Safe camera systems

A safe camera system is electrosensitive protective equipment based on image processing and developed for safety-related applications. In contrast to conventional surveillance cameras, which are primarily used for observation, safe camera systems meet machinery safety requirements. They reliably record and analyse image data in order to monitor danger zones and, if necessary, send safety-related signals to the machine controller. In this way, they protect people from injury and ensure compliance with legal safety requirements.

Safe camera systems are used to safeguard danger points on plant and machinery. They monitor protection zones, open access points or complex 2D/3D zones and record detailed information across an entire monitored zone. A common area of application is to safeguard press brakes, for example.

Safe camera systems operate in accordance with the following principle:

1. Image recording: Optical sensors record the monitored zone.
2. Image processing: Safety-related algorithms analyse the data.
3. Object recognition: Distinguishes between human and material.
4. Signal transmission: In the event of danger, a safe shutdown signal is sent to the machine controller.

Strict standards and safety requirements apply to safe camera systems, for example:

• Machinery Directive 2006/42/EC – Essential health and safety requirements
• EN ISO 13849-1 – Performance level (PL) for safety-related control systems
• EN 61508 – Safety integrity level (SIL) for electrical/electronic systems
• DIN EN 954-1 – Categories for safety functions

As they always depict objects as the same size, regardless of the distance from the camera, telecentric camera systems are suitable for the safe monitoring of press brakes. They are installed on the upper die of the press brake and so travel with the upper tool.
 
By constantly synchronising data between the press brake's CNC controller, the safe controller and the mobile camera system, the safe controller reliably calculates the current position of the upper tool above the plate. Depending on the protected field range, even special-purpose presses such as tandem presses can be monitored.

The camera-based protection and measuring systems detect even the smallest foreign body in the protected field between the transmitter and receiver unit. The light beams are transmitted from the transmitter to the receiver via a telecentric lens, which is positioned on the opposite end of the press brake. The detection zones are installed in front of, behind and below the tool. This prevents anyone from intervening dangerously during press braking – from any side.

In addition to camera systems, optical sensors such as safety light curtains and laser scanners as well as radar-based sensors are mainly used to monitor danger zones. Find out more about how to use these sensors, and to distinguish between them:

Safeguarding danger zones with protective devices