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Help choosing product that can transmit Modbus RS485 long range LOS

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Hello All.

I have been frustratingly over the last couple of weeks trying to get some feedback from Digi using the support contact method. It has led me back to the beginning again, drawing blanks.

I'm trying to ascertain what Xbee product can transmit Modbus RS485 over long ranges.
My focus is on the small modules, "Bare bones" no enclosure as it needs to integrate into an existing small plastic enclosure.
Ideally it is a plug and play module, some configuration on the XCTU software is OK, i have no coding abilities so this would have to be a no go.
I have had conflicting, advise from 2 Digi technical support techs, leaving my confidence short.
I was interested in the Xbee 900hp-pro, i was told this would need an MCU to interface the Modbus protocol and be able to transmit. I have read on some other posts about the Xtend device.
This is the most promising lead yet.
Please could some one help me and explain to me how i can achieve the above request.

I would be so happy if you could help.

Kind regards

asked Jun 2, 2017 in RF Solutions and XBee by smithtek New to the Community (2 points)

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2 Answers

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What country do you want to use the product in?

If it is in the U.S. or Canada, then either the 9xtend, 900 HP or XBe PRO SX would work. Just note that none of these OEM module will communicate with an RS485 device without the use of a CMOS to RS485 driver chip placed between the RS485 connection and the radio. This chip will connect to the radios DI, DO and TX Enable lines thus allowing the radio to talk on an RS485 connection.
answered Jun 2, 2017 by mvut Veteran of the Digi Community (15,410 points)
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Hello mvut.

Thanks for getting back mate.
Could you point me to some examples of the cmos converters you was talking about please ?
Somthing like this
Would this wired as per your instructions allow for the transmition to happen automatically .?

Thanks again
answered Jun 2, 2017 by smithtek New to the Community (2 points)
http://www.linear.com/product/LTC1480 is more in line of what I am referring to. The one on Sparkfuns web site is a 5V TTL level to RS485 and you want a 3V CMOS to RS485 level shifter.
And another here.


Thanks for hanging in here with me Mvut.
I did come across the LTC1480 whilst on my epic search through the net.
I suppose this could be connected through a bread board for testing purposes.
Would you know if this chip or something very similar from another supplier exists.
These are some examples i found, but due to my lack of electronics knowledge i cannot decipher if they are suitable.




Hopefully i can narrow this down to a pre-assembled interface.

Thanks again :
Hello Mvut.

So the board you suggested  http://www.satistronics.com/rs485-board-33vrs485-transceiver-uart-communication-board_p4113.html

this would interface directly with the Xbee given i connect the correct terminals of the board to the correct pins of the Xbee.

Would you have any advice on how to do this ?
Question. Do you contract for services like this ?
If so email me directly and we can discuss the possibility of some work.


Thanks again
You will want to check its documentation but from what I can tell, you would connect the Ro and DI sides to the Xbee and the screw terminals to the RS485 device.