Good quality cable needed

[NickMu]

Thank you again Norm.
The total cable length is about 150’.
Wireless is not an option due to the fact that the remote module (slave) will, at some point, be submerged and a 100 % reliable connection is a must.
The cable you suggested fits some of the requirements but I’m looking for only one twisted pair and two power wires. Heavy duty jacket and shielding are a must along with availability in large quantities with no lead time. I will be employing half duplex communication using a custom protocol.

I can not express enough how much I appreciate your help.

I might have to contact some of the major cable manufacturers for some help but I tried the forum first hopping that someone might already be using something like this and knowing that is nothing I can do until after the weekend.

Regards,

Nick

[Normnet]

For 150' could the cable be enclosed by a continuous length of black plastic flexible pipe?

Norm

[dhouston]

http://www.hyperline.com/catalog/cab...sf4-a-pe.shtml

[NickMu]

Hi Norm,

I need a bending radius on a few inches. The cable will be protected by mesh sleeving to preserve flexibility and add more toughness to it.
This project of mine is in its infant stage. I’m sorry that I did not take the time to fully explain the requirements but I myself don’t have all the information yet. I’m collecting all the information I can before committing to a final design approach.

The RS485 half-duplex and maximum 4 wires cable (power + twisted pair) is already decided and can not be changed.

I found a good (but not ideal) Belden cable 3106Aas a candidate. Its only problem is that does not give me a separate GND wire.

Dave,
Your suggested cable seems robust enough.
I only have one question: can one of the twisted pair be used for power transfer to the slave unit? I was told that the data wires should be twisted and power wires should be normal.

Thanks for the input.

Nick

[dhouston]

Dave,
Your suggested cable seems robust enough.
I only have one question: can one of the twisted pair be used for power transfer to the slave unit? I was told that the data wires should be twisted and power wires should be normal.

I've never seen a requirement that the power pair be non-twisted and doubt that twisted pair would cause a problem.

I found it merely by searching Bing using 'rs485 cable power shield waterproof' so your questions would best be addressed to the supplier.

Since you only need half-duplex, this should cost a bit less.
http://www.hyperline.com/catalog/cab...sf2-a-pe.shtml

[NickMu]

I was targeting the same one after you gave me the link.
I will contact the manufacturer for more information and get back with my findings.

Thank you again Norm and Dave for your prompt responses.

Nick

[Normnet]

I have been sending power along with RS485 for several years on CAT5 (twisted) with no problem at a baud rate of 300 although that may make no difference.

Norm