Max. distance for RS - 232

[5 AX]

I have been told by my IT guy that I can only go 75 feet before I lose signal. Is this accurate? I know I have had longer runs at previous jobs.

[Guest]

Well I can tell you we here go a little more than 100 and we have never and any issue with signal loss. We run off of the DNC at times an as of yet have not had a problem.

 

Now one place I worked at years ago, they ran their cables a little to close to the flurosant(sp) lights and we suffered occasional dropouts there.

 

HTH

[gavetta]

I've heard something like that before but not sure how long is too long. I remember reading some where that shorter is better and that there is a point where data may be lost. If I can find the info I'll post it. Sorry that this isn't specific help but thought you should know that yes it can be an issue.

[?Mark]

If you use good shielded cable like the one from Predator "Grizzly" you should be good for a longer distance. I heard 200 feet is not a problem.

 

Mark

[crazy^millman]

Yeha I have seen over 300' problem is the baud rate has to drop quite a but for every long distance. I would look at dropping $200-300 on a PC and put it right next to the machine and be done with. Then you could run max baud rate and not worry about dropped lines or code.

 

 

HTH

[5 AX]

Thanks for the reply, I thought it wouldn't be problem. I am only going between 100 and 150 feet.

[chris m]

I'm running 19200 with over 100' no probs but I do have some expensive cable helping me out

 

C

[toolsman]

We have had up to near 200 feet with no problems with a good cable. We did move a cable away from an overhead crane that caused us to drop carrier sometimes, but not a problem since.

 

Neil

[Rick46]

found some info on this page about RS 232 lengths.. interesting reads.. might give you some general idea on lenghts and baud rates to use...

 

 

http://www.vutrax.co.uk/rs232.htm

[cadcam]

Make sure you use good cableing like Grizly cables.

 

http://www.shopfloorautomations.com/cabling.php

[BernieT]

Be carefull of EDM's running nearby, they can cause RS232 probs.

[Rick46]

EMI Electro Magnetic Interferance.. same can be cause by flourecent lighting...

[Tom Szelag]

Yea definately get good, shielded cable. You can have some squirrely business go down if you pick up interference running DNC.

[jbjim]

It depends! If you running in a "clean RF location" vs a "noisy location". It also depends on baud rate, type of handshaking or protocol. In some environments you can get 200+ feet. In others you might struggle to get 76 feet. Use high quality shielded serial cable, and make sure you have both ends grounded. Where you can get into trouble is where the computer and machine controller are using different grounds. This creates a "ground loop" (bad), which acts as an antenna and makes a nasty mess out of data transmission. The 75 foot number is where the square digital (on/off) signal pulse starts bending into a sinusoidal (like analog audio) waveform. Depending on baud rate (speed) the bit spacing varies proportionally. When the controller or computer can't discern a zero or one bit.....you are hosed.

[K Reed]

hehe..watch for High frequency tig welding too. We can't DNC if we need to put a spot of weld on something because of the high frequency start. Aluminum welding around Rs-232 is a big no go!

[cblythe3d]

Just for grins

 

With good common grounding (no ground loop) on a bet, I got 200 feet, 9600 baud (.01 delay) with 2 wire speaker cable. NOT RECOMMENDED

 

For short runs in a EMF clean environment (no arc or spot welding or electrical switching equipment)at lower baud rates 99 cent store phone cable works fine.

 

But with modern CNC and high density code, for reliable high speed communication fully sheilded, no ground loop high quality cable connection is the minimum. Signal boosters may help on longer runs, however the old computer next to the machine suggestion, networked is 100% and essentially free as even kids wont touch old processors.

 

Quit drinking: easy done it thousands of times

C.B.