LOTO is very common in the industrial field, and the machine power source (electric, pneumatic, hydraulic, etc.) is isolated in a locked way by means of a mechanical lock to prevent the accidental start of the machine and equipment from causing injury to field personnel.

Why do I need a listing and a lock?

From the point of view of risk assessment, there is always a time for maintenance of machinery and equipment, and field staff need to enter the machine and equipment — dangerous areas for related operations. At this time, if the accidental start of the machine equipment occurs, it will cause harm to the operator, so the power source of the machine needs to be isolated (turned off) and locked.

From the perspective of laws, regulations and safety standards, there are also corresponding standards for LOTO on a global scale. In Section 4.1 of “ISO 14118 – Safety of Machinery – Prevention of Accidental start-up Standard” there is a similar description as follows – “Machines must provide a means of energy isolation and energy consumption, in particular when servicing, operation in the power loop and downtime”. Section 5.1 has a similar description – “The isolation device shall be able to be locked or otherwise securely isolated”.

The pain points of traditional locks

As we all know, the safety door is set up to facilitate the subsequent maintenance of the machine and equipment, and to facilitate the relevant personnel to enter and exit the machine. In order to prevent the machine from accidentally starting when the personnel are inside the machine, the relevant personnel will be required to hang their own mechanical safety lock on the safety door switch before entering the machine to ensure that no one else will close the door and restart the machine when they are inside the machine, because the safety door switch is monitored by the safety controller. There is no output from the safety controller when the door switch cannot be closed…

However, this kind of security obtained purely by “self-consciousness” has a lot of uncertainty in actual operation. Because the mechanical lock is generally more cumbersome, the padlock process is not convenient enough, and the personnel must enter and exit the machine from the same security door, many people forget the padlock, and even deliberately do not padlock with a lucky mind. If the equipment occupies a large area or there is a visual blind area inside the machine, then the personal non-padlock is very likely to lead to serious injuries and deaths.

eLOTO — The “Terminator” of the pain point of traditional listing locking scheme

PILZ’s eLOTO is an innovative electronic tag locking solution that includes a PITreader electronic key access reader, a security controller, and an authorities-certified “people check in check out” and “blind spot check” blocks.

As shown in the figure: Install the PITreader electronic key permission reader at the entrance of the security door or the PITgatebox security door operation button box containing the PITreader device for the check-in and check-out operation of personnel entering the security door.

The security controller in the scheme can generally choose the modular security controller PNOZmulti or the security PLC – PSS 4000. The security list will be established inside the controller, and the electronic key information of the check-in personnel will be saved in the security list. As long as there is any electronic key information of the personnel in the list, the machine equipment is not allowed to start.

When there is only one electronic key left in the security list, the blind spot check function is automatically activated, triggering the relevant indicator or buzzer to remind the “last person” to check the blind spot before signing out. When the person arrives at the blind spot inspection location, “press the blind spot Confirm” button, the blind spot inspection indicator is off, the buzzer is off, and then the person can sign out. Since the PitReaders in the field can be connected to the same security system, it is perfect to realize the freedom of personnel to check in and out from different security doors.