An apparatus comprising: a first controller (104a, 104b, 202, 304, 306) configured to generate control signals for control of multiple Ethernet/Industrial Protocol, EtherNet/IP, compatible controlled field devices (210, 212, 362), the first controller comprising: first and second interfaces configured to: communicate with a controlled network comprising multiple EtherNet/IP-compatible input/output I/O, modules (206, 208, 360) and the multiple EtherNet/IP-compatible controlled field devices (210, 212, 362); and communicate over a first controller network (308, 310) and a second controller network (308, 310), each of the first and second interfaces is configured to communicably connect to at least one switch (204, 330, 332) that routes communications between the first controller and the controlled network; a third interface configured to communicate with a second controller; and at least one processing device configured to: detect a fault associated with the second controller while the second controller is in communication with at least one of the I/O modules and at least one of the controlled devices; upon detection of the fault associated with the second controller, resume the communication with the at least one I/O module and the at least one controlled device without the at least one I/O module updating the at least one controlled device to a failsafe condition; detect a fault associated with the first controller network while the first controller is in communication with the at least one I/O module and the at least one controlled device over the first controller network; and upon detection of the fault associated with the first controller network, switch the communication with the at least one I/O module and the at least one controlled device to the second controller network without the at least one I/O module updating the at least one controlled device to the failsafe condition. first and second interfaces configured to: communicate with a controlled network comprising multiple EtherNet/IP-compatible input/output I/O, modules (206, 208, 360) and the multiple EtherNet/IP-compatible controlled field devices (210, 212, 362); and communicate over a first controller network (308, 310) and a second controller network (308, 310), each of the first and second interfaces is configured to communicably connect to at least one switch (204, 330, 332) that routes communications between the first controller and the controlled network; communicate with a controlled network comprising multiple EtherNet/IP-compatible input/output I/O, modules (206, 208, 360) and the multiple EtherNet/IP-compatible controlled field devices (210, 212, 362); and communicate over a first controller network (308, 310) and a second controller network (308, 310), each of the first and second interfaces is configured to communicably connect to at least one switch (204, 330, 332) that routes communications between the first controller and the controlled network; a third interface configured to communicate with a second controller; and at least one processing device configured to: detect a fault associated with the second controller while the second controller is in communication with at least one of the I/O modules and at least one of the controlled devices; upon detection of the fault associated with the second controller, resume the communication with the at least one I/O module and the at least one controlled device without the at least one I/O module updating the at least one controlled device to a failsafe condition; detect a fault associated with the first controller network while the first controller is in communication with the at least one I/O module and the at least one controlled device over the first controller network; and upon detection of the fault associated with the first controller network, switch the communication with the at least one I/O module and the at least one controlled device to the second controller network without the at least one I/O module updating the at least one controlled device to the failsafe condition. detect a fault associated with the second controller while the second controller is in communication with at least one of the I/O modules and at least one of the controlled devices; upon detection of the fault associated with the second controller, resume the communication with the at least one I/O module and the at least one controlled device without the at least one I/O module updating the at least one controlled device to a failsafe condition; detect a fault associated with the first controller network while the first controller is in communication with the at least one I/O module and the at least one controlled device over the first controller network; and upon detection of the fault associated with the first controller network, switch the communication with the at least one I/O module and the at least one controlled device to the second controller network without the at least one I/O module updating the at least one controlled device to the failsafe condition.