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Serious controller issues


cetacea

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Well I don't have one of those, maybe I should go out and get one. I spent all day installing new connectors on every single cable and then making new cables today and they still don't work. I'm wondering if there is something wrong with my crimper. They look perfectly fine when I'm done with them, but LOR sure doesn't like them.

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John,

If he was making crossover cables. Then nothing would work at all. Now if he is splitting a pair, that would have some effect on picking up noise.

OP, I have a question for you. You sound like someone that knows something about making Ethernet cables. So, this is not meant to be a question to insult you, but just to cover all angles. You are splitting a pair between pins 3 and 6, right? Not putting the wires like this are you? 1 pair pins 1 & 2, 2nd pair on pins 3 & 4, 3rd pair on pins 5 & 6, and 4th pair on pins 7 & 8? That would be the wrong way and would produce the split pairs. This would allow noise to develop on pins 3 & 6. And at this minute I am not sure if that is the Rx pair or Tx pair for the controllers.

Dang this sure does sound like a hum dinger. But sounds like you are getting close.

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Well this is how I'm doing it which is how I have always done it (not saying it is right):

Pin 1 and 2: striped blue and solid blue
Pin 3 and 4: solid orange and striped orange
Pin 5 and 6: striped green and solid green
Pin 7 and 8: striped brown and solid brown


That is how the picture shows it on the back of my crimper.


In reality, does it really matter as long as both ends are the same? I guess in answer to your question, I do not split a pair and perhaps I should?

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cetacea wrote:

In reality, does it really matter as long as both ends are the same?

Yes, it does matter. The LOR network puts data on "pair 1", which is pins 4 and 5.
It puts power and ground on "pair 2", which is pins 3 and 6.

A Cat5 cable has 4 twisted pairs. In the way you wired the cable, you have the network (pins 4 and 5) split between 2 twisted pairs, the green pair and the orange pair. This could make a difference over 50 feet, because the power on pins 3 and 6 may be slightly "dirty", and thus could affect the network.

I would cut the connectors off both ends, and re-crimp them according to TIA-568.
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cetacea wrote:

Well this is how I'm doing it which is how I have always done it (not saying it is right):


TIA-568B is the de facto standard for network wiring. The correct pinout is:

Pin 1 and 2:orange/white - orange
Pin 3 and 4: green/white - blue
Pin 5 and 6: blue/white - green
Pin 7 and 8: brown/white - brown

Pin 1 is on the first pin on the left when the gold contacts are face up.
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Ok thanks everyone, I am going to go through and redo all my cables tomorrow. I'll let you know if that fixes the problem. I am keeping my fingers crossed because I don't know what else it could be.

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Steven wrote:

cetacea wrote:
In reality, does it really matter as long as both ends are the same?

Yes, it does matter. The LOR network puts data on "pair 1", which is pins 4 and 5.
It puts power and ground on "pair 2", which is pins 3 and 6.

A Cat5 cable has 4 twisted pairs. In the way you wired the cable, you have the network (pins 4 and 5) split between 2 twisted pairs, the green pair and the orange pair. This could make a difference over 50 feet, because the power on pins 3 and 6 may be slightly "dirty", and thus could affect the network.

I would cut the connectors off both ends, and re-crimp them according to TIA-568.


I would have to agree with cetacea, it doesn't matter, as long as the other end is wired the same. Let's take for instance that I were to connect the blue/white and white/blue to connectors 1 & 2 on both ends. Now if I took a green marker and changed the color, did that change the wiring any? No, the same two wires are still attached to the same connection points on the connector.

MikeH
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MikeH wrote:

Steven wrote:
cetacea wrote:
In reality, does it really matter as long as both ends are the same?

Yes, it does matter.  The LOR network puts data on "pair 1", which is pins 4 and 5.
It puts power and ground on "pair 2", which is pins 3 and 6.

A Cat5 cable has 4 twisted pairs.  In the way you wired the cable, you have the network (pins 4 and 5) split between 2 twisted pairs, the green pair and the orange pair.  This could make a difference over 50 feet, because the power on pins 3 and 6 may be slightly "dirty", and thus could affect the network.

