Decentralised I/O modules connect safety components

Signals (and power) are transmitted on four twisted-pair cables without any fieldbus protocols, which keeps cabling costs low and avoids the need for additional fieldbus-compatible components, modules or end-of-line terminating resistors. The overall benefits of the PDP67 are claimed to be reduced installation time, cabling and, therefore, costs.

Pilz PDP67 modules feature M8 five-pin connections, which is also the case for many of the company's PSEN range of safety sensors, either in the form of a connector or on the end of the flying lead. M8 five-pin connectors provide for easy, quick and reliable connections, reduced installation costs, and simplified maintenance. Note that M8 eight-way connectors on PSEN sensors are available for conventional series wiring without using PDP67 modules, using T and Y junctions instead.

Module choice

Pilz is introducing two main versions of the PDP67, both of which are sealed to IP67. At a basic level a simple safety relay (such as the Pilz PNOZs4) can be used with a passive four-way PDP module to connect four independent input devices, which eliminates the need to use series wiring and permits the preservation of the highest EN ISO 13849-1 Performance Level, PLe, and SIL 3 of EN 62061 (IEC 62061). Note, however, that if contact-based sensors are used rather than electronic devices, the performance level for a corresponding interface will be assessed as PL c due to the lack of self-testing.

At a higher level, the eight-way modules realise even greater potential for on-machine expansion of I/O. The eight-way modules connect to Pilz PNOZmulti or PNOZmulti Mini software-configurable safety controllers via SafeLink expansion modules (PNOZml2p or PNOZmml2p) on the left-hand side of the controller base module - see above.

For connecting light grids and the PSENslock safety gate system, the 'high power' PDP67 F 8DI ION HP eight-way module features an additional supply voltage.

Safety zones

PDP67 modules can be cascaded to enable the number of I/O to be increased to a maximum of 64, and they are also a convenient way to implement safety zones on machines (see right).

Follow the link for more information about the PDP67 I/O modules.