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What is the pinout of the RS485 connector on a LOR?


Jim Springfield
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Jim Springfield

I want to use an Ethernet-serial converter that I have and it supports RS485 as well as RS232. It has a 25pin connector and I'd rather just create a custom cable and connect directly from that to the LOR. I can probably figure it out, but asking in case I get an answer. Also, does the LOR use 2-wire or 4-wire RS485.

thanks

--jim

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LightORamaJohn

LOR uses two-wire RS485. RJ45 jack pin 4 is A(+), 5 is B(-), don't connect any other pins.

Added: You should connect pin 6, the ground as well. Sorry that I forgot about this in the initial post.

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  • 2 weeks later...

Pin 3 is +8 or +9 volts and pin 6 is ground. I could be wrong, but I don't think you really need pin 6 unless you're also using pin 3 to power a ELL or something.

But then again, if you simply run a single pair, could that cause static build-up since the ground on the controller will "float"?

On another note, I'm using pins 1&2 and 7&8 for other things (600-ohm balanced audio signal to drive a speaker through a transformer). I found that the newer controllers, like the CTB16PC or the ELL, will pass pins 1,2,7,8 straight through, but the older CTB-08, as well as the USB-RS485 with booster did not. So I soldered 4 jumper wires from one RJ-45 to the other. Problem solved.

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  • 1 month later...

Apologies for reviving the old thread, but I am curious to know if you got this to work. Because of the location of my controller in regards to my PC, I want to use a similar setup. What serial-to-ethernet converter are you using? I have a Lantronix UDS1100 that can be setup to use RS232 or RS422/485. I have already tried this configuration:

PC--->Router--->Lantronix(through a supplied 25-to-9 pin cable)--->SC485--->CTB-16KV6

It did not work. The converter comes with software to assign a COM port to the converter's IP address. I can see by the LEDs on the converter that the HU is attempting to establish communication, but the controller just isn't seeing it. Would I be better off trying to bypass the SC485 and just go from the converter's 485 pins to the controller? If anybody else has done a setup like this, would you be willing to share how it's done?

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Someone who knows more about the LOR protocol will know for sure, but I would guess that your biggest problem with this setup will be timing. The Lantronix hardware/driver probably sends the data a byte at a time, which may mess up the timing between bytes.

But again, this is a guess.

In answer to your other question, I think you would have better results if you take the SC485 out if the circuit, since the UDS1100 supports 2-wire RS485, which is what the LOR controllers use.

Reading the UDS1100 documentation, it seems that pin 7 (ground) connects to pin 6 on the LOR RJ45 jack; pin 14 goes to pin 4; and pin 15 goes to pin 5.

If the Lantronix turns out to not work, here's another idea: Since it appears the reason you want to use this configuration is that you don't have a spare cable between your PC and the LOR controller, you can make use of the existing 100baseT cable. Unless you're using Gigabit networking (1000baseT), your network cable is only using two of the 4 pairs. You could pull out the other two pairs and use them for your LOR network.

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I have no idea what the "Lantronics" is... but it sounds like you're trying to plug LOR controllers (indirectly) into a router?

You don't want to do that...

LOR controllers use ethernet-like cabling, but they do NOT speak IP/Ethernet and you do NOT want to plug them into a router. You plug them into a 485 converter ("dongle") which goes either to a serial port or USB port, depending on the dongle.

Sorry for "shouting" if that wasn't your intent. Just wanted to make sure you didn't damage something really bad...

-Tim

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Tim Fischer wrote:

I have no idea what the "Lantronics" is... but it sounds like you're trying to plug LOR controllers (indirectly) into a router?
Not exactly. He wants to plug the LOR controller into what is basically a mini terminal server. Here's the link: http://www.lantronix.com/device-networking/external-device-servers/uds1100.html

This device speaks TCP/IP on it's network port; and a choice of serial protocols, including RS485, which is exactly what LOR uses, on it's serial port. Assuming everything is connected correctly, there is no danger of damaging anything.

It will be interesting to hear if this actually works.
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Steven wrote:

Not exactly. He wants to plug the LOR controller into what is basically a mini terminal server. Here's the link: http://www.lantronix.com/device-networking/external-device-servers/uds1100.html

This device speaks TCP/IP on it's network port; and a choice of serial protocols, including RS485, which is exactly what LOR uses, on it's serial port. Assuming everything is connected correctly, there is no danger of damaging anything.


Gotcha.

People in the past have assumed you could plug an LOR controller right into your network jack, so I was just making sure... (Dan once said people have even plugged them into a live phone line and destroyed them...)

