I am using a PNOZmulti to implement my safety tasks. We use a start button to start our automatic cycle. We use a "Travel to start position" button to prepare the machine for starting. Both buttons reset the safety devices on the machine (safety light curtain, ...) and then initiate movements once all the safety devices are active. My question: How can these buttons be read into the PNOZmulti:
1) Via safe inputs on the PNOZmulti?
2) Via non-safety-related inputs on the PNOZmulti?
3) Via inputs on the standard controller, followed by transfer to the PNOZmulti via a fieldbus module?
The buttons can be read in via the safe inputs on the PNOZmulti. However, this is not strictly necessary in most cases.
The plant's risk assessment will determine whether the buttons need a safety-related evaluation.
As the plant's hazardous movements are only executed if all the safety devices are active and are operating without error, in most cases the start or reset button can be read in via non-safety-related inputs on the PNOZmulti or on standard controller inputs.
Please note the following:
There must be a deliberate action when safeguards are reset or the plant is started.
As the start button and the "Travel to start position" button reset the safeguards and start the plant, the button must either be operated twice or an additional button must be installed, which resets the safeguards.
It's important that the danger zone must be visible from the position of the reset button, to ensure that there is nobody within the danger zone.