Description:
The application consists of a hot water circuit, a cold water circuit and an exchanger that transfers the heat between both circuits. In the cold water circuit, a variable speed pump impels the water from the supply tank to an upper tank equipped with a valve at the top to make level control experiments with and without overpressure. Besides, the pressure and flow rate can be controlled in this circuit and the regulation can be carried out through the variable speed pump or through a pneumatic valve.
In the hot water circuit, a pump makes water flow through a heating device and the heat exchanger. The heating device can be used as an actuator for temperature control. In addition, the temperature of this circuit can also be regulated by controlling the flow that circulates through the cold water circuit. The application includes several manual valves with scale to introduce disturbances to the system. Devices for direct visualization of all the process variables are also included. The controller included in this application allows for the regulation of the system variables independently (Flow, Level, Temperature and Pressure) or by Cascade Control (Flow-Level and Flow-Temperature). The controller can be configured through its own screen or through the control and acquisition software included
Hot Water Pumping Unit :
- Water pumping unit designed for temperature control applications.
- The elements included in the module are :- Circulation Pump : Supply Voltage : 230 VAC Single-Phase.
- Nominal Power : 103 W; Nominal Flow : 10-63.2 Ltr./min. Max. Operating Pressure : 10 bar.
- Ball Valve with Scale : Metering Ball Valve. Scale from 90° (closed) to 0° (open).
Large Hydraulic Supply Unit:
- Module designed to pump water to the other devices of the application. It is recommended for multivariable control applications. The elements included in the module are :-
- Reservoir Tank : Capacity – 100 Ltrs. Safety low level switch, Refrigeration circuit, Temperature Gauge. Centrifugal Pump : Supply Voltage : 230 VAC three-phase. Nominal Power : 1.1 kW. Nominal Flow : 100 l/min.
Power Supply Module:
- Provided for Control Circuits Module, Supply voltage (single-phase) : 230 VAC, L+N+G. Removable ON/OFF key switch.
Electromagnetic Flow Sensor: Provided for High Levels.
- Magnetic-Inductive Flow Sensor : Supply Voltage : 18 – 30 VDC. Flow Range : 0 – 100 l/min,
- Accuracy : ± 0.8 % of measured value + 0.5 l/min. Repeatability : ± 0.2 l/min. Response Time : 0.15 sec.
Pneumatic Control Valve for :
- Pneumatic Control Valve : Normally closed valve. Linear plug. Electro-pneumatic
- Hydraulic Circuits linear positioner.
- Control Signals : 3 – 15 psi, Actuator : Diaphragm type. DN 20. Flow : Cv: 6.6 (referenced to USGPM and psi units) Kv: 5.7 (referenced to m3/h and bar units) Pressurized air inlet required : 2.5 bar.
Manometers: 2 Nos.,
- Pressure Range : 0 – 10 bar. Manual ball valve. N-ATC01: Air Filter and Pressure Regulator with Manometer Module.
- Air pressure inlet admitted range: 0 – 12 bar. Output pressure: 2.5 bar. Drain capacity: 12 cm3
Heating Module:
- Rating : 6 – 2 kW
- Heating Resistance : Supply voltage (single-phase) 220 VAC.
- Maximum power: 2 kW. Safety temperature switch.
- Safety temperature sensor : Transducer type: thermocouple type “J”.
- Temperature range: -100 – 900 °C.
- Accuracy: ± 1 °C. Safety low level switch.
- Safety relief valve : Pressure setting : 3 bar. Discharge line.
Additional manual opening system Manometer: Pressure range: 0 – 4 bar. Automatic air vent valve. Control module box. 2 kW power control driver. Based on Solid State Relay (SSR). 24 VDC Digital input. Safety Temperature Controller: ¡ ON/OFF control. ¡ Set temperature: 65 °C. Safety stop input for low level switch.
- Variable-Frequency Driver: Module to control the turning speed of the pump. The elements included in the module are :-
- Variable-Frequency Drive : Maximum Power: 1.5 kW, Input Control Signal : 4 – 20 mA. Safety stop signal connector. Local / remote control selector. Start / stop selector
Large Pressurized Transparent Tank :
- Pressurized transparent tank with graduated scale for level and pressure applications. The elements included in the module are :-
- Pressurized Tank : Max. Pressure : 4 bar, Height : 750 mm. Diameter : 140 mm.
