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Thank you Klaus for your feedback.
Could you explain to me more simply what you wrote to me ? I understand the 100 mV / 1.1 V ratio. But I'm afraid I didn't understand the whole thing well. Thank you.
Concerning external Vref I will plan to use « LM385 Adjustable Micropower Voltage References » with a Vref of 1,3 V. Have to modify the MikroC source, calculations and setting VCFG0 - Voltage Reference bit of ADCON1 register of PIC16F887 to 1.
Thank you for your feedback.
Concerning LM35 and measurements of negatives temperatures, i tested the circuitery showed in the datasheet, here under. It works not too bad (except problem of ADC with VCC as Vref).
Eric
1) Calculation of the mounting characteristics for a full-scale variation of the ADC :
I chose a measurement range between -10 °C and +100 °C with a 10-bit analog/digital conversion, i.e. from 0 to 1023, i.e. 1024 values. In absolute terms, the temperature range is therefore 10 °C + 100 °C...
Regarding your recommandations after these experiments with LM35CZ, LM135 and MCP9701A, I will switch to DS1820 and will try LM73. I didn’t know this last device.
1707573421
OK.
Instead of using next time CAN (Convertisseur Analogique Numérique) i will use « ADC ».
No worries, i can find by...
CAN, means Digital Analog converter in French. Looking at the link indicated above in my first message and looking at the datasheet of the 16F887 it seems that from the ADCON1 register we can indicate to the CAN another voltage range on which to make the conversion rather than 0 - 5V (VDD) ? -...
The PIC 16F887 has a 10-bit analog / digital converter. With an LM35CZ or an LM135 or an MCP9701A I would like to measure temperatures between - 10°C and + 100ºC. For example, knowing that the LM35CZ delivers 10 mV / °C, the voltage range on its pin 2 (Vout), will vary from - 100 mV to + 1000...
Thanks,
MCP9701A works well. Displayed temp on LCD meets room temp displayed on an digital thermometer. Needed to write a new mV to ºC formula according datasheet and considering the offset for negative temp.
Now I plan to put MCP in a steel tube for different measurements. Have already an...
Thanks Brian.
« The ADC input voltage and the LCD reading are in accord, aside from possibly being scaled by 10 so the ADC itself seems to be working OK. » : It is my opinion too.
Multimeter was on
Thank you Paul.
Made corrections.
👍🏻
1703934005
Thank you Brian.
Concerning your feedback « The...
Dear Brian,
Regarding your advices, here under is the table of measurements values and the code in the attached file :
Almost for each voltage value set every 0,25 V with potentiometer (values displayed on Multimeter > first column), voltages values dispayed on LCD (second column) switch to...
Merci !
I did that. When room temperature is 23°C, voltage between Vout (pin 2) and GND (pin 3) of LM35 is 230 mV … But when displayed temp on LCD change every 5 sec (due to the delay in my code) as shown on attached pics, temp is consistent only once every four samplings.
😕🤔
1697545394
Merci ...
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