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Safety relay is easily expandable solution

Edited by the Engineeringtalk editorial team Jul 4, 2005

A new monitoring safety relay provides an easily expandable solution where the requirement is to switch several safety circuits or different voltages from one E-stop.

Allen-Bradley Guardmaster's new MSR144RTP monitoring safety relay is a Category 4 device (per EN954-1) that provides an easily expandable solution where the requirement is to switch several safety circuits or different voltages from one E-stop.

Complemented by two types of plug-in expanders, the MSR144RTP eliminates time-consuming wiring and loss of safety contacts, while offering flexible and easy adaption to application specific requirements.

The versatile design of the MSR144RTP and its two types of expander units meets the demands of OEM machine builders for modular equipment that is simple to install; reduces installation costs, and offers a broad specification to cater for most types of applications.

The design overcomes a common problem faced by OEMs: the requirement to switch several safety circuits or different voltages with one E-stop command.

If the required numbers of safety contacts are not available on the safety relay itself, then expansion modules are required.

These have to be physically wired to be activated from the safety relay, and to facilitate monitoring within its feedback loop.

However, this is a costly and time-consuming procedure that also results in an overall loss of safety contacts.

The modular MSR144RTP takes the time, complexity and the cost out of this process.

It can be connected in four different input wiring configurations (one NC, two NC, two PNP connections from a light curtain, or a four wire safety mat) and is easily expanded - without additional wiring and without loss of safety contacts, simply by plugging-in the connector from the dedicated expansion modules.

The modules themselves are available in two types, and these can be used in any combination with the MSR144RTP up to a maximum of five.

The MSR230P module offers four additional (NO) safety contacts, whereas the MSR238DP, a time-delayed output expander, offers two NC safety and one NC auxiliary off delayed contacts to allow time delays up to 5min.

In addition to reducing installation costs and wiring complexity, the facility for simplified expansion provided by the modular MSR144RTP enables the unit to be configured more easily to meet specific user requirements.

Furthermore, the modular design helps to reduce the number of different inventory components that would normally be required.

Add to this the advantages of removable coded terminals and extended LED diagnostics, and the user is presented with a package that not only provides the highest levels of safety provision, but also the benefits of reduced service and maintenance costs.

The MSR144RTP conforms to standards EN954-1, ISO13849-1, IEC/EN60204-1, AS4024.1 and ISOTR12100, and is CE marked for all applicable directives: TUV and cULus.

The unit is encased in a tough, IP40 rated, polyamide PA 6.6 housing, which protects against shocks and vibration, and offers users convenient 35mm DIN rail mounting facilities.