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RS-485 Multi-port hub with LOR Network


mike carlson

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Hey All.. Dose anyone know if this will work ?? ( RS-485 8-port expansion hub from RCS )

http://www.resconsys.com/index.htm

In my situation I would like to have both indoor and outdoor LOR networks, running two cables ( in and out ) to daisy chain would be impractical, I would like to run a star wired configuration for indoors, one wire to each controller from a central location ..



I have used these RS-485 hubs in my Home Automation network with great success.



Any thoughts on this???



Thanks..

Mike..

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mike carlson wrote:

Hey All.. Dose anyone know if this will work ?? ( RS-485 8-port expansion hub from RCS )

http://www.resconsys.com/index.htm

In my situation I would like to have both indoor and outdoor LOR networks, running two cables ( in and out ) to daisy chain would be impractical, I would like to run a star wired configuration for indoors, one wire to each controller from a central location ..



I have used these RS-485 hubs in my Home Automation network with great success.



Any thoughts on this???



Thanks..

Mike..





When I forst clicked on that url you supplied I thought, you want to use a Thermostat for this??? had to dig deeper to locate what you were talking about.

For others that have no idea what this is, here is a DIRECT LINK to the product:

http://oldsite.rcstechnology.com/products/accessories/rs-485_hub.htm


Don't know if that will work or not. Says half duplex output, so I'm thinking possibly not. As I think LOR uses FULL Duplex (if I'm not mistaken.)

Why not just use an LOR USB485B and connect the outside to one of the cat5 jacks and the indoor controllers to the 2nd jack on the unit? Seems this would work to me. At least this is how I would try to do it. This way one cable goes outside, the other cable stays inside.
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I run 20 controllers outside and 3 controllers inside. I also have 4 firefli controllers outside. (They are run

My LOR controllers are set up like Orville suggest.

__________Cat 5 to outside controllers.
USB485B <
__________Cat 5 to first inside controller.

At my first inside controller I have a ELL (easy light linker) this feeds the signal to the other 2 controllers that are inside.

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Orville wrote:

As I think LOR uses FULL Duplex (if I'm not mistaken.)

No, LOR uses half duplex, just like that box. A full duplex connection would use one pair for transmit and another pair for receive. LOR uses a single pair for both transmit and receive. (The other pair is used to send DC power to accessories such as the ELL, the SC485, or the RS485REP.)

Since the LOR network is a RS485 network, I say this expansion hub would work just fine.

However, it looks like expensive overkill to me. You could use a single LOR RS485 repeater to get a network with up to 4 ends. Would that be enough?
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You mention LOR sending DC power to accessories over the line. Do you think that power would mess with the expansion hub or do you think it would just pass right thru?

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Hey Guys.. Thanks for the response, sorry about the wrong link, too fast on the cut and past. I kinda thought the LOR network was half-duplex but was not sure. How do you get 4 ends from that LOR repeater, I see one in and only two out?? with the LOR repeater @ $90.00, and only two runs, for aprox $180 I can get 8 separate 4000’ runs, WOW!! I think maybe I will try and take down one of my home automation networks and try this unit on a LOR controller, as for power , this hub has it’s own 12 Volt power supply and will supply power to the device if hooked up..



Thanks..
Mike

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garyfunk wrote:

Yeah, what Jeff said.


I must have read this a thousand times, it a thousand posts,...and it still cracks me up!
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Steven wrote:

Orville wrote:
As I think LOR uses FULL Duplex (if I'm not mistaken.)

No, LOR uses half duplex, just like that box. A full duplex connection would use one pair for transmit and another pair for receive. LOR uses a single pair for both transmit and receive. (The other pair is used to send DC power to accessories such as the ELL, the SC485, or the RS485REP.)

Since the LOR network is a RS485 network, I say this expansion hub would work just fine.

However, it looks like expensive overkill to me. You could use a single LOR RS485 repeater to get a network with up to 4 ends. Would that be enough?

Like sias, "if I'm not mistaken" as I wasn't sure if LOR would be half or full, most items are usually full duplex or may have a half duplex setting, but recommend full duplex. So I wasn't completely sure if LOR was full duplex or not. (although I thought I had read somewhere that it was full duplex.) Be nice if that information was disclosed in the description of these RS485 units as I don't recall seeing this particular info there or even in the user manuals/specifications, but will have to go and verify that for certain.
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mike carlson wrote:

How do you get 4 ends from that LOR repeater, I see one in and only two out??

You'd have to split the 1 "in" port by wiring 2 cables. This would still be a valid RS485 network with a single line. I think the reason the repeater has 1 "in" port is that there wasn't enough room in the box for 2(?)

