RE: [CAD_CAM_EDM_DRO] Limit Switch Connectors

Hi,

Thanks to your repliers to my question.

I guessing my haste that I didn't make myself clear. I plan to solder the
wires directly to the limit switch itself. The connector was to plug the
wires from the switches into the controller box.

My preference is to have a separate connector per limit switch. maybe some
good quality 3.5mm mono plugs and panel mounted jacks are the answer?

Cheers, and thanks again.

Peter Homann
<mailto:peter.homann@...>
Work : +61 3 8530-7755
Adacel Technologies Ltd Fax : +61 3 9596-2960
250 Bay St, Brighton 3186, VIC, AUSTRALIA Mobile : 0421 601665
http://www.adacel.com.au Australian Software Engineering Excellence

> -----Original Message-----
> From: Stan Stocker [mailto:skstocker@...]
> Sent: Sunday, 5 May 2002 1:38 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] Limit Switch Connectors
>
>
> Hi Peter;
>
> There are many connector choices available, and RCA jacks may
> work, but
> they aren't a connector I ever selected for test fixtures. I'm not a
> CNC guy (yet), but designed quite a bit of factory test gear in the
> 80's.
>
> Several choices that come to mind include:
>
> DB style connectors. Easy to get in 9, 15, and 25 pin configurations,
> with 50+ pin versions aviailable. Easy to get hoods so your
> cables look
> good and provide strain relief. Available with crimp on
> insertable pins
> or fixed solder pot style. Screw jacks included, so you don't have to
> worry about things coming loose at embarrassing times. If you don't
> have to plug and unplug a lot, and only have to handle an Amp
> or two per
> pin, these are really quite good if you buy a good grade. As you get
> plenty of pins, you can keep shields, signal grounds, and signal lines
> sorted out to meet you needs. You can get a pretty good hole in a
> chassis for the chassis mounted connector via chain drilling and a bit
> of file work if you don't want to spend the money for DB
> series chassis
> punches - they aren't cheap new!
>
> BNC: More work to install on the cable, and require coax and
> connector
> body to match in size to be done right. Secure connections
> and easy to
> plug/unplug. The good BNC connectors require care to install
> correctly,
> see the ARRL handbook or some other book on RF construction
> for complete
> instructions. You only have one signal pin with standard BNC, so the
> shield and signal ground have to be joined at one end if you use a two
> conductor shielded cable rather than coax.
>
> Cannon style barrel connectors : Expensive, but a good way to get high
> pin density in a small package with a gasketed bayonet
> locking ferrule.
> Very strong and reliable connectors, used extensively on airborne
> electronics.
>
> Molex connectors: Sort of cheesy, the common style most
> folks have seen
> is the 4 pin connector used for floppy/hard disk power connections in
> PC. Cheap, easy to make up, chassis mount styles usually use springy
> nylon ears to lock the connector to the chassis that don't always hold
> securely.
>
> DIN connectors: As used on older PC keyboards, the 5 pin
> connector that
> is around 5/8 inch in diameter. Easy to get, not the
> greatest, but easy
> to wire and mount. Hoods tend to be a flexible plastic shell with a
> tight grommet that is just an extension of the hood. Mini styles as
> used on newer keyboards, or the similar S-VHS connector seem hard to
> find locally, I have no experience with them, as extension cables are
> cheap to buy made up.
>
> Jones plugs : The old (usually black) style connector often
> seen in OLD
> radio chassis for power supply connections. The male is a number of
> flat blades, the female chassis mount is a matching socket.
> Pretty good
> for semi-permanent setups, although the pins are tinned
> rather than gold
> plated. Most styles don't have jack screws, so connector
> body retention
> is provided by the electrical connectors themselves. Hoods are either
> supplied or available, so you can provide strain relief and a good
> looking installation. As said above though, the final strain
> relief is
> via connector holding force in most cases, rather than via
> the connector
> body.
>
> Point to Point soldering: Cheap, reliable if done with care
> to provide
> strain relief. A pain to deal with when you want to change something
> though!
>
> Crimp on individual lugs in male/female pairs, sometimes called barrel
> connectors or butt splice connectors. Easy to install, can be sealed
> with self vulcanizing tape or heat shrink. Easy to get at most auto
