Blowout preventer monitoring systems and methods

1. A monitoring system for a blowout preventer (BOP) of a mineral extraction system, comprising:

a sensor assembly, comprising:

a housing;

a rotatable wheel supported within the housing, wherein the rotatable wheel extends through an opening of the housing, such that the rotatable wheel is configured to contact a surface of a movable component of the BOP to enable linear movement of the movable component of the BOP to drive rotation of the rotatable wheel; and

an encoder configured to detect rotation of the rotatable wheel and to generate a signal indicative of the rotation of the rotatable wheel to enable determination of a position of the movable component of the BOP.

2. The system of claim 1 , wherein the rotatable wheel is supported by an axle comprising a magnet that is detectable by the encoder.

3. The system of claim 1 , wherein the encoder comprises one or more hall-effect sensors configured to detect a shift in a magnetic field induced by rotation of the rotatable wheel.

4. The system of claim 1 , wherein a radially-outer surface of the rotatable wheel is configured to contact the surface of the movable component of the BOP.

5. The system of claim 1 , wherein the rotatable wheel comprises a rubber material.

6. The system of claim 1 , wherein the housing comprises an elongated shaft portion and a cap portion coupled at a radially-inner end of the shaft portion, and the cap portion supports the rotatable wheel and the encoder.

7. The system of claim 6 , wherein the cap portion comprises a radially-inward facing recess that supports the rotatable wheel and enables the rotatable wheel to extend through the opening of the housing and a radially-outward facing recess open toward the elongated shaft portion that supports the encoder and enables the encoder to electrically connect to components of a controller assembly positioned within the elongated shaft portion via a cable.

8. The system of claim 1 , comprising one or more processors and an output device, wherein the one or more processors are configured to determine the position of the movable component of the BOP and to instruct the output device to provide an indication of the position of the movable component of the BOP.

9. The system of claim 1 , comprising a battery positioned within the housing and configured to provide a power supply to the encoder.

10. A blowout preventer (BOP) system for a mineral extraction system, comprising:

a movable component;

a body supporting the movable component; and

a sensor assembly comprising a housing, a rotatable wheel, and an encoder, wherein the rotatable wheel extends through an opening of the housing, such that the rotatable wheel is configured to contact a surface of the movable component to enable linear movement of the movable component to drive rotation of the rotatable wheel, and the encoder is configured to detect rotation of the rotatable wheel to enable determination of a position of the movable component.

11. The system of claim 10 , wherein the sensor assembly comprises a magnetic actuator that is non-rotatably coupled to the rotatable wheel, and the encoder is configured to detect a shift in a magnetic field of the magnetic actuator induced by rotation of the rotatable wheel.

12. The system of claim 11 , wherein the magnetic actuator comprises an axle that extends through a center of the rotatable wheel.

13. The system of claim 10 , wherein the sensor assembly is coupled to the body and is positioned on an open side of an actuator that is configured to drive a ram of the BOP.

14. The system of claim 10 , wherein the body comprises a bonnet that circumferentially surrounds a connector arm extending between a piston and a ram of the BOP.

15. The system of claim 10 , wherein the movable component comprises a connector arm extending between a piston and a ram of the BOP.

16. The system of claim 10 , comprising one or more processors and an output device, wherein the one or more processors are configured to determine the position of the movable component of the BOP based on a signal generated by the encoder and to instruct the output device to provide an indication of the position of the movable component of the BOP.

17. The system of claim 10 , comprising a control system configured to calibrate the encoder.

18. A method for monitoring a blowout preventer (BOP) of a mineral extraction system, the method comprising:

detecting, using an encoder, rotation of a rotatable wheel, wherein the rotatable wheel extends through an opening of a housing, such that the rotatable wheel is configured to contact a surface of a movable component of the BOP to enable rotation of the rotatable wheel to be caused by linear movement of the movable component of the BOP;

processing, using one or more processors, a signal generated by the encoder based on the detected rotation of the rotatable wheel to determine a position of the movable component of the BOP; and

instructing, using the one or more processors, a display to provide a displayed output indicative of the position of the movable component.

19. The method of claim 18 , wherein detecting rotation of the rotatable wheel using the encoder comprises detecting a shift in a magnetic field of a magnetic actuator that is coupled to the rotatable wheel as the rotatable wheel rotates.

20. The method of claim 18 , comprising calibrating the encoder using the one or more processors.