Chapter 5, WEB CONTROL PANEL OPERATION
5-35
RATIO DAC Voltage
+7.5 7.5 V
+2.5 2.5 V
0 0.0 V
-2.5 -2.5 V
-7.5 -7.5 V
Log ratio
When set to Log ratio the corresponding DAC connector on the rear panel of the
instrument outputs a voltage related to the Log ratio calculation, which is defined
as follows:-
10
10 X output
LOG RATIO log
ADC1 input
where X output is the X channel output as a percentage of the full-scale
sensitivity and 1 is the voltage (expressed in volts) applied to the ADC 1 input
connector on the rear panel of the instrument. Hence, for example, if the
instrument were measuring a 100 mV signal when set to the 500 mV sensitivity
setting, the X1 channel output were maximized and a 1 V signal were applied to
the ADC1 input, then the value of Log ratio would be:-
10
0.1
10
0.5
LOG RATIO log
1.000
LOG RATIO = 0.301
The relationship between the voltage at the DAC connector and the Log ratio
value is defined as follows:-
Log ratio DAC Voltage
+2.000 2.000 V
0 0.0 V
-3.000 -3.000 V
Note: If Ratio < 0 then Log ratio = -3.000
Equation 1
When set to Equation 1 the corresponding DAC connector on the rear panel of
the instrument outputs a voltage related to Equation 1, which is defined using the
Output Equations panel, as follows:-
Equation 1 DAC Voltage
+10000 10.0 V
0 0.0 V
-10000 -10.0 V
Equation 2
When set to Equation 2 the corresponding DAC connector on the rear panel of
the instrument outputs a voltage related to Equation 2, which is defined using the
Output Equations panel, as follows:-