> parts stores in the electrical section. Try to find AMP or some other
> name brand, the "Made in one or more of the following countries..."
> parts vary from good to made of such poor materials that the metal
> cracks when crimped. You can find these in two pin connector styles,
> the ones I've seen are very much like a two pin molex style connector.
>
> You have probably figured out by now that RCA jacks come in low on my
> list. They have several defects, unless you purchase rather expensive
> examples. Poor dielectric materials in easy to find units, poor
> vibration resistance, open construction that makes contamination a
> problem, weak physical design, contacts loose their grip resulting in
> poor connections if plugged/unplugged repeatedly. The center
> conductor
> on the female socket doesn't provide a good gas tight self wiping
> connection in most versions as the gold "plate" (if any) is really a
> flash for show rather than the 35 to 50 microinch plating thickness
> needed for a gas tight self wiping contact interface. The nut that
> secures the female jack also grounds the outer shell to the chassis,
> mounting them on dielectric material to avoid this usually results in
> the connector loosening over time. Just barely OK in the intended
> application, and even then a common upgrade point in audio
> gear for good
> reason. There are exceptions, but be ready to spend 10 to 15 dollars
> per jack or socket to get good units, and that's if you luck into a
> deal. The 6 for $2 RCA connectors at the local chain "electronics"
> outlet are none too good. Really good ones are machined from solid
> stock (usually brass), with a 50 microinch gold plate over nickel (I
> think - it's been years), have teflon dielectric, well designed center
> contacts, and cost the earth! 15 years ago you could drop $35 or more
> per piece on male plugs. But they were really nice connectors!
>
> If you want a cheap and easy approach without much work, you
> can always
> use barrier strips. The twin screw style common these days (usually
> white plastic with all parts contained rather than the old screw
> terminal on bakelite style) allows you to mount the connector to the
> outside of the chassis, pass the wires from one side of the strip into
> the chassis through a grommet, and connect the outside world
> easily. I
> would add one or more cable clamps to the chassis and run
> your incoming
> cables through it/them to provide strain relief so thing don't get
> pulled loose should you snag a cable. Radio Shack even stocks these
> little gizmos, they aren't bad in the right situation.
>
> Binding posts are still around too.
>
> Another option might be 1/4 inch stereo or mono jacks as used on
> unbalanced microphones, headphones, and electric guitars. The stereo
> style will allow two signal lines and a ground. Avoid the
> really cheap
> jacks and plugs, they don't have good vibration resistance or strong
> retention of the plug. You could even use guitar patch cords to get
> color coded cables with the connector already installed on shielded
> cable. A good guitar or music store will have these, the ones Fender
> makes are quite good. Since I play a Strat I might be a tad biased on
> this :-) The jack on my guitar takes about 10 lbs of pull to
> disconnect. Some of the jacks have a switch mechanism built
> in, perhaps
> this could be wired to build in a failsafe, so if a limit switch isn't
> connected the unit won't run? This switch mechanism is what
> disconnects
> the speaker(s) when you plug in headphones on many amps. At least the
> jacks would be easy to mount, just drill a hole! I never used these on
> test equipment, but I've never had good examples come apart while
> playing. They used to be used for the test leads on many vacuum tube
> voltmeters (VTVMs), the predecessors to todays multimeter.
>
> Hope this helps,
> Stan
>
> Peter Homann wrote:
> >
> > Hi,
> >
> > I am after advice on what sort of connectors do people use
> to connect the
> > wires from limit switches to the controller unit.
> >
> > I am thinking of using RCA jacks. They are the ones used on
> a lot of audio
> > equipment.
> >
> > Any comments.
> >
> > Cheers,
> >
> > Peter Homann
> > <mailto:peter.homann@...>
> > Work : +61 3 8530-7755
> > Adacel Technologies Ltd Fax : +61
> 3 9596-2960
> > 250 Bay St, Brighton 3186, VIC, AUSTRALIA Mobile :
> 0421 601665
> > http://www.adacel.com.au Australian Software
> Engineering Excellence
> >
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