Extending RS232 over long distances

[jderou]

Our older Haas mill and lathe have a serial interface for loading programs. The machines will be a pretty long way from my desk (probably 200ft). What is the best way to do this? I found this:
http://www.minicom.com/ads/kvm_232.h...FQllQQod_BU6MQ
but I'm not sure if this is the way to go, or if its the cheapest solution.
thanks for any help.

Joe

[Geof]

Look up gar in the members list and pm him. He has a solution.

[ninefinger]

check out this site / product

http://www.bb-elec.com
http://www.bb-elec.com/bb-elec/liter...op4-3903ds.pdf

2 reasons to for this one - protects the card in the mill which will cost $$ to replace if it gets zapped and the external power source means that you don't need to worry about a PC or laptop with a low power port messing up communications.

Mike

[dcapps4140]

Go wireless. With the proliferation of cheap pc's and peripherals it is the best way to go. We use it every day here at our shop.

[dave@eew]

I still have one machine in the shop that is linked with a 232 port and I send it over with a short-haul modem. It has both sides protected.

[kerino]

You might want to look at a fibre optic solution, as it is immune to emf interference.

[jderou]

Originally Posted by Geof Look up gar in the members list and pm him. He has a solution.

I checked out his website, looks like a good/inexpensive solution. Wonder if you can put a hub in the cat5 and split it to two machines? I'll probably get in touch with him in the next couple weeks, when we get ready to move the machines.

check out this site / product http://www.bb-elec.com http://www.bb-elec.com/bb-elec/liter...op4-3903ds.pdf 2 reasons to for this one - protects the card in the mill which will cost $$ to replace if it gets zapped and the external power source means that you don't need to worry about a PC or laptop with a low power port messing up communications. Mike.

Is the second link you posted the isolating repeater, or is it just an isolator? It says it can extend the range beyond 50ft, but it doesn't say how far beyond 50ft.

Go wireless. With the proliferation of cheap pc's and peripherals it is the best way to go. We use it every day here at our shop.

Wireless RS232??

I still have one machine in the shop that is linked with a 232 port and I send it over with a short-haul modem. It has both sides protected.

I did a bit of searching on short-haul modems, they seem to be a similar device to gar's solution here: http://www.beta-a2.com/
correct me if I am wrong.

You might want to look at a fibre optic solution, as it is immune to emf interference.

Do you know of any sources for this?

Thanks for the info, obviously their are several options.

Joe

[Death Adder]

I am surprised that no one has mentioned RS422/RSS485 yet! It's the simplest, easiest solution to the problem and it can be done cheaply too. Just google or look on ebay for RS232 -> RS485 adapters. RS485 has a very long range. Why waste your time and money with CAT5/FIBER/ETC if cheap $10 adapters will do what you want. I can't promise that it perfectly fits the desired application here but it's worth looking into I'd think.

[Sharknose]

For a cable run of 200 ft. you may not need to use any extra devices, if you use well shielded, low capacitance cable, and aren't trying to run faster than 9600 baud. Best I've seen is 12.5 pF/ft. But if you've got to run up to the ceiling then 100 ft. one way, and 175 ft. at a right angle to that, and then down from the ceiling, your cable is maybe 315 ft. long. Even with good cable, that'd probably limit you to 4800 baud.

[PolyPill]

I've been looking at wireless solutions to do budget race car engine monitoring from the pit and I found a few things that work for less than $200.

You can get a serial to bluetooth converter then a pair of bluetooth antennas.

There are also serial over ethernet boxes, which can be combined with wireless 802.11 if you need an even greater range.

[jderou]

wow, lot of info. Sharknose that is a point well taken as I am not sure where the office is going to be yet. We are moving the machines to a new building, and the Pointy-Headed-Types (sorry, I had to steal that from another post) aren't sure where to put the office based on that cable length problem. Obviously now we can put it anywhere we want, as we have plenty of options.

[mcnerney]

Joe

Another option that you might consider is the mini line driver with isolation from Black Box. They are $98 each (need one on each end). It comes with a standard RJ12 telephone jack on one side and a DB25 connector on the other end. Works on regular telephone wire (19 to 26 awg) out to 15K ft. Note the minicom device you pointed out requires Cat 5 cable, but in your case your only going 200 ft so that shouldn't be an issue.
http://www.blackbox.com/Catalog/Deta...,1465&mid=1130

Larry