Intelligent lock control eliminates the human factor of uncertainty

The hazard potential "Human" in combination with simple lock control concepts poses a significant contamination risk. Intelligent configurable solutions facilitate compliance with purity classes in practice.

The most significant direct or indirect cause of particulate contamination in cleanrooms is well known to be the human itself. Whether employees perform unintended actions due to misinterpreted displays, someone loses patience in front of the locked lock gate and simply opens a door via emergency stop after a brief inspection, or hygiene measures are forgotten before entering the cleanroom. There are numerous ways in which procedures are not followed according to regulations, thus becoming sources of unnecessary contamination. Even simple lock control systems carry a considerable potential for danger, which is often overlooked at first glance. For example, a simple mutual locking cannot reliably prevent contamination, as during two or more consecutive lock-in procedures, it cannot be ensured that the room pressure conditions have been restored before reopening the doors. Additionally, repeated unnoticed use of the emergency stop function can pose an extra contamination risk.

Although not all human error sources can be eliminated with technology, at least in lock systems, some improvements can be achieved through an intelligent and well-thought-out control concept.

Pure hardware and PLC-based solutions versus configurable systems

While purely hardware-based lock controls, which offer a fixed, inflexible functionality for simple mutual locking, have been and are usually implemented customer-specifically using programmable logic controllers (PLCs). This allows for very complex and intelligent lock controls, but since in most cases both the number of locks to be controlled and the customer requirements vary, a new program must be written for each system or at least an existing program adapted, in other words: "reinventing the wheel". This involves significant effort – all functions must be tested again each time. Later modifications are also costly, as they can only be performed by the company that owns the source code.

Configurable solutions enable adaptation of a proven solution to customer requirements

Configurable lock controls include a multitude of ready-made and tested functions that can be activated or deactivated depending on the need for individual doors or lock systems.

This generally allows for much faster and more cost-effective project implementation, as no source code needs to be created and tested. Nevertheless, even the most unusual customer requests can be realized.

Furthermore, configurable lock controls offer the advantage that all functions can be configured via software instead of jumpers or plug-in modules. Any subsequent changes can be made very quickly via remote maintenance or even by the customer themselves. An on-site visit by the supplier is usually unnecessary. Since in fully configurable solutions the door panels are only connected via a bus system, both the implementation costs and the wiring effort are significantly reduced.

Doormate – a universal concept

Doormate is a flexible and fully modular lock control system. All door panels are connected in pairs via a bus system, minimizing wiring effort. Depending on the equipment of the door panels (operation buttons with integrated multi-color status indicator, emergency stop push button, time display, light buttons, access card reader, etc.) and the use of presence detectors in the lock systems, practically any functionality can be realized with the help of an easy-to-use configuration software. The entire configuration is performed using logical terms and timers and can be created with minimal IT knowledge. All statuses, such as door contacts, indicators, button and switch positions, etc., can be monitored in real-time during operation directly in the configuration software.

To avoid misinterpretations, particular emphasis was placed during the design of the door panels on a clear multi-color display with additional ring lighting for each lock status. Certain statuses are also signaled acoustically. Optionally, the panels can also be equipped with a digital display for visualizing the remaining waiting time and various error states.

A centrally implemented emergency stop acknowledgment function is fixed. An emergency stop state once triggered cannot be reset by unlocking the emergency stop push button but only at a central point, for example, via a key switch. This ensures that unauthorized and unintended use of emergency stop push buttons is always detected.

Forced room purge times after each door closing, provision of predictive control signals to "freeze" pressure regulation during an imminent door opening, as well as optical and acoustic alarms in case of errors, are essential features that should not be missing in any lock control system.

If desired, a discretion button can prevent further entry into the lock until it is released, or a direction priority can be implemented, e.g., favoring discharging over loading. Similarly, the door facing the higher cleanliness class can only be released after activating the disinfectant dispenser, which should help even the forgetful employee, or the lighting in the lock system can be time-controlled.

Overall, configurable lock control systems like the Doormate system represent a flexibility-oriented and, for larger lock systems, also economically superior alternative to conventional solutions.

Questions on this topic are gladly answered at Vision Pharma 2015, where Niotronic will be represented with its own booth (G2.3).