New compact safety switch protects personnel

The company says that its new CTM transponder–coded safety switch with guard locking is designed for protection of the medium-weight guarding often used on manufacturing and automation equipment. This includes packaging lines, filling systems and component loaders for example. The switches feature high-level coding using transponder technology and a  diagnostic capability that provides what is described as “excellent resistance to misuse, especially where motivation for defeating the safety systems on the equipment is likely”. Information, such as number of operations and operating temperature can be used by the control system to ensure that the maximum ‘up-time’ of the equipment is maintained.

The new design means that additional holding magnets and clips are eliminated as the switch-actuator has a ‘holding’ force preventing the doors or flaps opening unintentionally while the equipment is in use and ‘unlocked’. The compact dimensions of the CTM switch, which is just 120x36x25mm, makes this one of the smallest yet strongest locking devices of its type says Euchner.

The locking ball actuator sits on an elastomer bearing to allow some degree of flexibility, and this enables the CTM to be used on smaller, lightweight doors with extremely small pivoting radii, down to 150mm. This allows lower cost swing-type doors and flaps to be used where more complex sliding access solutions may have been required previously. The CTM range of interlocks includes variants which are watertight and meet IP69. These use materials such as PEEK thermoplastics & 316L stainless steel fixings to ensure continued operation in arduous environments. They can be cleaned using high pressure without any detriment to the unit or actuator.

A feature which Euchner highlights is that owing to its small dimensions, the new CTM device can be fitted to units or doors that are close together.  Where most interlocks of this type require a distance of 100mm between each unit to avoid signal confusion, the CTM switches can be sited just 40mm apart. A bi-stable guard locking function with a locking force in excess of 1000N means that in the event of a power failure or shut-down, the switch remains in its previous state, making it safer for applications where body access is required or where clean-down or maintenance procedures are ideally carried out without power being applied to the machine. When the operating voltage of the switch is removed, the guard locking always remains in its current state. The guard door is either locked or it can be opened and closed as required.

For ease of operational monitoring, the new units feature two multi-colour LED displays that are visible from either side, allowing the current its status to be easily checked at a glance, even from a distance. The CTM’s interface allows multiple switches to be wired in series and still achieve high levels of safety-integrity up to Category 4/PLe. This series connection can also include a number of non-contact switches or other safety devices, with the added benefit of allowing continuous diagnostic monitoring of individual switches via the integration of Euchner’s ESM-CB unit. This  forwards diagnostic data to a higher-level control system via IO-Link. Using the diagnostic data, a users control system can easily be configured to send an alert if a switch is tampered with, if one is removed from a chain, or if an unauthorised change to the switch configuration is detected.