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<div class="moz-cite-prefix">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.</div>
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<div class="moz-cite-prefix">- sgh<br>
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<div class="moz-cite-prefix">On 10/26/20 10:23 AM, Rodney Radford
via TriEmbed wrote:<br>
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<div dir="ltr">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.</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, Oct 26, 2020 at 8:20
AM John Vaughters via TriEmbed <<a
href="mailto:triembed@triembed.org" moz-do-not-send="true">triembed@triembed.org</a>>
wrote:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">>You
might avoid the ADC chip and instead use an Arduino.<br>
<br>
+1<br>
<br>
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.<br>
<br>
Just some thoughts<br>
<br>
John Vaughters<br>
<br>
On Monday, October 26, 2020, 7:14:39 AM EDT, John Moore via
TriEmbed <<a href="mailto:triembed@triembed.org"
target="_blank" moz-do-not-send="true">triembed@triembed.org</a>>
wrote: <br>
<blockquote type="cite">You might avoid the ADC chip and
instead use an Arduino. Some Arduino's give an 8 channel
ADC at 10 bits resolution. <a
href="https://www.arduino.cc/en/Tutorial/Foundations/AnalogInputPins"
rel="noreferrer" target="_blank">https://www.arduino.cc/en/Tutorial/Foundations/AnalogInputPins</a><br>
<br>
-John Moore<br>
<br>
On Sun, Oct 25, 2020 at 10:34 AM The MacDougals via TriEmbed
<<a href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>>
wrote:<br>
<blockquote type="cite">I am looking for an 8 channel ADC
chip.<br>
10 bit is sufficient. I2C is preferred but SPI would be
OK.<br>
Hand solderable package highly preferred.<br>
I found these:<br>
<a href="https://www.ti.com/lit/ds/symlink/adc128d818.pdf"
rel="noreferrer" target="_blank">https://www.ti.com/lit/ds/symlink/adc128d818.pdf</a>
- $5.30 at DigiKey<br>
<a
href="https://www.analog.com/media/en/technical-documentation/data-sheets/2309fd.pdf"
rel="noreferrer" target="_blank">https://www.analog.com/media/en/technical-documentation/data-sheets/2309fd.pdf</a>
- $7.34 at Digikey<br>
<br>
Any opinions? Anyone have something in their personal
stock?<br>
Anyone interested in sharing shipping costs on a DigiKey
order?<br>
<br>
---> Paul<br>
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