Safety System and Safety Controller

A safety controller comprising:

• a memory;
• a processor connected to the memory and configured execute a safety program;
• and
• an interface configured to connect the processor to a first communication unit and a second communication unit, wherein
• the first communication unit is configured to communicate data with one or more safety components via a first transmission line,
• the second communication unit is configured to communicate data with one or more safety components via a second transmission line,
• the second communication unit and the first communication unit are configured to independently of each other perform processing involved in communicating data, and
• the memory includes
• a first data area that holds data communicated by the first communication unit and a second data area that holds data communicated by the second communication unit which are arranged independently of each other, and
• a plurality of memory areas for the safety program executed by the processor to refer to, each memory area being associated with any predetermined one of the first and second data areas.