Field device switch monitoring

An industrial process control system comprising:

• a field device comprising:
• an active component selected from the group consisting of a sensor configured to sense a process parameter, and a control device configured to control a process of the industrial process;
• a switch electrically coupled to first and second terminals and configured to electrically connect the first and second terminals when in a closed state, and electrically disconnect the first and second terminals when in an open state;
• a switch monitor configured to generate a state output based on an electrical parameter of the switch, the state output being a first state output indicating the open state of the switch when the switch is in the open state, a second state output indicating the closed state of the switch when the switch is in the closed state, and a chattering state output indicating the closed state of the switch when the switch is in the closed state, the chattering state output comprising a signal that alternates between the first and second state outputs due to noise introduced into the switch monitor;
• an anti-chatter circuit of the switch monitor configured to output a chatter stabilized state output having a stabilized DC voltage based on the chattering state output indicating the closed state of the switch;
• and
• a controller configured to set the switch in one of the open and closed states, and generate a notification based on any one of the first state output, the second state output, and the chatter stabilized state output that indicates at least one of the current state of the switch and a condition of the switch;
• an external device electrically coupled to the switch through the first terminal;
• and
• a power supply electrically coupled to the switch through the second terminal and configured to power the external device through the switch;
• wherein power is supplied to the external device when the switch is in the closed state, and power is disconnected from the external device when the switch is in the open state.

A method of controlling an external device using an industrial process field device comprising:

• sensing a process parameter of an industrial process or controlling the industrial process using an active component of the field device;
• setting a switch of the field device to a current state corresponding to one of an open state, in which electrical power from an external power supply is disconnected from an external device, and a closed state, in which electrical power from the external power supply is connected to the external device, using a switch control signal generated by a controller of the field device;
• detecting an electrical parameter indicating the current state of the switch using a switch monitor of the field device;
• generating a state output indicating the current state based on the detected electrical parameter using the switch monitor, the state output being a first state output indicating the open state of the switch when the switch is in the open state, a second state output indicating the closed state of the switch when the switch is in the closed state, and a chattering state output indicating the closed state of the switch when the switch is in the closed state, the chattering state output comprising a signal that alternates between the first and second state outputs due to noise introduced into the detected electrical parameter;
• producing a chatter stabilized state output having a stabilized DC voltage based on the chattering state output indicating the closed state of the switch using an anti-chatter circuit of the switch monitor;
• and
• generating a notification based on any one of the first state output, the second state output, and the chatter stabilized state output that indicates at least one of the current state of the switch, a condition of the switch, and whether the state output aligns with an intended state of the switch corresponding to a switch setting, using the controller.