An industrial control system comprising a control side and a field side, wherein the control side is electrically isolated from the field side, the industrial control system further comprising: first and second integrated circuit elements (34, 36) communicating first and second field signals (50, 52, 90, 91) on the field side, respectively, and first and second activity signals (54, 56), respectively, the first and second integrated circuit elements each including a watchdog timing circuit, wherein the first and second activity signals are heartbeat bits (30, 32); and first and second power shut-off components (60, 62) coupled with the first and second integrated circuit elements (34, 36) and configured to selectively switch between 1) providing power (68, 73) to the field side, and 2) removing power from the field side, wherein the watchdog timing circuit of the first integrated circuit element receives the second activity signal from the second integrated circuit element, and the watchdog timing circuit of the second integrated circuit element receives the first activity signal from the first integrated circuit element, and wherein the watchdog timing circuit of the first integrated circuit element is configured to cause the second power shut-off component to switch to removing power needed for generating the second field signal upon detecting an edge of the received second activity signal within a first pre-determined amount of time or upon failing to detect an second edge within a second pre-determined amount of time, wherein the watchdog timing circuit of the second integrated circuit element is configured to cause the first power shut-off component to switch to removing power needed for generating the first field signal upon detecting an edge of the received first activity signal within the first pre-determined amount of time or upon failing to detect an second edge within the second pre-determined amount of time, and wherein the watchdog timing circuits of the first and second integrated circuit elements are each configured to cause the second and first power shut-off components (60, 62), respectively, to switch to providing power for generating the second and first field signals, respectively, upon detecting at least three edges of the received activity signal (52, 54), such that the at least three edges are not detected within the first predetermined amount of time but detected within the second predetermined amount of time. first and second integrated circuit elements (34, 36) communicating first and second field signals (50, 52, 90, 91) on the field side, respectively, and first and second activity signals (54, 56), respectively, the first and second integrated circuit elements each including a watchdog timing circuit, wherein the first and second activity signals are heartbeat bits (30, 32); and first and second power shut-off components (60, 62) coupled with the first and second integrated circuit elements (34, 36) and configured to selectively switch between 1) providing power (68, 73) to the field side, and 2) removing power from the field side, wherein the watchdog timing circuit of the first integrated circuit element receives the second activity signal from the second integrated circuit element, and the watchdog timing circuit of the second integrated circuit element receives the first activity signal from the first integrated circuit element, and wherein the watchdog timing circuit of the first integrated circuit element is configured to cause the second power shut-off component to switch to removing power needed for generating the second field signal upon detecting an edge of the received second activity signal within a first pre-determined amount of time or upon failing to detect an second edge within a second pre-determined amount of time, wherein the watchdog timing circuit of the second integrated circuit element is configured to cause the first power shut-off component to switch to removing power needed for generating the first field signal upon detecting an edge of the received first activity signal within the first pre-determined amount of time or upon failing to detect an second edge within the second pre-determined amount of time, and wherein the watchdog timing circuits of the first and second integrated circuit elements are each configured to cause the second and first power shut-off components (60, 62), respectively, to switch to providing power for generating the second and first field signals, respectively, upon detecting at least three edges of the received activity signal (52, 54), such that the at least three edges are not detected within the first predetermined amount of time but detected within the second predetermined amount of time.