valueType - Required. The data type of the value. Supported types are Bool, Int8 - Int64, Uint8 - Uint64, Float32, Float64, String, Binary, Object and arrays of the primitive types (ints, floats, bool). Arrays are specified as eg. Float32Array, BoolArray etc.
readWrite - R, RW, or W indicating whether the value is readable or writable.
units - indicate the units of the value, eg Amperes, degrees C, etc.
minimum - minimum value a SET command is allowed, out of range will result in error.
maximum - maximum value a SET command is allowed, out of range will result in error.
defaultValue - a value used for SET command which do not specify one.
assertion - a string value to which a reading (after processing) is compared. If the reading is not the same as the assertion value, the device's operating state will be set to disable. This can be useful for health checks.
base - a value to be raised to the power of the raw reading before it is returned.
scale - a factor by which to multiply a reading before it is returned.
offset - a value to be added to a reading before it is returned.
mask - a binary mask which will be applied to an integer reading.
shift - a number of bits by which an integer reading will be shifted right.