The PNOZsigma relaysÂ are multi-functional, have improved diagnostics, are easier to expand, and that benefit from improved switching capacity. Included in the line-up is what is believed to be the world's first 12.5mm wide safety relay.
This is the fourth generation of volt-free contact safety relays from Pilz and it incorporates a number of features that have been requested by customers around the world - including international approvals to make life easier for exporters. In addition, the range has been designed in such a way that a smaller number of relays perform the functions that previously required a much broader product range. For example, the 22.5mm-wide Category 4 PNOZ s5 safety relay monitors emergency stop switches, guard switches or light curtains - plus it benefits from an integrated timer function. This simplifies ordering and stockholding for machine builders, system integrators and maintenance departments.
Patented features within the PNOZsigma relays help to make the units more compact than ever before; typically the relays deliver the same functionality in 50 per cent of the space required previously, and it is now possible to install six safety outputs within a width of just 30mm. Despite their small physical size, the relays contain a microprocessor that delivers improved diagnostics via six LED indicators on the front panel. All safety relays in the range also now benefit from a semiconductor output for indication purposes.
For the models with user-selectable reset mode, operating mode and time functions, the configuration is now performed by means of switches on the front panel rather than by wired connections. The advantage of this is that the set-up is quicker, the chance of errors is reduced, and the tamper-proof technology is safer (if the switch position is altered, the relay will shut down the safety circuit - and it will remain shut down even if the switch is moved back to its original position). For extra protection, hinged covers over the switches can be secured in place using tamper-evident tags.
With traditional safety relays, adding an expansion module has required connections to be wired manually. However, the PNOZsigma relays feature a socket on the top that enables them to be connected to a neighbouring expansion unit by means of a jumper connector. Not only is this quicker and error-proof, but it also avoids the loss of a safety output that is the case when wiring a traditional safety relay to an expansion module.
All of the PNOZsigma safety relays can be ordered with either plug-in screw terminals or plug-in terminals with new spring-loaded terminal technology. Furthermore, the terminals have the same designations and are located in common positions on all models for ease of wiring and replacement.
The combination of jumper-connected expansion modules and spring-loaded cage clamp terminals can reduce wiring time by up to 20 per cent.
Other features of the PNOZsigma safety relays include a start-up facility for checking the correct functioning of light curtains and guard switches prior to a machine being enabled to start, and a maximum switching capability of 10A.