Patent ID: 6549034
Filing Date: 2003-04-15
Classification: G05B

Abstract:
A programmable logic controller for safety applications comprising:a backplane; at least two I/O modules electrically connectable to the backplane; first and second control modules electrically connectable to the backplane; wherein the backplane, I/O modules and control modules include circuitry supporting a connected communications protocol in which failure of a connection between modules may be detected by the modules; wherein each of a given first and second control modules redundantly execute a control program to: (i) open connections over the backplane with the at least two I/O modules; (ii) receive over connections, redundant input signals from the I/O modules; (iii) generate a redundant output signal based on the received input signals; and (iv) transmit over a connection the redundant output signal to at least one I/O module.