Ametek 7124 Instruction Manual page 132

Chapter 5, FRONT PANEL OPERATION
5-78
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 RATIO would be:-

0.1

10

0.5
 
RATIO1
1.000



RATIO1 2
The relationship between the voltage at the DAC connector and the RATIO
value is defined as follows:-
RATIO1
+7.5
+2.5
0
-2.5
-7.5
LOG RATIO1
When set to LOG RATIO1 the corresponding DAC connector on the rear panel
of the main console outputs a voltage related to the LOG RATIO calculation,
which is defined as follows:-

LOG RATIO1 log
10
where X1 output is the X1 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 main console. 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:-

LOG RATIO1 log
10
LOG RATIO1 = 0.301
The relationship between the voltage at the DAC connector and the
LOG RATIO1 value is defined as follows:-
LOG RATIO1
+2.000
0
-3.000
Note: If RATIO1 < 0 then LOG RATIO1 = -3.000
EQUATION #1
When set to EQUATION #1 the corresponding DAC connector on the rear panel
of the main console outputs a voltage related to Equation 1, which is defined





DAC Voltage
7.5 V
2.5 V
0.0 V
-2.5 V
-7.5 V
  
10 X1 output
 
 
ADC1 input
 
0.1

10
 
0.5
 
 1.000 
 
DAC Voltage
2.000 V
0.0 V
-3.000 V