Can any clever person tell me whether they would use cat5 cable on an RS 485 network??

The runs are not particularly long (typically 25m between devices) but it is in a crowded computer room.

Thanks

Dave

Its ok for camera telemetry, whats it for?

technically its ok but as its solid core it isnt designed for our terminals. Is used prefer not to but i dont see a real technical reason (the twists are right) apart from it not being screened but technically a balanced 485 shouldnt need screening anyway (i said 'technically' guys)

Can any clever person tell me whether they would use cat5 cable on an RS 485 network??

The runs are not particularly long (typically 25m between devices) but it is in a crowded computer room.

Thanks

Dave

For RS-485 the terminating resistors have to match the cable impedance, so you might cause problems unless you get them both right.

Read this: http://www.maxim-ic.com/appnotes.cfm?appno...63&CMP=WP-1

Edited January 4, 200719 yr by amateurandy

lol andy, i have been saying this for years but apparantly the laws of rs485 only apply to galaxys not texecoms

Well....

Its being used for a small BMS system to monitor room temp and humidity stats, and a lot of volt free contacts, we are also picking up some display meters using modbus.

We were goiing to use a two pair twisted individually screened cable but the main contractor has now supplied cat 5 cable and I was just trying to head off any forseeable problems.... thanks

youe be fine but dont put multiple buses in the same cat 5, that will probably cause you grief unless your resistors are spot on

youe be fine but dont put multiple buses in the same cat 5, that will probably cause you grief unless your resistors are spot on

Top man......... we'll see what happens then.

Thanks

We recommend it.

Ours is a full duplex (two channel, four core) RS485 bus which runs at over 100kbaud. We have tested it extensively, and it works over 1,000m with Net2. Having said that, all systems are different in the way in which they cope with data errors, so trying it is good.

A useful tip is to connect spare pairs in the CAT5 cable as if they were a screen. That is a very effective method for reducing interferance.

We recommend it.

Ours is a full duplex (two channel, four core) RS485 bus which runs at over 100kbaud. We have tested it extensively, and it works over 1,000m with Net2. Having said that, all systems are different in the way in which they cope with data errors, so trying it is good.

A useful tip is to connect spare pairs in the CAT5 cable as if they were a screen. That is a very effective method for reducing interferance.

drew,,,, a top tip that I will be sure to remember.... thanks