BACKGROUND

The subject matter disclosed herein relates generally to industrial safety systems, and, for example, to emergency stop functionality.

BRIEF DESCRIPTION

The following presents a simplified summary in order to provide a basic understanding of some aspects described herein. This summary is not an extensive overview nor is intended to identify key/critical elements or to delineate the scope of the various aspects described herein. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

In one or more embodiments, a safety master device is provided, comprising a safety contactor configured to selectively connect and disconnect power from industrial equipment; a networking component configured to communicatively connect the safety master device to a network and exchange data with one or more other safety master devices over the network; a pulse verification component configured to receive a pulse signal via a single-wire safety channel and to determine whether the pulse signal conveys a defined pulse pattern; a relay control component configured to place the safety contactor in a connected state while the defined pulse pattern is identified on the pulse signal, and to place the safety contactor in a disconnected state in response to detecting a loss of the defined pulse pattern on the pulse signal; a message processing component configured to, in response to detecting the loss of the define pulse pattern on the pulse signal, send a diagnostic message directed to a safety input device on the single-wire safety channel that caused the loss of the defined pulse pattern; and a global e-stop component configured to, in response to determining that a response message received from the safety input device via the single-wire safety channel indicates that the safety input device is a global emergency stop device, instruct the one or more other safety master devices to place their respective safety contactors in their disconnected states.

Also, one or more embodiments provide a method for operating an industrial safety system, comprising monitoring, by a safety master device of a single-wire industrial safety circuit, a single-wire safety input terminal of the safety master device for presence of a pulse signal carrying a defined pulse pattern; in response to detecting, based on the monitoring, loss of the pulse signal: switching, by the safety master device, a safety contactor of the safety master device from a connected state to a disconnected state that disconnects power to one or more items of industrial equipment; and sending, by the safety master device via the single-wire safety input terminal, a diagnostic message directed to a safety input device on the single-wire safety circuit that caused the loss of the pulse signal; and in response to determining that a response message received from the safety input device via the single-wire safety input terminal identifies the safety input device as a global emergency stop device, instructing, by the safety master device, one or more other safety master devices networked to the safety master device to transition their respective safety contactors to their disconnected states.

Also, according to one or more embodiments, a non-transitory computer-readable medium is provided having stored thereon instructions that, in response to execution, cause a safety master device to perform operations, the operations comprising monitoring a single-wire safety input terminal of the safety master device for presence of a pulse pattern carried on a safety signal, wherein the single-wire safety input terminal connects the safety master device to a single-wire safety circuit; in response to detecting, based on the monitoring, loss of the pulse pattern: opening a safety contactor of the safety master device, wherein the safety contactor is configured to provide power to one or more items of industrial equipment while closed; and sending, via the single-wire safety input terminal, a diagnostic message directed to a safety input device on the single-wire safety circuit that is preventing the safety signal from proceeding to the single-wire safety input terminal; and in response to determining that a response message received from the safety input device via the single-wire safety input terminal identifies the safety input device as a global emergency stop device, sending a global emergency stop signal to one or more other safety master devices networked to the safety master device to open their respective safety contactors.

To the accomplishment of the foregoing and related ends, certain illustrative aspects are described herein in connection with the following description and the annexed drawings. These aspects are indicative of various ways which can be practiced, all of which are intended to be covered herein. Other advantages and novel features may become apparent from the following detailed description when considered in conjunction with the drawings.

