cables type for DeviceNet

[CX_Luigi 1]

i have to wire a DeviceNet network and customer propose to use CAT5 for connections in lieu of usual Belden cable, mainly for time reason (that is, CAT5 is readily available at the moment at the site). It is advisable and/or safe to use such a cable? Total network length is around 120-160 meters. Also since there are total 6 panels with assorted I/O inside, is it possible to use each panel power supply for powering communication and modules instead of daisychaining all modules with same supply starting from DRM?

[scottmurphy 1]

The first question I would ask, especially when it comes to Devicenet, is, does it say you can/cannot use CAT5 connections in the installation documentation? Of all the devicenet installations that I have done, I doubt that the cable could be made off correctly into these connections, on that basis, I would say no. To save time is false economy vs doing it properly to begin with, you will more than likely spend more time troubleshooting bad connections. Just my 2c

[PMCR 66]

I agree with Scott. I would strongly suggest using the correct DeviceNet cable. Proper shielding and grounding are very important in DeviceNet. Cat 5 / Cat 6 offers neither grouding or shielding. Also, Cat5/Cat6 is a twisted media, creating different impediance charactersitics from DeviceNet cable, which is a non-twisted cable of higher gauge (larger wire diameter). As Scott said, If you try using Cat5, you will most likely end up replacing with DeviceNet Thin Net cable in the end.

[BobB 58]

I would strongly suggest you go to www.odva.org and download some information on how to set up and wire a Device Net network. I would not even think about using CAT 5 - it would be useless and you would only finish up re-wiring anyway particularly over that distance. I would be using thick Device Net cable for that length of run. It is recommended that the same power supply be used - not separate ones - and the power be joined into the middle of the loop. Device Net will stop working if the voltage drop over the network exceeds the recommended levels.

[CX_Luigi 1]

thanks anyone for their reply. I went to ODVA site and downloaded cable spec, and will not accept customer's choice of connections.

[René Heijma 1]

I saw you already made the right choice but still one simple answer. Don't use CAT5! Rules are: Up to 100m at any baudrate you can use thin DeviceNet cable. Above 100m it is always thick DeviceNet cable. You are talking control and you do not want to waste time during commissioning fighting a flacky network.