Switching On And Off; Using The Scu1 Controls; Offset Controls; Gain Controls - Bartington SCU1 Operation Manual

7.3. Switching ON and OFF

Caution: Connect the magnetometer before switching on the SCU1, as connecting a live
cable to the magnetometer may cause damage. Similarly, switch off the SCU1 before
disconnecting the magnetometer.
Caution: The SCU1 should be switched on and off using the IEC socket switch (Figure 1,
item 4) ("0" = OFF, "1" = ON).
Note: For best results, after switching ON, leave the SCU1 for 10 minutes for the internal
temperature to stabilise, before performing any measurements.

7.4. Using the SCU1 Controls

7.4.1. Offset Controls

The offset controls apply a DC offset value to the magnetometer output voltage, to generate a DC
adjusted signal voltage. This resulting voltage will be amplified by the gain controls, to form the
final SCU1 conditioned output signal.
The offset voltage range limits are -10 to +10V.
The offset control includes a coarse adjust, to set an approximate level, and a fine adjust to
achieve the exact offset level desired. A polarity switch selects whether the offset is added to or
subtracted from the magnetometer output, or set to OFF (zero offset).
Offset is generally used where an AC magnetic field being investigated is superimposed on a
background static (DC) field. The DC signal can be eliminated from the SCU1 conditioned output
by applying offset. The conditioned output will then contain only the AC signal, which can be
investigated at high resolution by using gain (amplification).
Example: to remove the background DC field from the X channel:
1. Set the X channel gain to 1, and the HPF to DC.
2. Set the X channel offset polarity switch to the centre position (no offset).
3. If the X channel meter shows a + reading, set the offset polarity to -; if meter shows -, set
offset polarity to +.
4. Adjust the offset controls until the meter reading decreases to zero.

7.4.2. Gain Controls

The gain controls apply amplification to the DC adjusted signals from the offset stage, to
generate the SCU1 conditioned analogue outputs.
BARTINGTON INSTRUMENTS
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