Automation Canada Machine Safety Issue May 2021 - 12

WHY USE " A LEVEL " SAFETY SOFTWARE?
A dedicated safety soſtware with third-party verified function blocks
helps to improve the readability of the program from one user to the
next.
* It reduces faults.
* It increases flexibility. Things like checkboxes, drop-down menus,
text boxes, and so on, make it much easier to interpret and manipulate
your program to do what you needed to do.
And to that point, I reference Section 8.1, IEC 62061, which says that the
soſtware shall:
* focus on the avoidance of faults
* produce readable, understandable, testable, maintainable, and
correct soſtware
*it is preferable to separate non-safety functions, such as basic
machine function, functionality, from safety-related control functions
Careful consideration has to be put into how you design your
application, your tools, to meet those needs. By using safety soſtware
level A, the bottom part of the V is removed. By using soſtware that's
been developed by a manufacturer, specifically for safety applications,
removes or shiſts the burden of module design, coding, and testing in
the view model from the user to the soſtware manufacturer. That means
simplicity and expediency.
For that reason, the rest of this article will only consider soſtware level
A type solutions, and some of the tools to look for in those solutions.
SOFTWARE TOOLS THAT MEET THE STANDARD REQUIREMENTS
Using the Wieland Electric soſtware as an example, here are tools that
can help achieve the compliance requirements of sections 8.1, 8.2, and
8.6 of the standard.
Verified Function Blocks
The use of third-party verified function blocks helps to achieve
CANADIAN AUTOMATION
VOLUME 3, ISSUE 3
12
compliance with Section 8.1 and 8.2 of IEC 62061 by providing
pre-verified logic and well-documented functions which can be
interpreted later by
another
person. A manufacturer
that
uses
third-party verified function blocks, can be confident that the logic in
there is sound and that it complies with the relevant safety standards.
To address Section 8.6 point 2, the values should be well defined and
limited. Here I will use an example of the Samos® Plan configuration of
analog input signals.
Aſter placing the current sensor in the project, parameters such as
connection type, sensor type, and limits can be set. The format is now
well defined. Dimensions can also be placed and the application can be
scaled
Automation Canada Machine Safety Issue May 2021

Table of Contents for the Digital Edition of Automation Canada Machine Safety Issue May 2021
