Beckhoff EPP3504-0023 Short Manual page 208

Mounting and wiring
◦ A defective contact surface can lead to random resistance values, depending on the contact
position and temperature. This makes reproducible measurements difficult.
• The effort for establishing the connection, including assembling the cables and connectors,
generally increases with increasing transmission quality requirements. This applies to the tools,
diligence and time required. Examples:
◦ Cage clamp/push-in connections (e.g. Beckhoff EL terminals), which are common in automation
applications, can be established or released in a few seconds with or without ferrule. A screwdriver
or push pin is sufficient. On the other hand, in many cases the (ohmic) repeatability is insufficient
for high-precision measurements in the SG/R range.
◦ Some 10 minutes and costs of some 10 euros should be assumed for assembly a lab-standard
LEMO/ODU connector (Beckhoff ELM3704-0001), depending on the number of poles. The result
is a top-quality connection system with a high number of permissible mating cycles.
◦ An intermediate solution can be field-configurable M8/M12 connections. For reasons of tightness,
they are more elaborate to assemble (soldering or insulation displacement contact, if necessary),
although the maximum number of mating cycles is similar to maintenance connectors.
• A pre-assembled connection should be subjected to electrical/mechanical testing before
commissioning: visual inspection, pull-out test, crimp height measurement, resistance measurement
etc.
208 Version: 1.2 EPP3504-0023