Subject: 440G-LZ Guard Locking Switch
The world of safety circuit design is constantly changing with new legislation and standards amending the way that we have previously implemented solutions to protect our operators and machines.
The latest brick generating waves in the safety pond, is a new standard ISO 14119 which focuses on the use of safety interlocks on guards. It offers a lot of recommendations on the design and use of guard interlocks and covers a lot of the newer technology products that are becoming available. One of the key points which is causing some issues, is the downgrading of safety levels when installing switches wired in series. Particularly if you have a door in the string that is opened once an hour, this can have a major effect on how you design your circuits in the future. The maximum that you can have to maintain a PLd circuit will be 5, any additional switches will reduce the circuit to PLc. If you have two frequently opened doors then the maximum achievable will be PLc. Previously there were no limits and these have been implemented to remove the issues of fault masking generating conditions where faults can lay undetected in the circuit.
So what can we do?
You could wire all of your switches back individually to a Safety PLC or modular relay system. Alternatively you could break your system into smaller sections by installing additional safety relays. All of these solutions would mean a radical change to the machine wiring and potentially much higher costs. The other alternative would be to fit a self-monitoring Ple rated switch that could be wired in a similar fashion to the existing circuit. There would be no limit to the number of switches and your circuit would be upgraded to the highest level Ple provided that the rest of the circuit was compliant.
We have had Sensaguard non-contact switches with this facility for some time, but we now have a Ple guard locking switch.
The 440G-LZ has a number of unique features which lend itself to all types of partial access guard design. Using RFID technology, it will not lock until the correct actuator is in place and its self-monitoring will turn off its outputs if any of the correct operating conditions are not met. It has a bi-stable solenoid which gives it a “Green” power consumption of 60% less than conventional switches. IP69K rated and ECOLAB certified and a high holding force for its size at 1300 newtons. Designed to be mounted on aluminium extrusions and available in power to release and power to lock versions……….
For once it is great to have a solution to your problem even before you know that you have one.
To view the product portfolio click here.
To purchase the product online click here.
For more information email info@routeco.com or call 0370 607 1000.
So what can we do?
You could wire all of your switches back individually to a Safety PLC or modular relay system. Alternatively you could break your system into smaller sections by installing additional safety relays. All of these solutions would mean a radical change to the machine wiring and potentially much higher costs. The other alternative would be to fit a self-monitoring Ple rated switch that could be wired in a similar fashion to the existing circuit. There would be no limit to the number of switches and your circuit would be upgraded to the highest level Ple provided that the rest of the circuit was compliant.
We have had Sensaguard non-contact switches with this facility for some time, but we now have a Ple guard locking switch.
The 440G-LZ has a number of unique features which lend itself to all types of partial access guard design. Using RFID technology, it will not lock until the correct actuator is in place and its self-monitoring will turn off its outputs if any of the correct operating conditions are not met. It has a bi-stable solenoid which gives it a “Green” power consumption of 60% less than conventional switches. IP69K rated and ECOLAB certified and a high holding force for its size at 1300 newtons. Designed to be mounted on aluminium extrusions and available in power to release and power to lock versions……….
For once it is great to have a solution to your problem even before you know that you have one.
To view the product portfolio click here.
To purchase the product online click here.
For more information email info@routeco.com or call 0370 607 1000.
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