Paul Roberson wrote:
with the LOR repeater @ $90.00, and only two runs, for aprox $180 I can get 8 separate 4000’ runs, WOW!

I wasn't aware of the price for the hub. That's not bad.

as for power , this hub has it’s own 12 Volt power supply and will supply power to the device if hooked up..

The power on the LOR network from the controllers is about 10 volts. Someone from LOR may know if putting 12-volts on that line could damage something.
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No offense to anyone here, but I decided to contact LOR about this just to be 100% positive of what these RS485 units are, mainly because I read every bit of documentation I could readily find on the LOR site, including the data sheets and nothing said anything about this aspect.

So I thought I'd share what Kevin from LOR sent me back in an e-mail.

--------------------------------------- Kevins' Response -----------------------------------------

I was not sure of the answer but did check and was told: RS485 (EIA-485) is by definition half duplex where as RS422 is full duplex. RS485 can have only one transmitter with multiple receivers. Some documentation refers to full-duplex RS485 but that is actually just two RS485 networks run in parallel.

Light O Rama uses a single RS485 network and is thus half-duplex.

I agree that the documentation could be more detailed.

Best regards,
Kevin
---------------------------------------------------End of response------------------------------------------------------------

So from what Kevin said, and my thinking these were full duplex initially, is probably because of the last statement in Kevins' reply about an RS485 being full duplex, but only when two are placed in parallel and operated that way. Don't recall where I had read something like that, but thought I had read it somewhere.

Just thought folks would like knowing it direct from the horses mouth so to speak.

Again, no offense to anyone, and not that I didn't believe anyone here, but sometimes I just feel more comfortable knowing, and getting the facts straight from the folks that build and sell the item(s) in question.

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Kevin does not have it right either. In order to take advantage of a full duplex communication stream. All devices would need to have two pairs of connections at each device. Full duplex is not common in the devices I have worked with for data acquisition. So, if you have a device with only two terminals. How would you terminate 4 wires? In full duplex the master transmits on one pair that goes to the receivers on all devices. And all slave devices would transmit on the second pair that goes back to the masters receive terminals. In RS-485 system, Slaves do not transmit till they are talked to by the master. So, for those of you who use an input to control some aspect of your display. The input will not be recognized till the master polled that controller asking if one of the inputs has changed state. At least that is the way the ADAM modules that I work with, do it. LOR might have modified their RS-485 some so it works differently.

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Jeff Millard wrote:

rstately wrote:
garyfunk wrote:
Yeah, what Jeff said.


I must have read this a thousand times, it a thousand posts,...and it still cracks me up!


OK, I'll start stalking you... And in six months... We'll check your laugh-o-meter and see if it still reports "cracks me up!"

:)

Jeff

"It's always funny when it happens to someone else."
Just think of him as a "groupie" then it won't seem as creepy?:D
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Hi Guys..

Just to let you all know.. I have tested this RS485 8 port hub on the LOR network, put a CCR on one port, and a CTB16KD on two of the other ports.. all Unit ID found.. I did not connect the power lines as they were not needed.. Everything A ok !!

Thanks for all your replies and help..

Have a good one..
Mike..

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rstately wrote:

garyfunk wrote:
Yeah, what Jeff said.


I must have read this a thousand times, it a thousand posts,...and it still cracks me up!


Just me havng some fun. If more people lstend to Jeff when it comes to AC wiring, this would be a safer world.
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Hi Steven..

No I did not connect the ground wire, since I was not using the power connections I didn’t think I needed the ground. Maybe the ground will reduce line noise, but I believe RS485 is a balance line and grounding is not required???

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garyfunk wrote:

rstately wrote:
garyfunk wrote:
Yeah, what Jeff said.


I must have read this a thousand times, it a thousand posts,...and it still cracks me up!


Just me havng some fun. If more people lstend to Jeff when it comes to AC wiring, this would be a safer world.

But i like playing with Benders!!!
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mike carlson wrote:

Hi Steven..

No I did not connect the ground wire, since I was not using the power connections I didn’t think I needed the ground. Maybe the ground will reduce line noise, but I believe RS485 is a balance line and grounding is not required???


RS-485 is balanced voltage signalling. A tiny current is drawn in the process of sampling that voltage. This needs a return path, or over time, enough charge builds up that the two units are far enough apart in voltage that they can't read each other.

I don't remember the source, but basically, RS-485 usually works without ground, but looses a lot of reliability.. Tie those grounds together, and you should save yourself a lot of grief.. Ground is why DMX is a 3 wire cable system.
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