How to display various parameters (voltage, current and temperature) on 7-segment display every 5 seconds

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chineetim

Joined Nov 6, 2019
1
I have built an op-amp series pass voltage regulator, whose output is inputted into an analog-to-digital converter (ADC0804). The ADC's output is connected to a CoolRunner II CPLD Starter Board. This output corresponds to a value on a look-up table, which determines what value would be displayed on the screen.

I also have two more look-up tables: one to display the current through the output, and one which would correspond with the voltage across a temperature sensor (LM35), to display the temperature of the series pass transistor.

Currently my ADC can only display one parameter at a time, as only one of these voltages can be applied to the input of the ADC at any given moment. Is there any way to have the inputs to the ADC alternate every 5 seconds? Another problem would be that this input switch would need to be in sync with the information programmed onto the CPLD, since when voltage is being displayed, it would correspond with a certain value on a lookup table and the unit "V" would be displayed after the value. When current is being displayed, it would correspond with values from another lookup table and the unit "A" would be displayed after the value. Lastly, the voltage across the temperature sensor would correspond with the temperature from a different lookup table, and "C" would be displayed after the value.

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ci139

Joined Jul 11, 2016
1,696
your options
(-1-) "buffer"/filter sensor inputs -- e.g. -- provide minimal conditioning and amplification to your sensors , then analog mux them to the ADC
(-2-) use 3 ADC-s -- mux them to your main processor / or store to additional storage (RAM/FLASH) with time-KEY records (avail for sys at any time)
(-3-) display all at once on a multi-line LCD/LCD-s
(-or-) define a preference of your own

danadak

Joined Mar 10, 2018
4,057
Consider the following comments for future design work.

This is a single chip, PSOC, has onchip +/- 1% reference for its SAR A/D,
most resources left unused per your design requirements. IDE and Compiler
free, board for this is small USB board, $10. This particular chip very low end, a high end board with 20 bit DelSig and a lot of other resources also$ 10.

The SAR I configured current measurement input as differential so that you
can take off V of a shunt for measuring current. The other two channels
configed as single ended, for T and V measurement.

The LCD is an onchip interface, can be graphic or I2C or SPI.....

Right hand window shows resources used/left....

You drag and drop components (a component is an onchip resource) onto design canvas,
wire up internal and external to pins with wire tool, then right click component, pick datasheet,
and it has all the APIs explained to manage the component while you are coding. Very simple.

A catalog of onchip components, for the higher end parts (lower end have less capability), attached.

For example there are also OpAmps onchip you could use for gain up and offsetting signals.

Regards, Dana.

PS : I missed the fact you want to use 7 seg LED, in the higher end part there is a controller component for that.
You also use a CPLD to do table translation, PSOC also has LUTs for that. However you do not need that for display
as LED controller takes care of that.

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