Engineering usually is an exercise in black or white, and ones or zeros. Read the instructions, apply to design, equal success.
Recently, We have been made aware that there are two interpretations (CAT \ PL) level when connecting a Pilz mo4p safety expansion relay output module to the dual-channel E-Stop input to a Fanuc robot controller.
We read the instructions for the mo4P, but they only indicate wiring examples to drive safety contactors, and subsequent back-check monitoring of the NC force guided contacts for contactor integrity check. There are no other wiring examples of interfacing to downstream safety equipment that needs dual-channel inputs.
We are interfacing the Pilz programmable PNOZ safety device to a Fanuc 6-axis robot.
We believe that the Fanuc controller has “equivalency” checking internally on its own dual-channel inputs for the e-stop.
But, here is the gray area of interpretation.
Possible installation A.
Pilz mo4p Output 0 wired to Fanuc ESS1
Pilz mo4p Output 1 wired to Fanuc ESS2
What CAT or PL level would this be?
Possible installation B.
Pilz mo4p Output 0 and Output 1 wired in series to Fanuc ESS1
Pilz mo4p Output 2 and Output 3 wired in series to Fanuc ESS2
What CAT or PL level would this be?
We are not trying to be lazy or take short-cuts. SAFETY is our absolute priority. However, economics are considered, and we do not want to waste double the amount of Pilz safety outputs, if the PL level of installation A meets our risk assessment PL criteria. Our problem is identifying the PL (cat) level of the two wiring strategies.
Thank you for your valued experience, and/or references to internationally recognized standards\directives publication specific article numbers.
Plastic
Recently, We have been made aware that there are two interpretations (CAT \ PL) level when connecting a Pilz mo4p safety expansion relay output module to the dual-channel E-Stop input to a Fanuc robot controller.
We read the instructions for the mo4P, but they only indicate wiring examples to drive safety contactors, and subsequent back-check monitoring of the NC force guided contacts for contactor integrity check. There are no other wiring examples of interfacing to downstream safety equipment that needs dual-channel inputs.
We are interfacing the Pilz programmable PNOZ safety device to a Fanuc 6-axis robot.
We believe that the Fanuc controller has “equivalency” checking internally on its own dual-channel inputs for the e-stop.
But, here is the gray area of interpretation.
Possible installation A.
Pilz mo4p Output 0 wired to Fanuc ESS1
Pilz mo4p Output 1 wired to Fanuc ESS2
What CAT or PL level would this be?
Possible installation B.
Pilz mo4p Output 0 and Output 1 wired in series to Fanuc ESS1
Pilz mo4p Output 2 and Output 3 wired in series to Fanuc ESS2
What CAT or PL level would this be?
We are not trying to be lazy or take short-cuts. SAFETY is our absolute priority. However, economics are considered, and we do not want to waste double the amount of Pilz safety outputs, if the PL level of installation A meets our risk assessment PL criteria. Our problem is identifying the PL (cat) level of the two wiring strategies.
Thank you for your valued experience, and/or references to internationally recognized standards\directives publication specific article numbers.
Plastic