Connector care

Medusa connectors are designed to be robust and suited for field applications. This applies both to the connectors on the cables and to the matching connectors mounted on the spectrometer or other equipment. That does not mean they need no care: a few basic habits keep them working reliably. For which cable uses which connector, see Cables and connectors.

General recommendations

• Keep connectors clean and dry.

• Brush or wipe off dirt around a connector before unmating it, so it cannot fall into the open connector or socket.

• Use a protective cap when a connector is unmated and the sensor/cable is placed in a dirty environment.

• Do not store a spectrometer for a long period with the cable still mated.

• Be careful with connector grease. Used incorrectly, dirt sticks to it and builds up inside the connector, which causes problems. The Birns Aquamate connectors are the exception, see below.

• Clean contacts with isopropyl alcohol (IPA). Avoid abrasive materials, the gold plating on most contacts is only a fraction of a micrometer thick.

• Inspect a connector before mating it and align it straight. Do not force a connection if it does not go together easily, or if you see bent pins, a cracked housing or corrosion.

• Grip the connector body, not the cable, when connecting or disconnecting.

• Give the cable some strain relief near the connector, for example a tie or clip a short distance back, so cable weight or movement does not load the connector joint itself.

• Avoid unnecessary connect and disconnect cycles where practical, each one wears the contacts a little and connectors have a rated mating cycle life.

Lemo push-pull

Align the red dot markers on the plug and socket, then push them together in a straight line until the latch clicks.

To disconnect, pull back the knurled release sleeve first, then withdraw the plug. Never disconnect by pulling on the cable or by twisting the connector body, both can damage the latch or strain the contacts inside.

Lemo M series ratchet coupling

This connector locks differently from the push-pull types: align it, then turn about three quarters of a turn until it locks. Reverse the turn to release it. If it does not turn smoothly, check the alignment rather than forcing it.

It is rated IP68, but only when mated or capped. Use a dust cap whenever the connector is unmated and used in a dirty environment, and treat the seal as unprotected without it.

Lumberg screw-lock

Tighten the coupling nut by hand until snug. Lumberg's own assembly instructions explicitly rule out lubricants, oils or greases on these connectors, and call for a clean, dust free environment when connecting or servicing them, since contamination in the threads shortens their working life.

M8/M12

Hand tighten the coupling nut until snug. Over torquing an M8/M12 connector can crack the insert or strip the threads, which breaks the seal it is meant to provide.

RJ-45, USB and DB-9

These carry data and, on some cables, power, but have no environmental seal to protect. Keep the latch tab on RJ-45 plugs intact and disconnect by releasing the tab rather than pulling the cable. Avoid sharp bends right at any of these connectors, that is where strain relief fails first.

SMA and TNC (GPS antennas)

Hand tighten only. See GPS Antennas for antenna and receiver details.

Birns Aquamate (underwater)

Birns Aquamate connectors need grease to seal properly, because they are used underwater.

• Before mating, fill the female contact holes with a small amount of silicone grease, such as Molykote 44 Medium.

• Wash the connector with fresh water and remove any grease, moisture or foreign particles before and after use, then dry it.