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Does LOR network REQUIRE them to be daisy chained?


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Posted

I know in a normal LOR network, you come out of the RS485 adapter to your first controller, then daisy chain using cat5 to the other controllers.  What I'm asking is, is this required?  Can you come out of the RS485 adapter into a switch and then run the controllers from that switch?  Or is there a protocol being sent down the line that won't be "forwarded" through a normal network switch.

The only reason I ask this is based on location of the boxes, I was trying to avoid having cat5 cables going back and forth all over the place where I could easily have one centralized location that the cables run to.

I should know this answer but I haven't seen it, and almost all diagrams show a LOR network in a daisy chain type environment.

Thanks!

 

 

Posted

If you are using regular controllers, all using LOR protocol, then you have no other choice. This isn't ethernet TCP/IP you are dealing with. It's RS485. 100% different technology than ethernet.

Now, if you are using E1.31, or similar, then it's a different answer.

Posted

Thanks Don!  I figured the RS485 adapter was "converting" the required signal to a TCP/IP compliant protocol and then the boxes where changing it back to the LOR protocol.

 

None the less, good information to know so I can plan my yard design with that in mind.

Posted

Nope. No conversion. If you are using a RS485, then it's all RS485 protocol.

Posted

RS 485 is more like  RS 232 on Steroids. and a College degree

Disclaimer: I have not tried this with LOR

I have installed other RS 485 stuff using http://www.elkproducts.com/product-catalog/elk-m1dbhr-m1-data-bus-hub-for-retrofit allows a Star configuration for RS485 security components. 2 of the 4 output terminal leads are +12 and Ground (and can be ignored) But you mist INPUT those to power the board

One note: Elk expects the line to be terminated at the furthest end (120 ohms), I noticed that LOR makes no requirement on the user  to set a terminator.?? Auto Termination?

 

Posted
1 minute ago, TheDucks said:

One note: Elk expects the line to be terminated at the furthest end (120 ohms), I noticed that LOR makes no requirement on the user  to set a terminator.?? Auto Termination?

The RS-485 spec includes 120 ohm termination at both ends of the circuit.  As a general rule of thumb, our networks are simple enough that we get away without terminations.  That does not mean that they should not be included.  However in the event of what appears to be network problems, one of the first things to try should be terminations.  As we put more devices on the network and run at higher speeds, terminations will become more of a requirement.  Personally I terminate all three of my LOR networks.  And no, the LOR controllers do not have auto termination.

 

Posted
8 hours ago, k6ccc said:

The RS-485 spec includes 120 ohm termination at both ends of the circuit.  As a general rule of thumb, our networks are simple enough that we get away without terminations.  That does not mean that they should not be included.  However in the event of what appears to be network problems, one of the first things to try should be terminations.  As we put more devices on the network and run at higher speeds, terminations will become more of a requirement.  Personally I terminate all three of my LOR networks.  And no, the LOR controllers do not have auto termination.

All the RS-485 devices I had worked with had a Jumper you removed if it was not at the end. Even the 'controller 'had a jumper in case it was not at the end.  I also use (1/w resistor in a RJ45 plug as) termination.

 

  • 4 months later...
Posted (edited)

Just so everyone understands the 2 outputs.... this configuration CAN be used as if the dongle is in the middle of the cable (as in  say, 3 controllers on one port and 2 on the other,  (even odd, whatever) the terminators would then go at the farthest boxes one on each end of the ENTIRE cable length. Terminators... RS-485 is NOT, rs-232, 232 uses make break technology, where as 485 uses differential signalling (totally different topology and method).

485 is like two ropes hanging between 2 sets of trees... both ropes side by side... go to one end of the pair... tap one to create a signal on that one that travels down the rope to the other end and returns. now while tapping that one, start tapping the other one also.. the difference in the arrival time of the bounces in the ropes at the other end is the "Data", the reflections are exactly that....unwanted reflections, terminators inhibit the bounce back of the reflection. NO it is NOT wise to try and make a third cable  or a "tap" off the length somewhere else as it would add MORE reflections.

