PLC based PID Controller

Below is a Electrical Control Panel, It has a Strip Chart Recorder which is electro-mechanical, It has a PLC Inside. A handheld PLC Programming unit. The computer is showing the Ladder Logic Program. PLC is based on a embedded uC. The DIN Controllers are Analog + Digital circuits. So you see it is a Electrical Control Panel with Electronics and the PLC Ladder Logic means, Software too.

Process Control Application Notes

This is a PID Controller based Control Panel using a PLC from GE Fanuc Automation. The Computer is a 386 40MHz with 40MB HDD.

PID Controller PLC

Electrical Control Panel Wiring

Control panes have many DIN Instruments like Indicators, Controllers and Recorders. They also have in the back end contacters, drives and circuit breakers with orderly wiring and cable management.

Astable Multivibrator with 555

This is a demo of the popular 555 timer. you can try out the project on this page by a javascript simulation.Press the Red button below to turn on the circuit press it again to turn off. The 555 can source (LED2) or Sink (LED1) upto 200mA.

Screenshot of Astable 555 Timer Flasher

It can even drive a small motor or lamp with diodes added to protect from inductive kickback.Vary Ra, Rb and Ct with the controls given and see the change of frequency, period and duty cycle.

Screenshot

Astable Multivibrator with 555

Astable Multivibrator with 555

This is a tutorial with calculator to help learn the application of 555 which is a very rare chip innovation. It is simple, versatile, flexible and programmable (by tweaking of pots).

Mini RTD Pt100 Three Wire Transmitter

These are the circuits and boards of a Mini Temperature Transmitter for a Platinum hundred ohms temperature Sensor.

Transmitter RTD

The customer wanted a two wire system, this needs low power opamps which were ten times the price. If this transmitter works at 3mA it could have been two wire. Those parts were in short supply and the budget of customer was low. So i made it with regular opamps but three wire. The customer was satisfied as he got a cost effective solution. But now the situation of markets and products are different.

RTD  Three Wire Transmitter

If you need to transmit the temperature from a high voltage area or toxic environment. You will need to hermetically seal the transmitters, convert the Voltage to frequency, frequency to IR LED flashes or RF. This can be then remotely monitored. Then the transmitter has to be battery-solar operated, low power too. ICL7135 is a simple solution. It has a serial output that can be used to Drive IR Leds. Remotely sense these flashes in a Micro-controller and you have a reading. You may be able to use optic-fibers too. Where volatile liquids are present so that the risks of sparks can be eliminated.

3 Wire Transmitter RTD

More at Process Control Circuits

This is the same Mini RTD Pt-100 Transmitter but in its case. Encapsulated in epoxy, hermetically sealed against harsh industrial environment. This will work well even near fumes of Ammonia with no corrosion. But not near vapors which can be ignited by sparking as terminals are still open. The side view shows zero and full scale ten turn bourns trimpots heads, for calibration. After cal it can be sealed with RTV compound.