Rockwell Automation is launching the Guardmaster Safety Relay (GSR), which is the company's next-generation family of microprocessor-based safety relays that offers a number of benefits for machines that do not warrant the use of programmable safety controllers. In particular, the relays are designed so that one 22.5mm wide device performs the functions that would normally require two separate relays.
Another major advantage is the way the relays can be configured using a single rotary switch on the front; automatic and monitored manual resets can be configured this way, as can AND/OR logic. This means that the new family of six products covers applications that would otherwise require 50 or more conventional relays. More relays, with additional application-focused functions such as speed monitoring and light curtain muting, are currently in development.
A single-wire safety (SWS) connection feature means that a single wire can link multiple relays to expand the number of inputs and/or outputs without consuming I/O terminals. The combination of the SWS connection and rotary switch configuration means that more sophisticated safety-related control systems can be implemented, such as those with defined safety zones, global and local emergency stop switches and maintenance functions. All of this can be achieved while maintaining safety integrity at SIL 3 (or Performance Level e).
It should also be noted that Rockwell has installed universal inputs on the relays, meaning that each unit accepts signals from any safety device, including emergency stop switches, guard switches, safety light curtains and pressure-sensitive mats. All of the new relays are 24V DC devices, as this is by far the most commonly used supply voltage on machines today.
Customers requiring safety relay-based circuits that cannot be implemented using the functionality currently available within the GSR family are assured that the existing ranges of safety relays are not being discontinued, so these can be used for all or part of the safety circuits.
The six Guardmaster Safety Relays available at launch are:
- Safety relay with a single dual-channel input and two relay outputs
- Safety relay with a single dual-channel input and three relay outputs
- Safety relay with two dual-channel inputs and two solid-state outputs
- Safety relay with two dual-channel inputs and two relay outputs
- Safety relay output expansion module with four instantaneous relay outputs
- Safety relay output expansion module with four delayed relay outputs via an adjustable rotary switch
Rockwell Automation believes that around 70 per cent of the market for safety systems is not using programmable controllers - and these machine builders are therefore reliant on safety relays. Compared with using conventional relays, Rockwell says the GSR products can save 10 per cent on cost, 50 per cent on space and 30-50 per cent on installation and wiring time.
To help customers ensure that they have specified the relays correctly and the devices can be configured to operate as required, Rockwell has developed a Simulation Lab that an be downloaded for free from the company's Safety Solutions Portal. In addition, EPLAN macros are available. Follow the link to visit the Rockwell Automation Safety Solutions Portal and find out more about the new Guardmaster Safety Relays.