RS-485 used correctly... is a VERY reliable system.

Edited by a31ford
spelling
Posted
19 minutes ago, a31ford said:

Just so everyone understands the 2 outputs.... this configuration CAN be used as if the dongle is in the middle of the cable (as in  say, 3 controllers on one port and 2 on the other,  (even odd, whatever) the terminators would then go at the farthest boxes one on each end of the ENTIRE cable length. Terminators... RS-485 is NOT, rs-232, 232 uses make break technology, where as 485 uses differential signalling (totally different topology and method).

485 is like two ropes hanging between 2 sets of trees... both ropes side by side... go to one end of the pair... tap one to create a signal on that one that travels down the rope to the other end and returns. now while tapping that one, start tapping the other one also.. the difference in the arrival time of the bounces in the ropes at the other end is the "Data", the reflections are exactly that....unwanted reflections, terminators inhibit the bounce back of the reflection. NO it is NOT wise to try and make a third cable  or a "tap" off the length somewhere else as it would add MORE reflections.

RS-485 used correctly... is a VERY reliable system.

Seconded that a properly terminated RS485 is very robust.

LOR is not very clear on whether this is 2 jacks on a single driver (as you suggest), or 2 drivers, each capable of 4000'

A few 'typical use diagrams are wort many words :)

  • Like 1
Posted (edited)

Technically you can do it with a single port dongle also..(this is NOT complex, but does take cabling understanding).

IN 485 topology, the 2 final ends of the cable should have a 120 Ohm resistor (1/4 watt is fine) (2 resistors total, one each end).

if you keep your connections close on an adapter cable you can make up a terminator stubby for each end (instead of dedicating an entire cable to it), the stubby consists of both a male and a female CAT5 connector with a short length of cable between them (2 to 3 inches). in the female connector you can place the 120 ohm resistor across pins 4 and 5 (the data set) and hot glue the exposed wires & backside pins like this  notice the resistors near the cable under the coating of hot glue.

PC150005_zps3e92a203.jpg

these would go to the "Far ends of the cable(s) NOW, here's the trick, make a 3rd stubby (NO resistors, BUT add a 2nd female jack, and wire all of it pin to pin (1 to 1 to 1, 2 to 2 to 2, 3 to 3 to 3, and so on, keep ALL the cables as short as practical, as to not cause reflections. you would use the mutant cable as follows: the male would plug into  the dongle, the females would go to the "Through cables" on to the first controller on each of these cables, from  there, it's daisy chain all your boxes as normal 3 on one cable 2 on the other (even, odd, whatever) the LAST box on each run, gets the terminator stuby as the photo above, the cable into the female, the male into the last box's input...

Edited by a31ford
Posted
16 minutes ago, TheDucks said:

Seconded that a properly terminated RS485 is very robust.

LOR is not very clear on whether this is 2 jacks on a single driver (as you suggest), or 2 drivers, each capable of 4000'

A few 'typical use diagrams are wort many words :)

I had the photo of the stubby's up on photo bucket, and for sure I second your comment  "A few 'typical use diagrams are wort many words"

If I get a second tomorrow, I'll draw some diagrams and edit the post above.

Thanks for the input & support !!

Posted
50 minutes ago, a31ford said:

Technically you can do it with a single port dongle also..(this is NOT complex, but does take cabling understanding).e "Far ends of the cable(s) NOW, here's the trick, make a 3rd stubby (NO resistors, BUT add a 2nd female jack, and wire all of it pin to pin (1 to 1 to 1, 2 to 2 to 2, 3 to 3 to 3, and so on, keep ALL the cables as short as practical, as to not cause reflections. you would use the mutant cable as follows: the male would plug into  the dongle, the females would go to the "Through cables" on to the first controller on each of these cables, from  there, it's daisy chain all your boxes as normal 3 on one cable 2 on the other (even, odd, whatever) the LAST box on each run, gets the terminator stuby as the photo above, the cable into the female, the male into the last box's input...

Or buy it ready made http://www.pctekonline.com/pccarjsninff.html

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