28
c
HAPTER
3:
Operation
F71/F41 Teslameter
3.5.4.4.1 Scaling
For corrected analog outputs, output voltage is scaled such that:
+100% of the current field range = +3.5 V
-100% of the current field range = -3.5 V
An example of this scaling is shown below:
A future software update will fully unlock scaling to allow users to set the range to
any two voltages between ±10V, aligning to any two field values.
The analog output is not calibrated. For applications that require high accuracy, correlate
the voltage directly to the front panel measurement value.
3.5.4.2 Raw Analog Output
Raw analog output is simply an amplified version of the Hall voltage delivered by the
Hall probe. Amplification occurs prior to demodulation or digitization, so it is the
most direct representation of the Hall voltage available. These modes are most valu-
able when viewing high frequency AC signals or magnetic pulses as the signal. View-
ing raw analog signals in DC or AC modes will result in a modulated signal that won't
be useful.
Due to the raw nature of this signal, the voltage level will not predictably relate to the
actual applied field. The best method for calculating the ratio between field and gen-
erated output voltage is to measure the voltage directly, and compare it to the peak
values that have gone through all the correction required for a more accurate field
value.
To help verify whether your calculations are likely to be correct, the following table
gives an approximate relationship between voltage and field:
The approximate relationships in the table are only valid over the flat frequency
response bands of both the teslameter and probe. Higher frequencies will appear to
have increased gain factors due to higher probe voltages as a result of inductive
pickup in the probe.
Conversion factor
Range
Tesla
Gaus
Range
35 T
100 mV/T
10 mV/kG
350 kG
3.5 T
1 V/T
100 mV/kG
35 kG
350 mT
10 mV/mT
1 V/kG
3.5 kG
35 mT
100 mV/mT
10 mV/G
350 G
TABLE 3-3
Scaling
Range
Approximate relationship
35 T
200 mV/T
3.5 T
2 V/T
350 mT
20 mV/mT
35 mT
200 mV/mT
TABLE 3-4
Raw analog output
