Which of the following is NOT on the Safety loop?

The selection related to the brake handle activation is indeed not part of the safety loop. The safety loop typically encompasses components and conditions that directly affect the operational safety and integrity of a system, particularly when it involves machinery or automation.

In this context, failures in couplers—whether they are permanent, semi-permanent, or electrical—represent critical elements that can compromise safety and must be monitored within the safety loop. These couplers act as connections between various system components, and their failure can lead to unsafe conditions or malfunctioning of the system.

Additionally, conditions like the MR (minimum rating) being below a specified pressure (600 kPa in this case) pertains to the system’s operational parameters, which also need to be maintained to ensure safe functioning.

On the other hand, the activation of a brake handle refers to a manual action that might not inherently be a part of the safety loop parameters. While brakes are undeniably essential for safety in any automated system, the act of activating a brake handle is a physical operator action rather than a monitored system parameter or failure mode that falls under the safety loop's definitions. Therefore, this aspect distinguishes it from the requisite components that the safety loop typically comprises.