Bad port?

[WLNKS]

AC250.PNG (30.8 KiB) Viewed 17673 times

I picked up two WS-8-250-ACs to try out. So far I have been using them as pretty much just a power supply while setting up equipment for installation. The POE options are really nice. I seem to have run into a problem though. I was powering a Siklu on port 1 (48V) and it lost power all of the sudden. Moved it to port 2, also set to 48V and it came back up no problem. Now port 1, with nothing plugged in shows 40Watts. Any ideas what went wrong?

[sirhc]

Does port 1 get an Ethernet link?

[WLNKS]

Yes, I should have mentioned. Everything seems fine except POE , 24V POE does not work either.

[sirhc]

Sending you an RMA Form

[lligetfa]

What is the pinout for Siklu PoE? 30W over 2 pairs is .625A of current. If it is one poly fuse per two pairs, it leaves little margin. That and if one of the power pairs gets flakey, the current on the ethernet transformer could double. Can they be powered using 48VH, spreading the current over more wires?

[Dave]

Yes, Les is correct, I was going to ask same thing...can you please tell us which radio model you are using?

[sirhc]

Yea, a poor crimp that does not get both wires from a pair can push the current over 1 single wire and double the load on the Ethernet transformer.

Now with a GB Ethernet device this is easy to spot as you will only get a 100M connection but if the devices is 10/100 you would not notice it but the Ethernet Transformer will likely die.

It is important to run the Ethernet Cable Diagnostics on the switch to insure cabling is correct before applying power.

A normal 10/100 passive POE device using pairs 3 and 4 for power will short pair 3 and 4 (NOT CROSS SHORT) meaning Blue and Blue/White are shorted for positive and Brown and Brown/White are shorted for negative, like a Legacy 10/100 UBNT airMAX radio.

So if say the Blue wire is crimped poorly and not in contact then the entire load is carried on the Blue/White wire and will burn out the Ethernet Transformer.

So a cable Diagnostic will show this if all is correct:
Pair 1 - OK or Abnormal Termination
Pair 2 - OK or Abnormal Termination
Pair 3 - Short
Pair 4 - Short

If you see this you have a bad crimp:
Pair 1 - OK or Abnormal Termination
Pair 2 - OK or Abnormal Termination
Pair 3 - Open <== Meaning one wire is not crimped correctly.
Pair 4 - Short

It is a good idea to experiement in a lab with the radios you use with known good cales that way you can use the cable diagnostic tool in the field easily to spot a problem.

[WLNKS]

Model 1200F and TL. Trying to find more information about the pinout. I thought it only used 4,5 and 7,8. Cables are all pre-made, maybe I just killed it mistakenly using 48V...

[petecarlson]

From Siklu re the 1200FX. Not 100% sure the TL is the same but I know they can use the same POE injector.

Two configurations are supported:

Alternative A+B
1 Vport Positive
2 Vport Positive
3 Vport Negative
4 Vport Positive
5 Vport Positive
6 Vport Negative
7 Vport Negative
8 Vport Negative

Alternative 2 A’+B
1 Vport Negative
2 Vport Negative
3 Vport Positive
4 Vport Positive
5 Vport Positive
6 Vport Positive
7 Vport Negative
8 Vport Negative

[WLNKS]

Thanks Pete. Sounds like I should have been using 48VH for the F at least.