dmx cable

[timpman19]

quick question from a new member

 

Just made up 2 lengths of DMX cable from a sample a friend gave me, one works fine the other doesn't. I've checked the connections and tested the cable to make sure there is no brakes in the wires. All seams to be ok but when put into a DMX circuit it doesn't work.

 

anyone have any suggestions?

[Brian]

I'm guessing that you tested continuity pin 1 to pin1, pin 2 to pin 2 etc. Did you check for any shorts between pins?

[Jamtastic3]

Yeah, you might want to carefully check the signal pins suggested by Brian. I came a cropper for an hr over a DMX connection circuit involving 12 scans. I couldn't understand why the link wasn't working between 5 of them. I eventually realised that the signal pins 2 and 3 had been reversed in that cable and so this cable was actually for the board to the first fixture. Some companies like Martin have different signal inputs to lighting board outputs (eg. Fat frog to Roboscan 812's in my case)

[bruce]

One of the best 30 quids I ever spent was on one of the Behringer cable testers. It has 3-pin XLR, jack, phono, din and possibly some others. No 5-pin XLR though.

 

Just plug in the cable and it immediately tells you via LEDs which input is connected to which output, and whether you have any short circuits. It also tells you whether the XLR shell is grounded.

 

It also has a "latch" function for detecting intermittent breaks - press the reset button, and wiggle the cables. If anything changes even momentarily - eg perhaps because of a poorly-soldered joint, or a short due to a stray strand, then the latching LEDs show a fault.

 

I tested a batch of cables of unknown origin, and found that about 10% were cross-wired, and others had bad connections.

 

Bruce.

[Modge]

second cable testers being a great investment (though ours doesn't do 5 pin DMX, but then seeing as we use a lot of martin lights most of our stuff is 3 pin any way and 3 -5 bodges as needed). Also they'd hardly complex to make your self - a box, some male and female connectors, a 9V battery, some LED's, a switch and bob's your uncle)

[johnhuson]

For testing 5-pin DMX Cables we have some of the Palmer Cable Tester which we have modified by removing the 5-pin DIN sockets, replacing them with cable glands and then have a short bit of cable coming out with 5-pin XLR's on the end.

 

The palmer testers are available from Adam Hall but are sadly quite a bit more money than the Behringer.

[timpman19]

thanks all

[Jonathan]

Or you could test it properly...

Artistic Licence DMX Tester

Come on guys!

[gareth]

Or you could test it properly...

Artistic Licence DMX Tester

Come on guys!

<{POST_SNAPBACK}>

Well, yes, Microscopes are wonderful pieces of kit (there's a thread elsewhere on this site to exactly that effect). But some people don't already own one and can't justify the £300+ cost of buying one, so have to rely on a bit of manual testing. And to that end, what exactly are you suggesting isn't "proper" about Brian's suggestion of doing a simple test for continuity and shorting? This kind of simple testing would pick up the problem in the majority of faulty cables.

[slim_mcslim]

on the line of cable testers...

 

terralec do one for £15 which wee's all over the behringer one from a vast height. not only is it half the price, it is really well built (for the money) but it tests XLR, phono, jack, speakon and din and also has banana sockets (is there a proper name for those?) to do continuity tests, I am so pleased that I never got round to buying the behringer version

 

Also they'd hardly complex to make your self - a box, some male and female connectors, a 9V battery, some LED's, a switch and bob's your uncle

 

but for £15 its not worth the hassle

 

paul...

[Andrew C]

on the line of cable testers...

 

terralec do one for £15 which wee's all over the behringer one from a vast height. not only is it half the price, it is really well built (for the money) but it tests XLR, phono, jack, speakon and din and also has banana sockets (is there a proper name for those?) to do continuity tests, I am so pleased that I never got round to buying the behringer version

 

Also they'd hardly complex to make your self - a box, some male and female connectors, a 9V battery, some LED's, a switch and bob's your uncle

 

but for £15 its not worth the hassle

 

paul...

<{POST_SNAPBACK}>

 

Banana = 4mm

 

Are those DINs 5 pin? If so, it would be dead easy to make a pair of jumpers for testing DMX cables.