Location of network interface (5500CN)

I'm considering adding a network interface (5500CN) to my c-bus system.

I have two options for the location:

1. In the c-bus switchboard
2. In the WIR, where the network switch is

A couple of questions:

1. Is there an alternative power supply to the plug pack?
2. Does the network interface need to be connected to a relay/dimmer or can it be connected to the closest switch?

 

Hey Matthew,

As far as placement of the CNI is concerned, either location that you have proposed would be fine, although I would lean towards your WIR, as the blue insulation (or any other color for that matter) of standard Cat5e/Cat6 data cabling is NOT mains(240v) rated, and it might be best to keep it out of your main switchboard to keep it away from the possibility of it one day shorting out on something inside the board.

As long as you have a correctly wired C-Bus network, it doesnt matter where you connect it in, so yes, you could quite happily connect it to the nearest "switch" you have available. Just make sure that your network impedance/capacitance/cable length are up to scratch, and you should have no problems.

As far as an alternative to the plug-pack supplied with the CNI, there isnt any CIS-supplied power supplies that I know of, but as far as alternatives go, you could always use something like This from Jaycar Electronics, although you would need to modify the output lead on it, or if you wanted something DIN-rail mounted, you could try This, also from Jaycar.


Hope this helps you

Kindest Regards,
Darpa

 

Thanks

Thanks for your answers

 

I have been trying to work this out for ages.

I have two options

Power over ethernet. You can either make your own or buy something prefab. You can put the power supply near the ethernet switch and then power up the CNI anywhere you palce it on the [ethernet] network.

The other option which I stubmled across the other day is a din rail mount transformer.

While you might say there are plenty of these, try fit one in an enclosure that takes the CNI (and all other c-bus don rails), none will fit.
I stumbled across this from clipsal - a 4T16. its a din rail that will fit in nicely next to a MCB, CNI and thus should fit in a standard enclosure. Available in 12V as well. Clipsal list at $89 retail

I will be using the second option now

Mick

 

Power-Over-Ethernet

Hey guys,

For future reference,

If you want to use POE (Power Over Ethernet) to supply power to pretty much any device using nothing more than Cat5, Cat5e, or Cat6, then there is a very handy device made by D-Link, you can find it Here.

It will power both 5V and 12V devices, and I have used a few of these units before, and they work fairly well.

They will carry both power and Data at the same time through the one cable, so they would be ideal for mounting your CNI in a DIN-Rail enclosure for example, with other C-Bus equipment, and then to run a single length of Cat5/Cat5e/Cat6 back to your Ethernet networking equipment, and have the power supply for your CNI plugged in with your Ethernet equipment, instead of trying to use the plugpack supplied inside the DIN-Rail enclosure with the CNI.

A few words of caution though:
1. If your device uses more than 1 Amp of power, dont use POE. (a CNI only draws about 500mA, so it would be fine to use for this)
2. These types of units are for use with ETHERNET ONLY, dont EVER try to use any POE unit with C-Bus wiring!!
3. The limit on the length of Cat5 etc that you can run is 100m.


Hope this helps some of you

Darpa

P.S. Below is a link to an image of the basics of how POE works, where it says "Network Device" in the top-left corner, is basically where your CNI would be.

Click Here

 

A few minor (but important) points with the PoE topic.

The links you've shown are only for the so-called "mid-span" PoE.
"End-Span" have several (different) options which they may implement, and are significantly more complex in nature.

True "End-Span" PoE puts power down the *SAME PAIRS* that data go down, so the data and power are "mixed up together".

The "Mid-Span" offerings can be done in two ways.

The simple way basically sticks a power supply at one end, using the "spare" cable pairs (10-base-T only uses two pairs, Cat5/5e/6 cable has 4 pairs), and pulls power back off those spare pairs at the other end.

More complex midspan adaptors use a switchmode supply at the device end and inject a moderately high voltage at the power supply end (often up around 48-50 VDC). The switchmode supply can then deliver the appropriate voltage at the remote end, regulated and largely independant of the length of cable (and thus, resistance). The CURRENT the device takes can be well over the 1A you suggested (which is simplistic at best - the wire gauge, ambient temperature and cable length all need to be taken into account) but lets just say for a moment we're limited to 1A. 1A at 48V = 48W. That would be 4A at 12V or 8A at 6V (neglecting converter losses, so lets take off 20%). Thats still substantially more than 1A if it's needed.

I've been using this for years to power radiocommunications nodes, including amplifiers, routers, PTZ IP-cameras, weather stations etc) over existing ethernet cabling for years without significant problems, and over distances up to about 75 cable-metres. (One camera over 200 cable-metres worked fine as long as I didn't try to move it to quickly - the power required caused enough drop for the whole thing to lose regulation and require a reset to recover, but hey, that it worked at all was surprising).

RossW

 

Hey,

Just want to clear up what I said before, What I was talking about regarding the 1A limit was more to do specifically with the D-Link device I used as an example, as like you were speaking of Ross, the D-Link device also injects 48V into the cable, and converts it down to 12V or 5V at the other end. Also, the 100m cable-length limit I was referring to is more to do with the recommended max length with regards to the actual data side of things, more than the power supply side of it.
Also, the D-Link devices I describes above uses the typical 2 pairs for the Ethernet data, and the other 2 pairs for the power supply, this mean that using this device you would be limited to 10 BaseT (10Mbps) or 100 BaseT (100Mbps) Half-Duplex communication, as for Full-Duplex, or Gigabit ethernet, you require all 4 pairs for Data. But due to the low-bandwidth nature of C-Bus, and the fact that even under a "worst-case-scenario", the maximum data a CNI would ever route from C-Bus to Ethernet, and vice-versa uses a maximum of 24% of 10 BaseT's data-carrying capacity, I strongly doubt you would ever have a problem with the restrictions of the above D-Link device. I merely used that device as one cheap and simple example of the nature and advantages of POE.

You are quite right in everything you have said, and I apologise for not being more clear in the way I worded my previous post. Thankyou for the extra info Ross, its certainly something to think about for future installations

Kindest Regards,

Darpa

 

But you can break the power out again at the CNI and then feed it to the required terminals. This allows you to use the cat5 as the power cable as well.

Mick

 

Hey Nick,

We werent talking about feeding POE directly into the ethernet terminals of the CNI, we were talking about using a "breakout box" kind of device just before the CNI that splits the POE back into cat5 Data, and a seperate power outlet.

Feeding POE directly into an ethernet port on the CNI would NOT be a wise idea...

 

Just for everyones infomation. DLINK also have a new great device

http://www.dlink.com.au/Products.aspx?Sec=3&Sub1=12&Sub2=20&PID=118

This breakout box supports 802.1af midspan & endspan power.

If you have a switch that supports 802.1af you plug this on the end of the ethernet cable and get 12V or 5v at 1 amp . The beauty of this is you dont need a power injector. I have one running my CNI and works great.

The specs on the DLINK website are wrong. They say power supported on unused pins only. I have pointed this out to them and they are changing the specs. I have mine on a cisco 3750 POE switch (power over data pairs).

Charles