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Smarter Life

15 Posts authored by: malamitra
Thanks a lot Linas, for your interest. I have got my internet recharge an hour back and writing a reply. I have attached a zipped file of the project here. I wanted to check the project by programming the kit. But I kept the kit in my college. On Monday I'll check it. If this is a wrong file I'll let you know. The program takes a step profile given in the array tempdiff, applies PID scales tempdiff in the range 0 to FE. tempdiff=0 is scaled to 7F. In i2c debugger / the bridge control panel this ...
Now, I am writing the final update though I really do not want to write it at this stage. But somehow I have to do it by tonight. My internet service pack will be over by 12 midnight and I have to recharge. I may not have the facility tomorrow. Objective of the project: To control the oven parameters e.g. temperature, pressure with PID type of control. Selection of the parameter depends upon the availability of the sensor and ease of actuation. PID will be tried both in software and hardware. ...
Subject: PID is working!!     I am very happy to tell you that PID is working. But lots of loose contacts. I put the discrete components on bread-board. I could not get the right kind of bread-board wire. What I have got is multi-strand wire not at all useable on the bread-board. Now, I am soldering the components on a general purpose PCB. ...
Topic: Electronic component purchase, testing and interfacing Yesterday my whole day was spent on S P Road, Bangalore for component and accessories purchase. After spending 3 days for purchase I could get the bare minimum. I am using LM35 for temperature sensing, IRF830 MOSFET for current control of the heater. LF356 op-amp for scale changing of MOSFET gate input voltage. The DAC is giving the analog voltage of 0 to 3.41 volt. The threshold of MOSFET varies from 2 to 4 volts according to dat ...
The files could not be inserted here. It is attached below. ...
Topic: PID in hardware Keywords: Op-amp, differentiators, integrators, simulation, TINA-TI For implementation of PID dual-supply op-amps are required. A positive supply op-amp can be used with the input given at the non-inverting terminal. In that case, the output is PI and PD for integrator and differentiator configuration respectively. But if the function slope is less than 1 the output tries to become negative for a differentiator. For a positive supply op-amp this gives a zero or err ...
Topic: PID in software   I wrote the code for the numeric differentiation and integration and applied for PID control. The control loop is not complete. The PID works on an artificial temperature difference profile. I have not received the components from element14. So I could not complete the control loop. On Tuesday, I purchased most of the components from the local market. It was overcrowded, I had to spend the whole day there. But I could not finish the purchase. I have to go agai ...
Topic: I2C Communication I started with op-amp testing and came to know that, off-chip components are not available on the board. I already requested those from element 14 in apprehension. Now I am waiting for the resistors and capacitors. I am not getting any response from element 14, Bangalore. Meanwhile, I am writing the PID in software. For code testing purpose, the variable values need to be communicated to host. I am trying I2C. I am implementing this for the first time. Gagan Luthra ...
I started with the op-amps. I put it in the non-inverting mode,  I measured the voltage at the Arduino compatible I/O header J2.  I could measure only digital voltage VDD = 3.42 volt. When the noninverting input is connected to VSS the output becomes zero. There is no in-between value. Though  I  selected 3 analog pins. I took one example for op-amp. For this also no analog output. If the pins can give only digital output then why analog pins are listed in components? Next I' ...
I completed a small part of the project, Here, the blue LED indicates the status of control parameter say, temperature. When there is a temperature difference the blue LED blinks. When the temperature sets in the light becomes steady. Earlier I thought of changing the duty cycle according to temperature difference. But our eyes are not sensitive to such small differences. Also, as mentioned in documents the clock pulse duration is not very accurate at low pulse rate. ...
I was quiet for a week. I had an installation problem. I purchased a new laptop. Selection of laptop and installation of software took lots of my time. Installation is still going on. PSOC creator installation was quite fast. Now I am creating a small part of the project. The red=green LED-s will turn greener as the temperature sets in. If not, the light turns redder. I am in-between and posting this blog. As I promised to Victor I'll post a blog by Friday. The main.c file has the artificially c ...
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In post 2, block diagram for control voltage implementation was given. This control voltage can be actuated in many ways. The standard technique is PWM i.e. longer off time for the control pulse or less duty cycle that keeps the heating coil off for a longer time when the actual temperature is more than the set-point temperature. As DAB pointed out rightly, this may give too many on-offs, an undesirable effect. A smooth control is possible by use of a Voltage Variable Resistor (VVR). VVR may be ...
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