Well here is a great link describing nearly about everything there is to learn on using digital multimeters.
Saturday, December 25, 2010
Monday, December 13, 2010
Tuesday, December 7, 2010
Thermocouple Temperature Sensor.
Hi Guys, this is yet another a great resource for those who are interested in thermocouples.
Introduction
A thermocouple is simple two wires of different material with one side of the ends joined and the other opened.
It works on the phenomena of the thermoelectric current. Means that when both the ends (joined and opened) are subjected to temperature difference, then a small amount of EMF is produced. The question is how "small" is this EMF.
This EMF is just a few micro volts! Too low to be used in any kind of circuits. So what next?!!
Since this EMF is too low to be used and is susceptible to contain noise form the environment, we need to amplify the signal and then filter it. But that's not it!
There is more to it.......for detailed info look at the document below and if you have any question please feel free to contact me.
Introduction
A thermocouple is simple two wires of different material with one side of the ends joined and the other opened.
Real Thermocouple
Thermocouple Diagram
It works on the phenomena of the thermoelectric current. Means that when both the ends (joined and opened) are subjected to temperature difference, then a small amount of EMF is produced. The question is how "small" is this EMF.
This EMF is just a few micro volts! Too low to be used in any kind of circuits. So what next?!!
Since this EMF is too low to be used and is susceptible to contain noise form the environment, we need to amplify the signal and then filter it. But that's not it!
There is more to it.......for detailed info look at the document below and if you have any question please feel free to contact me.
Sunday, December 5, 2010
Introduction to BreadBoard!
For those who are just starting prototyping their projects but having trouble using the bread board.
Wednesday, December 1, 2010
How to implement PID controller !
So here it is guys!
PID Controller Implementation.
Lets start with the implementation assuming that all of you have good knowledge of PID theory. If not, then there are lots of book and material available on the internet.
There are two ways to build a controller:
-Analog controller
-Digital Controller
Lets just stick to analog controllers at this moment.
Analog controllers
Analog controllers are usually build using traditional operational amplifiers
Design 1: Ideal PID algorithm
Below is a simple inverting amplifier.
The equation (transfer function) of this amplifier is
V2 / V1 = – Z2 / Z1
Now replacing Z1 and Z2 with a resistor and capacitor, we have the following op amp below.
Using some ECA (Electrical Circuit Analysis) , we have
V2 / V1 = – {(Rf / Ri + Ci / Cf) + (1 / RiCfD) + (RfCi) * D} = – {Kp + Ki / D + Kd D}
Hence the PID controller is :
PROPORTIONAL GAIN is Kp = (Rf / Ri + Ci / Cf),
INTEGRAL GAIN is Ki = (1 / RiCf), and
DERIVATIVE GAIN is Kd = RfCi.
Choosing the right values of the resistors and capacitors will lead to a better controller.
Design 2: Parallel PID algorithm
This is the best method to implement the controller since it is very robust and easily tunable. Below image summarizes how it works.
This is how it is implemented,
PROPORTIONAL GAIN is KP = (R2p / R1p),
INTEGRAL GAIN is KI = 1 / (R1i C1i), and
DERIVATIVE GAIN is KD = (R1d C1d), and
CASCADED GAIN is KC = (R2C / R1C).
You can easily use variable resistors and capacitors to get a tuned response.
Design 2: Series PID algorithm
Here the controller is a product of PI controller and PD controller. Following is the diagram:
DERIVATIVE GAIN is KD = (R2i R2d C1d) / R1i.
So guys, this was short tutorial on how to implement a PID controller using an op amp.
For detailed information, derivation and an implemented example please see this.
Please let me know what you think about this post! Do comment.
Have fun.
PID Controller Implementation.
Lets start with the implementation assuming that all of you have good knowledge of PID theory. If not, then there are lots of book and material available on the internet.
There are two ways to build a controller:
-Analog controller
-Digital Controller
Lets just stick to analog controllers at this moment.
Analog controllers
Analog controllers are usually build using traditional operational amplifiers
Design 1: Ideal PID algorithm
Below is a simple inverting amplifier.
The equation (transfer function) of this amplifier is
V2 / V1 = – Z2 / Z1
Now replacing Z1 and Z2 with a resistor and capacitor, we have the following op amp below.
Using some ECA (Electrical Circuit Analysis) , we have
V2 / V1 = – {(Rf / Ri + Ci / Cf) + (1 / RiCfD) + (RfCi) * D} = – {Kp + Ki / D + Kd D}
Hence the PID controller is :
PROPORTIONAL GAIN is Kp = (Rf / Ri + Ci / Cf),
INTEGRAL GAIN is Ki = (1 / RiCf), and
DERIVATIVE GAIN is Kd = RfCi.
Choosing the right values of the resistors and capacitors will lead to a better controller.
Design 2: Parallel PID algorithm
This is the best method to implement the controller since it is very robust and easily tunable. Below image summarizes how it works.
This is how it is implemented,
PROPORTIONAL GAIN is KP = (R2p / R1p),
INTEGRAL GAIN is KI = 1 / (R1i C1i), and
DERIVATIVE GAIN is KD = (R1d C1d), and
CASCADED GAIN is KC = (R2C / R1C).
You can easily use variable resistors and capacitors to get a tuned response.
Design 2: Series PID algorithm
Here the controller is a product of PI controller and PD controller. Following is the diagram:
The PID controller:
PROPORTIONAL GAIN is KP = (R2i R2d / R1i R1d + R2d C1d / R1i C1i),
INTEGRAL GAIN is KI = R2d / (R1d R1i C1i), andDERIVATIVE GAIN is KD = (R2i R2d C1d) / R1i.
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For detailed information, derivation and an implemented example please see this.
Please let me know what you think about this post! Do comment.
Have fun.
Virtual Reality; get delusional
Watch the following clip and you will be amazed how a simple reverse technique can make u delusional, and makes u think a simple 3D model being actually real.