-Tim
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Tim Fischer wrote:

People in the past have assumed you could plug an LOR controller right into your network jack, so I was just making sure... (Dan once said people have even plugged them into a live phone line and destroyed them...)
Plugging it into a phone line would put ~48 volts directly across the RS485 line. I can see that would be bad.

Plugging it into a network jack (10 or 100) would put 9 volts from the LOR controller on the Rx pair. This could potentially destroy a low quality router/switch.
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Well, after much trial and tribulation, I have not had any luck getting this to work. It looks as if the "heartbeat" that the software is sending out is getting to the converter, but not to the controller. The activity LEDs on the converter are blinking ferociously, showing me that it is receiving the data, but the status LED on the controller continues to blink. There are some settings in the Lantronix I can play around with, but like mentioned earlier, there may be an issue with the timing that is preventing successful communication. Dan had mentioned to me in an e-mail that he had heard of some people who had gotten a setup similar to this to work. Gosh, I wish I knew how they did it. :{

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LightORamaDan

Do you have to set the baud rate on this thing? Is it bi directional... Does it automatically turn around? RS485 is half duplex and the device has to be smart enough to change direction on its own.

Also you mentioned that the led was blinking alot ... The heartbeat is a couple times a second pulse.

Dan

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Hi, Dan.

The baud rate is selectable in the setup screen. I left it at 9600, 8bit, no parity; no flow control. It says it supports 2 or 4 wire RS485, so i'm assuming it is half duplex in 2-wire mode. There are some settings for passive and/or active connections on the serial port. I played around with these settings and had no luck yet. If anyone wants to take a look at the user guide, here it is:

http://www.lantronix.com/pdf/UDS1100-IAP_UG.pdf

I'm open to suggestions. :)

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LightORamaDan

The hardware utilty runs at 19,200 (unless ELLs are attached). The Show Player and Sequence Editor use the baud rate as set in the Sequence Editor in the Edit->Preferences->Network Preferences.... From left to right the speeds are: 19.2 , 57.6 and 115.4

8 bit, 1 start bit, 1 stop bit, no parity

Dan

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Eureka! It works! Seems that's all it needed was for the baud rate to be matched to the software. Works like a champ now. Wow, theoretically, now I can work on sequences at work and run them on the controller at home. Well...if the boss isn't around anyway. LOL For those of you curious to know, the Lantronix device server isn't cheap, about $180 or so. I also had to make my own custom 25-pin to RJ-45 cable, but those were parts I had lying around at work. But, if you're like me and running a really long patch cord from your computer to the controller isn't going to be an easy task and you have a router or network switch in the vicinity of your controller, this is the way to go. Took some tinkering, but it paid off.

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FireMedic4Christ

Steven wrote:

On another note, I'm using pins 1&2 and 7&8 for other things (600-ohm balanced audio signal to drive a speaker through a transformer). I found that the newer controllers, like the CTB16PC or the ELL, will pass pins 1,2,7,8 straight through, but the older CTB-08, as well as the USB-RS485 with booster did not. So I soldered 4 jumper wires from one RJ-45 to the other. Problem solved.


To clarify the other note in your reply:

You are using pins 1,2,7,8 to send an audio signal. To make sure I understand correctly, I can modify the Cat5 at my USB485 and route my audio output from the computer to these wires.

Thank-you
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FireMedic4Christ wrote:

To clarify the other note in your reply:

You are using pins 1,2,7,8 to send an audio signal. To make sure I understand correctly, I can modify the Cat5 at my USB485 and route my audio output from the computer to these wires.

Actually, I am just using pins 1 and 2. My USB485 is plugged into two Cat5 cables: One for the left side of the yard and one for the right. I send the left audio channel through pins 1 and 2 of the Cat5 cable that goes to the left side of the yard and the right audio channel through pins 1 and 2 of the Cat5 cable that goes to the right.
I sliced the insulation of the Cat5 cable before the RJ45 jack and pulled the orange/white pair.

You could wire this pair of wires directly to your computer speaker outputs, but I didn't do this because I was concerned that the resistance of the long run of wire would attenuate the signal passed to the 8-ohm speaker. My 100-foot run of Cat5 cable would be 200-feet of 24-gauge wire. The resistance of this is about 6 ohms, which would significantly attenuate the signal, especially the higher frequencies, because a speaker's impedence at higher frequencies is lower.

So instead of hooking it up to the speaker directly, I used an audio transformer at each end to change the impedence from 8-ohms to 1000-ohms. I also used a small 2-watt audio amplifier because the output from the computer was not enough. The result is a nice sound that can be heard a hundred feet away, but isn't too loud for the neighbors.
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