Cabling and Connector Requirements

 To withstand the rigours of internal and external factory and works environments with elevated temperatures, humidity, oil and other chemicals plus rain and cleaning down with high pressure hoses requires a robust cable construction. Monitran’s standard cables use ETFE insulation for high temperature resistance and chemical inertness plus overbraiding with stainless steel mesh to protect against abrasion and wear.

The above cables are used up to 140ºC while perfluoroalkoxyethylene (PFA) insulation allows operation to 260ºC.

For long periods of immersion and operation down to 100m depth an external polyurethane coating over ETFE insulated cores with optional stainless steel overbraiding exhibits excellent water resistance and long life.

For lower temperature operation and less demanding environments like testing laboratories PVC insulated cables are acceptable and economical.

In the above examples the sensors are usually permanently mounted to machinery such that flexibility is not the most important criterion. However, for measurements with portable vibration analysers coiled, stretchable cable with PVC insulation offer convenience and economy.

The performance and reliability of results from vibration sensors depends critically on their electrical connection to the measuring system. Connectors and cables must be selected carefully to ensure optimum data collection, minimum signal interference and suitability for the working environment. Cables may be directly connected to the sensor or via a plug-in connector.

Factory environments demand cabling with high levels of noise rejection, protection from external electrical fields and radiofrequency interference. Where possible, cables will be twin-core shielded. The twin cores will be twisted together and carry the power/signal and return signals. However, where cable dimensions are too large to allow connection to small and miniature sensors then single core, screened (coaxial) cables are supplied.

Cables to constant current and 4-20mA output sensors can be extended over long distances with no significant effect on signal quality. When connecting large numbers of sensors to a remote control room it is convenient and economic to combine the cables at a junction box and make the onward connection with multi-core cables. Each sensor needs its own pair while a common shield is acceptable.

Charge output sensors, however, have very low level signals and 10m should be regarded as a normal maximum length. Following charge amplification, though, extension may proceed as above.

Again monitran accerelerometers  are normally supplied with a common 2 – pin military connector. ( MIL-C-5015 ). This is because it has been proofed to be a rugged ,simple and cost effective means of connectivity and is available with a variety of boots and sealing methods for different methods. However we can supply  connectors on the end of the cable to work with any electrical connector that your acquisition equipment uses. These include BNC and Microdot.

Construction

 Another important consideration is the type of coating the cable. You must be aware of the type of environment you plan to use the sensor in. The jacket material used can project from high and low temperatures, chemicals, radiation and moisture.

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