Conveyor slip detection and control

1. A conveyor for a mining system, the conveyor comprising:

a sprocket;

a torque limiting device including a first portion and a second portion, the first portion and the second portion rotatable with respect to one another when a torque limit of the torque limiting device is exceeded;

a drive mechanism coupled through the torque limiting device to the sprocket, the drive mechanism operable to drive the sprocket;

a first sensor operable to generate a first signal related to a position of the first portion of the torque limiting device;

a second sensor operable to generate a second signal related to a position of the second portion of the torque limiting device; and

a controller including a processor and a memory, the controller operable to

receive the first signal from the first sensor,

determine a first value for the position of the first portion of the torque limiting device based on the first signal,

receive the second signal from the second sensor,

determine a second value for the position of the second portion of the torque limiting device based on the second signal,

determine a difference between the first value for the position of the first portion of the torque limiting device and the second value for the position of the second portion of the torque limiting device,

determine an amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device based on the difference, and

generate a control signal to control an operation of the conveyor based on the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device.

2. The conveyor of claim 1 , wherein the first sensor and the second sensor are proximity sensors.

3. The conveyor of claim 1 , wherein the position of the first portion of the torque limiting device is an angular displacement of the first portion of the torque limiting device and the position of the second portion of the torque limiting device is an angular displacement of the second portion of the torque limiting device.

4. The conveyor of claim 1 , wherein the controller is further operable to compare the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device to a threshold value.

5. The conveyor of claim 4 , wherein the control signal is generated when the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device is greater than the threshold value.

6. The conveyor of claim 1 , wherein the control signal is operable to remove power from the drive mechanism.

7. The conveyor of claim 1 , wherein the control signal generates a visual indication of the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device.

8. The conveyor of claim 1 , further comprising a first target positioned on the first portion of the torque limiting device and associated with the first sensor, and a second target positioned on the second portion of the torque limiting device and associated with the second sensor.

9. The conveyor of claim 1 , wherein the conveyor is an armored face conveyor.

10. A method of controlling a conveyor for a mining system, the method comprising:

receiving a first signal from a first sensor related to a position of a first portion of a torque limiting device;

determining a first value for the position of the first portion of the torque limiting device based on the first signal;

receiving a second signal from a second sensor related to a position of a second portion of the torque limiting device;

determining a second value for the position of the second portion of the torque limiting device based on the second signal;

determining a difference between the first value for the position of the first portion of the torque limiting device and the second value for the position of the second portion of the torque limiting device;

determining an amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device based on the difference; and

generating a control signal to control an operation of the conveyor based on the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device.

11. The method of claim 10 , wherein the first sensor and the second sensor are proximity sensors.

12. The method of claim 10 , wherein the position of the first portion of the torque limiting device is an angular displacement of the first portion of the torque limiting device and the position of the second portion of the torque limiting device is an angular displacement of the second portion of the torque limiting device.

13. The method of claim 10 , further comprising comparing the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device to a threshold value.

14. The method of claim 13 , wherein the control signal is generated when the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device is greater than the threshold value.

15. The method of claim 10 , wherein the control signal is operable to remove power from a drive mechanism.

16. The method of claim 10 , wherein the control signal generates a visual indication of the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device.

17. The method of claim 10 , wherein the conveyor is an armored face conveyor.

18. A method of controlling a conveyor for a mining system, the method comprising:

determining a first value for a position of a first portion of a torque limiting device based on a first sensor signal;

determining a second value for a position of a second portion of the torque limiting device based on a second sensor signal;

determining an amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device based on a difference between the first value for the position of the first portion of the torque limiting device and the second value for the position of the second portion of the torque limiting device; and

generating a control signal to control an operation of the conveyor based on the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device.

19. The method of claim 18 , further comprising comparing the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device to a threshold value.

20. The method of claim 19 , wherein the control signal is generated when the amount of slip between the first portion of the torque limiting device and the second portion of the torque limiting device is greater than the threshold value.