- Volume : 11.5 Ltrs.
- Height with millimeter scale: 550 mm. Polycarbonate protective cover. Safety relief valve: Pressure Setting : 2 bar. Discharge line. 3 Manual ball valves. 2. Ball Valve with Scale. Metering ball valve. Scale from 90° (closed) to 0° (open). Capacitive Level Sensor for High Levels. ¡ Supply voltage: 24 VDC. ¡ Level range: 0 – 700 mm. ¡ Output current: 4 – 20 mA. ¡ Probe material: PTFE. Compressed Air Pressure Sensor for High Levels. ¡ Supply voltage: 24 VDC. Pressure Range : 0 – 6 bar. Output Voltage : 0 – 10 V.
Water-Water Heat Exchanger: The elements included in the module are :-
- Heat Exchanger : Type : Plate Heat Exchanger. 2 Manual ball valves. 2 Analog flow meter : Flow range: 0 – 2 l/min. 4. J Type” thermocouple.
- Transducer type: thermocouple type “J”.
- Temperature Range : -100 – 900 °C, Accuracy: ± 1 °C.
- 4 Temperature Analogs : Temperature Range : 0 – 120 °C. ¡ Accuracy: ± 1 °C.
Industrial Controller: USB Communication. Display: full-color LCD 9 cm (3.5 inches) with built-in backlight.
Configurable sample rate chart (1 second to 5 minutes). Control parameters: Control type: ON/OFF control. P, PI, PID control. P, PI, PID control with gain scheduling (up to 3 set of PID parameters). Predictive control (dead-time compensation). Adaptive control. P, PI and PID with feedforward. Cascade control. Cascade control with feedforward. Ratio controller. Ratio station. Control output type: Analog output. Time proportioning output. ON/OFF output. Motorized valve with feedback. Motorized valve without feedback. Split output with combinations of relay, digital output and current outputs. Autotune function: On – demand calculation of control settings. Set points: Configurable through the front panel or the computer. Up to four local set points, all selectable via digital inputs or front panel. 8 Blocks math functions. 8 Blocks of logic functions. 2 Blocks of totalizer functions. 8 Blocks process alarms. 4 Analog inputs with 125 ms of sample rate. 2 Analog outputs. 4 Relays. 6 Digital I/O
Acquisition, Control and Controllers: The main functions of this software, based on LabVIEW, are :-
- Configuration Software The following process variables can be visualize and managed via software :-–
- Set Point (SP) of first and second control loop output process (O/P) of the first and second control loop process variable (PV) of the first and second control loop.
- Data visualization, data management and data storage of all process variables involved in the control loops.
- The following process parameters can be adjustable via software :- ON/OFF controller parameters
- PID controller parameters of one control loop or two control loops, set point values, bias and slope ratio and Feedforward gain.
- 12-Four-Channel Signal Recorder Module – Communication : USB. Ethernet.
- Display : Full-color LCD 9 cm (3.5 in) with built-in backlight. 4 Analog inputs with
- 125 ms of sample rate. 2 Analog outputs. 4 Relays. 2 Digital Inputs. 1 Digital Output.
Large Pneumatic Supply Unit: Module designed to supply compressed air to the rest of devices of the application.
- The elements included in the module are :– Air Compressor: 8 bar approx.
Some Practical Possibilities of Application : Design and assembly of the control system :–
- Familiarization with the main components of a control system: sensor, actuator & controller.
- Preparation of the piping and instrumentation diagram (P&ID) of flow, level, pressure and temperature control systems.
- Preparation of circuits, wiring, terminals and connections diagrams of flow, level, pressure and temperature control systems.
- Assembly of the hydraulic circuit of different control systems.
- Wiring of the control and measurement signals and the power supply of different control systems.
- Disturbance compensation through feedforward control. Analysis of the system and design of control strategies :–
- Characterization of different control systems.
- Manual control of the system with an industrial controller (open loop).
- Effect of the parameters of a PID controller.
- ON/OFF control of a temperature control system.
- PID control of a flow control system.
- PID control of a level control system.
- PID control of a pressure control system.
- PID control of a temperature control system with different actuators (heating element, variable speed pump, pneumatic valve).
- Cascade control of level and flow.
- Cascade control of temperature and flow.
- Response of the controlled system to disturbances and changes of the reference signal.
