference of any controller time is greater than a predefined limit, the main I/O server will send a clock signal to three RTP 2200 controllers to synchronize their clocks. This synchronization technique guarantees high resolution of time for the three controllers and increases the resolution of time stamping for SOE processing. |
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| Panel Line Automation for Videocon Narmada Glass, India |
Videocon Narmada Glass is one of the major manufacturers of Panel and Funnel glass for the TV Picture Tube in India. Having the largest market share, in India, the factory caters to almost all the picture tube manufacturers and supports most TVs manufactured in India. They have one Panel and one Funnel line, where we have used the RTP Control system, to manage and control their gauging operation.
The complete automation of the gauging operation of the panel line was taken care of by the RTP6800 controller that SPA setup for Videocon. The control system starts its control operation once the molten glass has been poured into the molds on the panel line. The Panel line has a capacity to produce 9 panels every minute, so, once production begins for the day every minute the RTP control system needs to count, measure, analyze and accept/reject 9 panels. This required a system with very high speed I/O access, and analysis capability, which was ideally found in the RTP Control System with QNX embedded in it.
After cooling of the mold, the panels are placed on a conveyer and the conveyer transports these panels through a special annealing process to the point where the panel is checked for stud plane contour and periphery out-of-flat, which are terms for the various measures and checks that need to be performed to ensure that the TV Panel is suitable for shipment. These checks ensure that the Panel is not skewed or deformed, making it unsuitable for making a picture tube. Milling and other correction operations may modify mild deviations. There are a total of 78 probes for checking the various parameters of the panel, All signals from the probes are signal conditioned and read in directly to the RTP Control System.
These signals are then compared with pre-set values, fixed at the start of each production cycle, and accordingly the panels are marked in terms of quality. These marked panels are then conveyed to the warehouse for shipment if they are acceptable. The panels with mild deformities, are marked as such, and conveyed to the lathe chop for correction. The panels that are not acceptable are moved to the warehouse for recycling.
The RTP System consists of the following components -
- Embedded QNX Controller
- 16 Digital Outputs
- 48 Digital Inputs
- 96 Analog Inputs
The Embedded QNX Controller consists of an Intel Pentium Processor with built-in Ethernet support and serial ports, which may be used for VT100 and VT 320 terminal emulation. The data control is done through the VT 320 connected through the serial port. Online display, calibration settings and error messages are displayed on the VT terminal itself. Data Logging is done on a high-end VAX system provided by Compaq. The RTP system is configured such that it sends all data to the VAX system over TCP/IP protocol on Ethernet. All user level reports are prepared on the VAX System with the data that the RTP System sends out to it.
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