IFilterWheelV2Position Property |
Namespace: ASCOM.DeviceInterface
Exception | Condition |
---|---|
InvalidValueException | Must throw an InvalidValueException if an invalid position is set |
NotConnectedException | Must throw an exception if the Filter Wheel is not connected |
Must be implemented, must not throw a PropertyNotImplementedException.
Write a position number between 0 and N-1, where N is the number of filter slots (see Names). Starts filter wheel rotation immediately when written. Reading the property gives current slot number (if wheel stationary) or -1 if wheel is moving.Returning a position of -1 is mandatory while the filter wheel is in motion; valid slot numbers must not be reported back while the filter wheel is rotating past filter positions.
Note
Some filter wheels are built into the camera (one driver, two interfaces). Some cameras may not actually rotate the wheel until the exposure is triggered. In this case, the written value is available immediately as the read value, and -1 is never produced.