Electrical Power can be used for most anything. It also can be stored and used later using Batteries. Alternative Energy Solutions like Solar, Wind and Tidal are providing new sources of Energy.
Fossil Fuels are running out and we have to become more energy efficient. Notebooks and Tablets are fast replacing desktop computers. Network servers and Cloud Solutions still use more power than needed. We have to use power for Productive and Creative activities.
Wastage of too much power leaves a mark, a carbon footprint, we also should shift to the low safe voltage standard of 24V. This will make conversion and distribution safe and solar energy friendly.
Learning electronics in theory by studying books is the conventional way, this method may help in History and Maths. Maths needs a paper and pencil for practicals and history needs a well equipped Library. In these modern times, the web has made access to wide range of learning information easy, which is true Knowledge Empowerment. The greatest gift a Child can get from the Parents or School, is Knowledge.
Process Control Instruments - These are some instruments i manufactured when i used to run my own industrial automation business.
Now many Virtual Electronics Workbench Software and Interactive Tutors are available, these aid learning. We have to design, build and apply some electronic ideas in 3D Hardware, for complimenting the Book, Academic or Web learning.
Practical and Theoretical study in electronics has to be in Tandem, this is possible only when Industry works with Universities to create real talent and skills in students. The applied technology is evolving, hence the academic education must be relevant when the student gets into his first job.
A closed loop controller is the heart of an Industrial Automation System. Right from an On-Off Hysteresis Controller to a Auto Tune PID Controller, we find solutions of different complexities. Each solution might suit a particular system; depending on the requirements of Ease-of-use, Cost and Process Type.
A PC based multiplexed scanner controller with data-acquisition cards and I/O Cards can be solution for Laboratory or Research. This is used when real time control is not required or where the control failure will not lead to damage or loss.
A PLC or Microcontroller based controller should be used with a Analog Controller Protection or Over temperature Trip-Alarm.
Outputs could be Relay or SSR, Voltage and Current outputs like 0-10V and 4-20mA are needed sometimes to drive DC/AC Drives or to control Motorized Valves. Relays and SSR can be On-Off or Time proportional (PWM). The Cycle times can be 10-20 Secs for Electromagnetic Relay and around 1 Sec for SSR. This is because Mechanical Relays and contacters have limited number of operations. The zero crossing SSR has to be cycled slower than mains frequency.
Evolution of Temperature Control
Bimetal Thermostat
Analog Dial On-Off Controller.
Analog Dial Proportional Controller.
Digital Display - Analog Controller - On-Off.
Digital Display - Analog Controller - Proportional.
Digital Display - Analog Controller - PID.
Microcontroller Based Process Controller. (On-Off, Prop., Universal TC, RTD, mA Input)
Process Profile Controller (Microcontroller Based).
Microcontroller Based Fuzzy or Auto-Tune PID Controller.
Data Logger, Computer, PLC or SCADA based Solutions.
Even today, the controllers at every stage of evolution, from the thermostat to Auto-Tune, are used in many countries, for many different industrial applications. No solution above is obsolete! The developing Countries still use electro-mechanical or semi-automatic means for control in some areas.
In Curing rubber, which is one of the more complicated process, we need a profile based controller, which also triggers other timers or counters which need to be activated at different segments.
When a very big area is controlled, with materials or load placed un-symmetrically, Every corner or section has to have separate sensor and controller. These are then governed by a SCADA, Supervisory PLC or Master Controller.
Even a Big Die for Plastic Moulding with an Unsymmetrical Object or long object to be moulded; needs compensation for sides which will absorb more heat.
Solid State Relays - These designs were improvements i made on the Application Notes of Motorola Semiconductor (freescale) and Thomson CSF (stmicro) Thyristor Data. The parts are still available, now made by other firms. You can also find similar equivalents.
They are called SSR as there are made of semiconductors and have no moving parts to wear out. They do generate heat depending on load and switching. Thyristors are used in most as they are rugged, mosfets and IGBT may also be used for various applications.
In this section you will find SSR designs and PCB layouts which you can study. These were made and sold by me years ago. So the PCB layouts have gone thru some revisions and they worked quite well.
Many machines and equipment use some SSRs in their products which may need replacement. So the SSR is not only sold to OEMs but also to Service-Maintenance Market. These are also modified as Output Modules for digital outputs coming from embedded systems or Computers.
Electromagnetic Relays - NO - Normally Open
when the relay is not energized or activated, this terminal is open-circuit.
NC - Normally Closed
when the relay is not energized or activated, this terminal is closed circuit.
COM - The Common
Center Terminal in relays. This is the center terminal that closes circuit with NC-NO.
The terminals are potential free and floating and are insulated from the control signals or coil windings by many kilo volts. Many provide visible isolation. These terms apply to SSR or Big Contacters too.
Control panels are a part of industrial automation. It contains many DIN standard instruments both in the front panel and inside back rails along with the wiring. They are called panel mounting and rail mounting. Cable management is a Science in these equipment.
Just like rackmounts hold big instruments or computers, control panels small or big have to hold DIN Instruments, switches and annunciators to make it easy for the operator. The maintenance work also is simple from the backside. It can be kept near the machinery which it controls.
Some Control panels go into Control Rooms at a distance away or at a greater height from the shop floor. This way they can monitor and give instructions while managing a larger process like processing of chemicals and at the same time safeguarding the instrumentation and computers with controlled environments.
