Condensation compensation in a motion control system
A motion control system has an enclosed assembly that encloses moving parts. A controller controls a motion of the moving parts and has an inhibit input that inhibits the motion. A sensor provides sensor outputs that depend on an assembly temperature and an assembly humidity in the enclosed assembly. A circuit provides a condensing condition output as a function of the sensor outputs. The condensing condition output couples to the inhibit input to inhibit the motion as a function of the sensor outputs.
1. A control system, comprising:
a controller controlling a motion of a head moving on a disc enclosed in an enclosed assembly, the controller having an inhibit input that inhibits the motion;
a sensor providing sensor outputs dependent on an assembly temperature and an assembly humidity in the enclosed assembly; and
a circuit providing a condensing condition output to the inhibit input as a function of the sensor outputs.
2. The control system of claim 1 wherein the sensor comprises a humidity transducer and a temperature transducer.
3. The control system of claim 2 wherein the humidity transducer has a temperature sensitivity and the circuit provides correction for the temperature sensitivity.
4. The control system of claim 2 wherein the humidity transducer has a humidity transducer temperature that is higher than the assembly temperature.
5. The control system of claim 1 wherein the condensing condition output turns on during an approach to a condensing condition.
6. The control system of claim 1 wherein the condensing condition output is on during a time interval after a condensing condition.
7. The control system of claim 1 wherein the enclosed assembly comprises a magnetic storage device.
8. The control system of claim 7 wherein the magnetic storage device comprises a hard disc drive.
9. The control system of claim 8 wherein the hard disc drive includes a head actuator and the motion of the head actuator is inhibited while the inhibit input is on.
10. The control system of claim 9 wherein the hard disc drive includes a spindle motor and the spindle motor is actuated while the inhibit input is on.
11. The control system of claim 9 wherein the disc drive includes a spindle motor and the spindle motor is inhibited while the inhibit input is on.
12. The control system of claim 9 further comprising a heater in the enclosed assembly, the heater being energized when the condensing condition output is on.
13. The control system of claim 1 wherein the enclosed assembly is sealed except for a filter.
14. A method of controlling motion, comprising:
controlling a motion of a head moving on a disc enclosed in an enclosed assembly;
providing an inhibit input to inhibit the motion;
providing sensor outputs dependent on an assembly temperature and an assembly humidity in the enclosed assembly; and
providing a condensing condition output to the inhibit input as a function of the sensor outputs.
15. The method of claim 14 wherein the sensor outputs comprises an output of a humidity transducer and an output of a temperature transducer, and the method further comprises:
correcting the output of the humidity transducer as a function of the output of the temperature transducer.
16. The method of claim 15 , further comprising:
heating the humidity transducer.
17. The method of claim 15 , further comprising:
heating the temperature transducer.
18. The method of claim 14 , further comprising:
turning on the condensing condition output during an approach to a condensing condition.
19. The method of claim 14 , further comprising:
turning on the condensing condition output during a time interval after a condensing condition.
20. The method of claim 14 wherein the enclosed assembly comprises a magnetic storage device.
21. The method of claim 20 wherein the magnetic storage device comprises a hard disc drive.
22. The method of claim 21 further comprising:
inhibiting motion of a head actuator in the hard disc drive while the inhibit input is on.
23. The method of claim 22 , further comprising:
actuating a spindle motor in the disc drive while the inhibit input is on.
24. The method of claim 22 , further comprising:
inhibiting a spindle motor while the inhibit input is on.
25. The method of claim 22 , further comprising:
energizing a heater in the enclosed assembly when the condensing condition output is on.
26. The method of claim 14 further comprising:
sealing the enclosed assembly except for a filter.
27. A control system, comprising:
a controller controlling a motion of a head moving on a disc enclosed in an enclosed assembly, the controller having an inhibit input that inhibits the motion;
a sensor providing sensor outputs dependent on an assembly temperature and an assembly humidity in the enclosed assembly; and
means for providing a condensing condition output to the inhibit input as a function of the sensor outputs.
28. The control system of claim 27 further comprising:
sealing the enclosed assembly except for a filter.
29. The control system of claim 27 wherein the enclosed assembly comprises a magnetic storage device.
30. The control system of claim 29 wherein the magnetic storage device comprises a hard disc drive.