help req:

[ammar ali]

Hi every 1:
i m designing a data acquisation project with thermocouple used to measure temperature.i want to interface adc's o/p 2 labview for analyzing the temp,,if any 1 knw abt serial interfacing with pc without using micro-cont: b/c i m new to the field..

cheers:

 

[joydeepsarkar87]

Which PIC ic u are using?? PIC ics generally have UART through which you can have serial interface with PC only thing u require is a level shifter i.e., MAX232 and RS232 cable connected to the Serial port of the PC and you can view ur results in the hyperterminal.

Can you give more explainantion about ur project??

 

[ammar ali]

dear i don't want to use microcontroller but instead i want 2 serially interface my ckt with pc and then want to analyze my data(of temp,voice etc) with the help of labview...
i m only thinkin to use adc then uart then through rs232..

 

[mrcube_ns]

You want to measure temperature with thermocouple, than to convert that with adc and to read with labview via RS232.

First of all thermocouples gives very small voltages over temperature range, a few mV, so first you have to amplify this voltage to some range e.g. 0-5V.
This could be tricky because you need big gain and consequently you amplify and tempearure signal and all noise around...

Generally you have to build thermocoupler to RS232 converter, this will be much easier with mcu. Please think again about non using mcu.

Labview must have some RS232 protocol,so, you have to make that your converter interpret measured temperature in some fixed message format.


Mr.Cube

 

[ammar ali]

thnx 4 ur suggestion dear,,but the problem z i have never used a mcu..so if u kindly give me a little bit reference abt how 2 use it in this case(like which mcu n coding)..
i will b very thankfull 2 u>

 

[mrcube_ns]

TC ----- Amplifier ------- ADC on MCU --------- MAX232 --------- Serial port on PC ------- Labview
````|------------------------ Your PCB --------------------------|

About amplifier see:
AD595 | Type K Thermocouple Amplifier with Cold Junction Compensation | Analog Temperature Sensors | Sensors | Analog Devices
of find something similiar.

For mcu, I use PIC microcontrolers, thay can have ADC integrated (10bit resolution, which is OK for most applications).
Generally your mcu should have ADC and serial port, than it will be much easier to do everything.


I continue in next post because there is some stupid limitation of 1000 characters per post!@$#%^&@%^%$&@^%

Mr.Cube

 

[mrcube_ns]

Next part:

See Microchip Technology Inc. is a Leading Provider of Microcontroller and Analog Semiconductors, providing low-risk product development, lower total system cost and faster time to market for thousands of diverse customer applications worldwide., series PIC16Fxxxx have lots of mcu's which have adc and serial port integrated simultaneously.

You have to make software for mcu which reads analog input (temperature e.g. 0-500C as voltage 0-5V). Convert ad voltage to physical value, and than send it over serial port in some protocol. I never use labview, so I suppose you know it's protocol.

Max232 you need for convert TTL serial level (0-5V) to RS232 serial level (-12V to +12V).

My advice is to use google with key words like:
Thermocouple amplifier
Max232 application or schematics
etc..

Hope I helped!

Mr.Cuibe

 

[ammar ali]

thats helpful buddy,,,thnx....

 

[ammar ali]

dear cuibe: if u can suggest that what procedure for parallel interfacing adc's o/p with pc without using mcu???