Pre-Engineered solution for wireless signal transmission.

Thread Starter

AustinS

Joined Aug 9, 2018
9
Hello all, and thank you for taking the time to look at my post!

I am looking for a pre-designed product which will analyze an incoming signal and simply transmit it over some distance while outputting the correct voltage.

The only caveat I see is that it has to sample at over over 9,600 bps. Another is that, both the transmitting micro controller and receiving micro controller have to know how to translate the wireless signal back to the original signal.

I have seen things such as RS-485 repeaters and the like, but I am just trying to see if there is a product on the market which is more or less 'plug and play'.

upload_2018-8-9_10-14-36.png

Thank you for your help.

Best,
Austin
 

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BR-549

Joined Sep 22, 2013
4,938
It depends on all the little details you have left out. Like the incoming signal. Different signals are detected in different ways. What do you want to analyze? Then what do you want to simply transmit.....the result of analysis or re-transmit the incoming signal?

Some signals, such as audio and video have plug and play options. Other hobby signals have become common....and certain modules and software for common signals(temp, air pressure,etc) are standard and could be thought of as micro processor plug and play.

It depends on what you're doing.
 

Thread Starter

AustinS

Joined Aug 9, 2018
9
From my research I've conducted so far, it looks like I can simply use a pre designed board which converts my signal to RS485.

I've discovered a RS485 wireless transmitter and receiver pair and now I need to discover if I can invert the aforementioned board to convert RS485 to D3NET.

If that is successful, I will need to find a digital buck/boost circuit to boost the signal to the appropriate voltage.

I do not believe an analog buck/boost circuit will be appropriate as this signal is digital in nature and the capacitors and inductors in an analog buck/boost circuit would prevent the signal from getting through appropriately.

Can anyone recommend a digital buck/boost circuit that operates over 9,600 bps? Does that question even make sense?
 

MrChips

Joined Oct 2, 2009
22,099
By definition, RS-485 is a wired mode of serial transmission. There is no such thing as wireless RS-485.

What you are asking is RF transmission of UART data.

You can create a wireless link and can modulate the carrier any way you wish. Data is usually packeted in some form so as to incorporate error detection and correction, security, encryption, etc. You are not limited to just sending and receiving NRZ (non-return to zero) UART data. Phase-encoded modulation is preferred,.
 

Thread Starter

AustinS

Joined Aug 9, 2018
9
CORRECTION:

"FROM "KeepItSimpleStupid" ' RESEARCH*** it looks like I can simply use a pre designed board which converts my signal to RS485."
 

Thread Starter

AustinS

Joined Aug 9, 2018
9
By definition, RS-485 is a wired mode of serial transmission. There is no such thing as wireless RS-485.

What you are asking is RF transmission of UART data.

You can create a wireless link and can modulate the carrier any way you wish. Data is usually packeted in some form so as to incorporate error detection and correction, security, encryption, etc. You are not limited to just sending and receiving NRZ (non-return to zero) UART data. Phase-encoded modulation is preferred,.
You're certainly correct!

I understand that the waveform being transmitted wirelessly probably does not resemble RS485.


However, Looks like there are plenty of products that transmit RS485 wirelessly.
 

MrChips

Joined Oct 2, 2009
22,099
RS-485 is a signal voltage protocol, not a serial transmission protocol.

You can set up any RF receiver to receive serial data and interface it to TTL, RS-232, RS-485, etc.

RS-485 only determines the voltage levels that are output from the interface.
 

MrChips

Joined Oct 2, 2009
22,099
You're certainly correct!

I understand that the waveform being transmitted wirelessly probably does not resemble RS485.


However, Looks like there are plenty of products that transmit RS485 wirelessly.
You are misinterpreting what you see in the ads of such products.
 
There is an electrical interface and a protocol interface.

I need to refer you to the OSI model: https://en.wikipedia.org/wiki/OSI_model

RS232 really got bashed. It was more like the method to control the Bel 103 modem, had 25 pins and had a +-25V signal level. This happeneed when IBM made the 25 pin connecter 9 PIN.

MODBUS can't get their nomenclature correct. It's a multi-slave (up to 32) with differential transmission, so it does long distances well with a wire.
It's usually very hard to get your first MODBUS thingy to work. Terminators are required on both ends of the bus.

I have a router that I can use as a repeater, access point and a router.

I had a "repeater" that could not be used as a router, but could be used as an access point on it own or different network, a repeater (It repeted a specific MAC address, It can do wireless to wired conversion and vice versa. It can also be used to replace an Ethernet wire with an encryped wireless pipe.

and if your worried, you can probably put the serial servers on a VPN. A bit harder, but still doable.

So, you keep the building automation system on a separate network, just like in a more secure installation, you keep the management ports on a totally different physical network.
 

Thread Starter

AustinS

Joined Aug 9, 2018
9
RS-485 is a signal voltage protocol, not a serial transmission protocol.

You can set up any RF receiver to receive serial data and interface it to TTL, RS-232, RS-485, etc.

RS-485 only determines the voltage levels that are output from the interface.
Based on the little information I have read, it looks like a transmission protocol as it uses a particular organization of a start, stop bit and a parity bit. Is this what you mean by protocol?

https://upload.wikimedia.org/wikipedia/commons/f/f2/RS-485_waveform.svg
 

Thread Starter

AustinS

Joined Aug 9, 2018
9
MODBUS can't get their nomenclature correct. It's a multi-slave (up to 32) with differential transmission, so it does long distances well with a wire.
.
Does that mean you can have one master and 31 slaves? Does differential transmission mean you compensate for expected lag of the current's phase angle in an inductive transmission line?
 

Thread Starter

AustinS

Joined Aug 9, 2018
9
Looks like when I output my final signal, I will need to boost the voltage.

I am used to using a simple buck.boost circuit for simple DC values but I have no idea where to begin when it comes to boosting a digital signal that needs to be sampled at a certain bps....
 
Based on the little information I have read, it looks like a transmission protocol as it uses a particular organization of a start, stop bit and a parity bit. Is this what you mean by protocol?
NO, see https://www.rtaautomation.com/technologies/modbus-rtu/

It's a message or packets. The medium can change. Take DSL for example. You have a modem with an Ethernet port. it puts some modulation of the phone line and keeps the DC path and the voice bandwidth open. See: https://en.wikipedia.org/wiki/Digital_subscriber_line

DSL might atcually use the ATM protocol. https://en.wikipedia.org/wiki/Digital_subscriber_line

Also see: https://www.techopedia.com/definition/3163/digital-subscriber-line-access-multiplexer-dslam

RS485 is not like an antenna signal. MODBUS sends packets. The packets get changed a little based on the media it's transported over.
Ethernet is routeable; Standard RS485 or MODBUS over RS485 is not.
 
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