Netonix Forums

Hi everyone, I have 2 x WS-8-250-DC and tried mounting them at a new site. Unfortunately the switches kept getting knocked out by interference, even though the site was not a broadcast tower, although it did have a large power substation nearby, this is documented elsewhere in the forums.

Long story short, I am upgrading another site, which is DC fed, and want to try the Netonix switch again. 24vdc supply with SLA batteries. Currently the a DC-DC is in the base ensuring 24vdc output even when batteries fully charged. We have then a 40metre run of cable. Not ideal but its a site restriction, we get around a 3v drop presently, currently the Cisco SG300 10 port switch and passive POE injectors work fine, but I need more power, with the additional load, the voltage drop might be an issue, and I'm hoping the Netonix DC-Dc converter will help, effectively we move the DC-DC convertor to the top (built into the Netonix) this means the input voltage will be around 20-24vdc at the top.

The site is a critical customer serving tower, so I'm a bit nervous about installing the switch, can anyone recommend which firmware version I should be running? and any tips?

Thanks

W

At least v1.4.2 but v1.4.3rc4 has several bug fixes found in v1.4.2

If your using a large flat network start off with Discovery Protocols and Discovery Tab DISABLED. After you know everything works then enable them and if you have an issue DISABLE them and report your issue.

Also there is a known bug in v1.4.2 where if you have SMTP alerts enabled and the switch can not reach the SMTP server or the SMTP server is slow for what ever reason it messes up so start off with SMTP disabled or use v1.4.3rc4 which has this fixed.

What gauge wire are you running up the tower?

Thanks Chris, I think the cable is 1mm2. Each tower has its own management vlan and each ap has its own payload vlan. So I don't thinks its what you call flat.

I will put 1.4.2 on and see how it goes.

wisp-wand wrote:Thanks Chris, I think the cable is 1mm2. Each tower has its own management vlan and each ap has its own payload vlan. So I don't thinks its what you call flat.

I will put 1.4.2 on and see how it goes.

I would use v1.4.3rc4 as there are several bug fixes found in v1.4.2

I am not familiar with 1mm2 as a wire gauge? I think that only around 18AWG which is NOT anywhere near a heavy enough wire.

You're talking about 40 meters or 120'+ so you would need MUCH HEAVIER WIRE.

I pinged Dave on this

1mm2 is 17AWG. I know its not ideal, but its a legacy cable from my predecessor, and tricky to rerun. I will do it at some point, but making the best of what we got meantime.

wisp-wand wrote:1mm2 is 17AWG. I know its not ideal, but its a legacy cable from my predecessor, and tricky to rerun. I will do it at some point, but making the best of what we got meantime.

17 AWG is NOT enough, IT WILL NOT WORK.

The cable will heat up and the voltage will drop, will not carry enough amps.

That long of run should be MUCH heavier cable.

Hi Chris, I hear you, but it does work. Currently the DC-DC is at the bottom, and passive POE injectors at the top of the tower. It has been fine since 2014. I guess you are saying it won't work with a Netonix switch? I thought it would be better as the voltage drop would be sorted by the DC-DC convertor (in the switch) being moved to the top.

Wayne

wisp-wand wrote:Hi Chris, I hear you, but it does work. Currently the DC-DC is at the bottom, and passive POE injectors at the top of the tower. It has been fine since 2014. I guess you are saying it won't work with a Netonix switch? I thought it would be better as the voltage drop would be sorted by the DC-DC convertor (in the switch) being moved to the top.

Wayne

It has to do with AMPERAGE

You can not feed the switch on that small wire and then expect it to power several other devices all on that tiny wire.

If that was the case then your house could be powered with a Christmas Tree Extension Cord

I know what you are saying. It works as it stands though.
What would you recommend?

use below link to a handy calculator:
http://www.calculator.net/voltage-drop- ... &x=58&y=14

it is hard for me to recommend the size of wire required, as it depends on load & distance & acceptable voltage drop, and it also depends on the source supply's capability to be able to deliver enough power for instantaneous peak loads.

for example, if you use a 14AWG wire pair for power, and you load is only 120 watts, and you have 100 feet of cable, you will have a 2.5 volt loss at the load (switch in this case). That should be ok, but for example, with your 17 AWG wire, you will have a 5 volt loss at the load. And the more power you draw, obviously the greater the voltage loss.

to me, if you can run a pair of 12 AWG wire, you should be fine for all voltage ranges & loads. As soon as you use a higher AWG wire than 12, you need to get out the old calculator & figure out if you are doing it correctly or not. Obviously, cable distance makes a big difference.

Dave