In 2008, the Swedish Work Environment Authority tightened the control of machine safety in Swedish sawmills. This is due to many injuries in the industry. Just as many other sawmills in Sweden, Knäredssågen AB got a huge amount of work ahead. After much deliberation we decided to have a large master safety PLC for the entire facility.
We started with the most difficult - Trying to secure the entire timber intake including the driver of the wheel loader. After several positive signals from the Swedish Work Environment Authority, we continued with the rest. Many parts of the production were impossible to secure. In these cases, there were new machine instead.
After much consultation particular with Beijer Electronics (Johan Torstensson), Sick AB, Axelent (Daniel Axelsson) and all the employers we went beyond expectations. After a few years mostly was engaged, according to the same principle.
At present, we have 73 different protections in the system, such as light guards, doors, ropes and emergency stops connected. These protections break a total of 34 different safety zones.
The safety PLC that keeps track of everything is a Mitsubishi QS. To make it easier for the operators, all status is displayed via a Citect Scada system.