In our previous newsletter, we introduced you to the Inelco Tamper-proof a Pullkey System – a revolutionary new product that changes the safety game.
Let’s unpack the 6 obstacles designed to thwart tampering attempts.
#1 HIGH SAFETY AND INTEGRITY LEVEL
In the first place Inelco made sure that their Pullkeys have the highest possible Safety and Integrity Level Capability for a safety devise. Their BK400 / 500 Pullkey range has been assessed by an international third-party company to meet the relevant requirements of IEC 61508: 2010 Parts 1-2 and meets requirements providing a level of integrity to:
- Systematic Capability: SC 2 (SIL 2 Capable)
- Random Capability: Type A, Route 2H Device
- IEC 61508 Failure Rates in FIT*
- FIT = 1 failure / 109 hours
#2 PREVENT ENTRY TO THE PULLKEY
Our recommendation is to offer a sealed Pullkey that prevents a malicious intruder from getting access to the interior parts of the Pullkey which would prevent tampering, bypassing, or bridging of the safety system. This will be achieved by fitting tamper proof screws to the lid. Only special tools would be able to undo these screws. When a Pullkey is faulty the entire Pullkey needs to be replaced.
#3 FIT PLUGS TO ENSURE A QUICK CHANGE
For a sealed Pullkey, plugs need to be fitted so that the Pullkey can be changed in the event of a breakdown. It is crucial that these plugs are of the highest quality and standards. Plugs fitted to Pullkeys needs to have the following properties:
- Waterproof
- Dustproof
- Vibration resistant
- Locking mechanism that prevents it from pulling out from vibration
- End cap that could be fitted to the end of the plug to prevent water and dirt from getting to the connection pins
#4 SUPPLY A QUICK CHANGE PULLKEY BRACKET
A faulty Pullkey needs to be changed as soon as possible to keep loss of production to a minimum. To achieve this, Inelco developed a quick-change bracket that consists of a structure plate that is mounted to the conveyor structure. This plate is equipped with a drop lock pin at the bottom part. The Pullkey canopy is manufactured with a hook at the top rear end and this hook is hooked over the structure plate. The Pullkey canopy is then lowered over a single drop lock pin for quick attachment. A Pullkey can be changed in less than one minute.
#5 FIT A TAMPER SWITCH TO THE PULLKEY LID AS A BACKUP
A tamper switch is fitted inside the Pullkey, and if a malicious intruder managed to remove the tamper-proof screws of the lid, this switch would activate when the lid of the Pullkey is removed. The activation of this switch will trigger a relay at the drive, giving a tamper signal to the PLC. After a tamper signal, all Pullkeys need to be checked to make sure that they function correctly. When a Pullkey is changed and it is unplugged, a tamper signal will go through to the PLC, and the tamper flag can be cleared afterwards.
#6 RUN TWO INDIVIDUAL CIRCUITS TO THE DRIVE PLC
To accommodate budget constraints, it can offer five different systems which are all safe, however the more expensive options have more features.
The advantages and disadvantages are noted in a table below. For a plugged system the flexible Black Line Cable needs to be used since steel wire armoured cable is not suitable to accommodate their plugs.
