The 2-wire connection is not permissible for classes A and AA per DIN EN 60751 since here the internal lead resistance of the wires is added to the measured value. This will usually exceed the specified tolerance for the temperature sensor. A measurement of the cable resistance at room temperature and adjusting this in the transmitter (for example) is possible, but the temperature-dependent resistance of the inner conductor of the cable would still be added to the reading as an error.  Conclusion: A 2-wire circuit is not suitable for accurate temperature measurement.