[TriEmbed] ADC

[Rodney Radford]

I know what RS485 is used for - the issue I initially raised is the code at
the Arduino site is specific to the RS485 add on card and will not work
with the serial port without modifications. John later provided a link to
the modbus implementation he had used that was configured fo serial port
use.

On Tue, Oct 27, 2020 at 3:37 PM Scott Hall via TriEmbed <
triembed at triembed.org> wrote:

> Modbus can be used over a TTL serial link -- as long as you take
> electrical characteristics into consideration.  In fact, modbus has been
> used in many connection types, even parallel buses and wireless links.
> I've even seen modbus embedded in another protocol layer, such as Zigbee,
> MQTT or of course TCP.  A RS485 link requires a balancing circuit or
> transformers at either end and is really designed for long or multidevice
> signaling, and not needed for short wire or direct bus connections in close
> proximity.
>
> - sgh
>
> On 10/26/20 10:23 AM, Rodney Radford via TriEmbed wrote:
>
> I have not used the modbus Arduino code before, but it does look
> interesting. However in reading the description they state it is designed
> to use with either their Ethernet shield or the RS485 shield, but I did not
> see anything on running it with just a standalone Arduino. If it is
> possible to just use the TTL serial port of the Arduino, that would be very
> nice, indeed.
>
> On Mon, Oct 26, 2020 at 8:20 AM John Vaughters via TriEmbed <
> triembed at triembed.org> wrote:
>
>> >You might avoid the ADC chip and instead use an Arduino.
>>
>> +1
>>
>> My favorite combo is to use the Rpi UART with a nano arduino that has 8
>> ADCs @ 10bit and you can get them for like $5. I like to make the ardiuno
>> dumb with a modbus slave. The combination with the UART/MODBUS is extremely
>> reliable. You can also pump it out to tcp with the mbusd utility.
>>
>> Just some thoughts
>>
>> John Vaughters
>>
>> On Monday, October 26, 2020, 7:14:39 AM EDT, John Moore via TriEmbed <
>> triembed at triembed.org> wrote:
>>
>> You might avoid the ADC chip and instead use an Arduino.  Some Arduino's
>> give an 8 channel ADC at 10 bits resolution.
>> https://www.arduino.cc/en/Tutorial/Foundations/AnalogInputPins
>>
>> -John Moore
>>
>> On Sun, Oct 25, 2020 at 10:34 AM The MacDougals via TriEmbed <
>> triembed at triembed.org> wrote:
>>
>> I  am looking for an 8 channel ADC chip.
>> 10 bit is sufficient.  I2C is preferred but SPI would be OK.
>> Hand solderable package highly preferred.
>> I found these:
>> https://www.ti.com/lit/ds/symlink/adc128d818.pdf  - $5.30 at DigiKey
>>
>> https://www.analog.com/media/en/technical-documentation/data-sheets/2309fd.pdf
>> - $7.34 at Digikey
>>
>> Any opinions? Anyone have something in their personal stock?
>> Anyone interested in sharing shipping costs on a DigiKey order?
>>
>> ---> Paul
>>
>>
>>
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