rsdoran
Lifetime Supporting Member
I think with the last post concerning ATD I may have misstated or miscontrued what I did.
My machine is not using a PLC, therefore I did use a timer relay with 2 pushbuttons wired in series BUT both buttons have a set of N.O. contacts in series and a set of N.C contacts in series.
The logic behind this is if EITHER button is pushed opening one of the N.C. contacts it initiates the timer ckt. The second button must be pushed within .3 seconds to initiate the cycle.
To put this in ladder logic would be similar to what Rick Densing posted. His way is better I guess because you only need 1 set of contacts.
A QUESTION: When is it considered "needed" to use an ATD.
I know what OSHA (1910.217 pertains to a press) ANSI etc state.
When do you make the call to use an ATD? Is that an engineering call, safety, management or plain old CYA?
I am not asking about rules/regulations. What are the guidelines y'all use to determine when its appropriate is more what I would like to know.
My machine is not using a PLC, therefore I did use a timer relay with 2 pushbuttons wired in series BUT both buttons have a set of N.O. contacts in series and a set of N.C contacts in series.
The logic behind this is if EITHER button is pushed opening one of the N.C. contacts it initiates the timer ckt. The second button must be pushed within .3 seconds to initiate the cycle.
To put this in ladder logic would be similar to what Rick Densing posted. His way is better I guess because you only need 1 set of contacts.
A QUESTION: When is it considered "needed" to use an ATD.
I know what OSHA (1910.217 pertains to a press) ANSI etc state.
When do you make the call to use an ATD? Is that an engineering call, safety, management or plain old CYA?
I am not asking about rules/regulations. What are the guidelines y'all use to determine when its appropriate is more what I would like to know.