Safety monitoring device for monitoring safety-related states in a passenger conveyor system and method for operating same

A safety monitoring device for monitoring safety-related states in a passenger conveyor system comprising:

• a first double contact relay and a second double contact relay, each of the first and second double contact relays being controlled by a control voltage to switch a first normally open contact, a second normally open contact and a feedback contact synchronously between an open relay state and a closed relay state;
• a first controller and a second controller, each of the controllers determining properties of the passenger conveyor system correlated with a safety-related state of at least one component of the passenger conveyor system and generating the control voltages for controlling the first and the second double contact relays depending on the determined properties;
• wherein a first safety monitoring switch arrangement for monitoring a first safety-related state and for correspondingly switching a first switching state within a safety monitoring chain of the passenger conveyor system and a second safety monitoring switch arrangement for monitoring a second safety-related state and for correspondingly switching a second switching state within the safety monitoring chain of the passenger conveyor system are formed by the first and second double contact relays and the first and second controllers;
• wherein the first safety monitoring switch arrangement includes the first normally open contact of the first double contact relay connected in series with the first normally open contact of the second double contact relay;
• and
• wherein the second safety monitoring switch arrangement includes the second normally open contact of the first double contact relay connected in parallel with the second normally open contact of the second double contact relay.