GBS Elektronik MCA-527 - Manual (Page 51)

Other and Auxiliary Measurements
5.2.2 Internal Temperature
The MCA527 has an on board temperature sensor to log the operation temperature of the
MCA. Main purpose of this is troubleshooting and quality control in case of remote
measurements. This internal temperature is shown in the diagnostics menu and it is
written in saved spectrum files. It is typically 9K higher than the environmental
temperature.
5.2.3 Detector Temperature
Detector temperature is an important parameter when using an NaI detector, as there the
signal amplitude depends significantly on temperature. The MCA527 supports two ways of
measuring temperature.
First is a digital temperature sensor with 1-wire interface, such as DS1822, connected to
pin 8 of the D-SUB9 preamplifier power supply connector. If such a sensor is found, its
temperature is displayed in the diagnostics menu and saved with the spectrum.
Second is a thermistor of 1k Ω nominal resistance at 25°C, connected to pin 5 of the
D-SUB9 connector. The resistance of this is sensed with a calibrated current of 0.5mA,
and from this the temperature is calculated.
5.2.4 Additional Analog Voltage
Pin 3 and Pin 5 of the D-SUB9 preamplifier power connector serve as slow auxiliary inputs
for still not defined purposes. The input impedance is 1M
Ω , the input voltage range is
0V...10V and the resolution is 11bit for every input. This voltages are displayed in the
diagnostics menu and are saved with a spectrum. Pin 5 additionally has the option of a
switchable 0.5mA calibrated current source and such can be used for measuring
resistances.
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