I would cut the connectors off both ends, and re-crimp them according to TIA-568.


I would have to agree with cetacea, it doesn't matter, as long as the other end is wired the same. Let's take for instance that I were to connect the blue/white and white/blue to connectors 1 & 2 on both ends. Now if I took a green marker and changed the color, did that change the wiring any? No, the same two wires are still attached to the same connection points on the connector.

MikeH


But changing the colors does not alter which wires are twisted together. And that is important.. 4&5 are twisted together, which has two effects. One is that if they are used for differential signaling, or a current loop, they radiate less energy into adjacent conductors, because they alternate which one is closer, and thus they alternate which one is sending the most signal to adjacent conductors. If they are passing opposite voltages or currents, then it balances out.

The one that is important for LOR is that for rejecting signals from adjacent noise sources. Again, with the twisted pairs doing the signaling, they alternate which one is closest to the noise source. If they were not twisted, one of them would be closer to the source, and pick up more stray voltage, possibly obscuring the desired signal. With them alternating, they take equal turns picking up signal. So both wires may gain a half volt, or even a few volts of stray signal. But because the receiving chip is not looking at the absolute voltage to ground, but rather which wire has the higher voltage, the twisted pairing creates a large degree of immunity from electrical noise.
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On another note about the twisted pairs being used together. Very true that the twist aids in rejectioning noise. I think just as important. If you have a split pair and in the case of LOR those other pins pass thru the connectors to the other boards....and are UNTERMINATED to any source. So they act like an antenna collecting noise and putting it next to a signal wire.

Basially in LOR the 485 is a diferential signal. The receive and transmit are on the same pair of wires and the electronics flip flop. In ethernet (computer) there is a transmit pair and a receive pair.

Chuck

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Thanks Chuck,

yes you are right, in RS-485 the TX and RX are on the same pair. Getting old at 52 and sometimes I forget to keep this Ethernet and RS-485 on the same cable, yet separate information or specs so to speak.

MikeH,
I hope that when the op has changed his connections, that will fix the problem and I hope that you take note of it. It appears that you are still young in the ways of electronics. Much you to learn padawan, umm.

OP,
Yes, please get back on here let us know if this fixes the problem. Also I will second what Steven was saying about a termination resistor in the open RJ-45 socket on the last controller. Install this resistor in a plug and then plug it into the socket. If everyone would read the white papers dealing with RS-485 communication. Then we all would see that it is recommended that a terminating resistor be used at the ends of the network. It is possible that the signal from the adapter could bounce or echo off of the end of the network and as it bounces back, it becomes a noise source that blocks or garbles the command from the computer. So, this would be the next recommend step if the connector issue does not fix your problem.

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Max-Paul wrote:

Thanks Chuck,

yes you are right, in RS-485 the TX and RX are on the same pair. Getting old at 52 and sometimes I forget to keep this Ethernet and RS-485 on the same cable, yet separate information or specs so to speak.

MikeH,
I hope that when the op has changed his connections, that will fix the problem and I hope that you take note of it. It appears that you are still young in the ways of electronics. Much you to learn padawan, umm.

OP,
Yes, please get back on here let us know if this fixes the problem. Also I will second what Steven was saying about a termination resistor in the open RJ-45 socket on the last controller. Install this resistor in a plug and then plug it into the socket. If everyone would read the white papers dealing with RS-485 communication. Then we all would see that it is recommended that a terminating resistor be used at the ends of the network. It is possible that the signal from the adapter could bounce or echo off of the end of the network and as it bounces back, it becomes a noise source that blocks or garbles the command from the computer. So, this would be the next recommend step if the connector issue does not fix your problem.

I stand corrected. I was referring only to the way the connectors would be the same on each end. I, of course neglected to read the part where LOR uses a different scheme. To that, I say, be sure to read proper documetation.
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I just want to thank everyone here, my issues are solved! I replaced every single connector today and put them on the correct way. I ran the hardware utility and every controller worked perfectly. The display is running now and it is flawless! I have had these issues for 3 years now and they are finally fixed.

Thanks everyone for your help with troubleshooting my comm issues. I am very happy!

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