22
C. pH Linear Output
The analog output will produce a linear analog output if the user selects this option (see
figure 5). The analog output will be dependent on the pH_4 mA setting, pH_20 mA setting
and the current pH display.
pH antilog output
pH linear output
Figure 5
The pH linear analog output is based on the following equation:
mA
(pH)
= 4 mA + (16 mA) * (D
(pH)
- pH (4) ) / (pH (20) - pH (4))
Where:
mA
(pH)
= analog output
D
(pH)
= current pH display
pH(4)
= pH user setting for 4 mA
pH(20) = pH user setting for 20 mA.
[
Note:
The user can set the 4 mA and 20 mA OUT from 0.00 to 19.99 pH, but be reminded
that the range of pH is –2.00 to 16.00 pH.
The absolute difference of the 4 mA and 20 mA settings must be greater or equal to
0.10
pH
or else the analog output will be disabled.]
D. DO Linear Output
The analog output will produce a linear analog output if the user selects this option. The
analog output will be dependent on the DO 4 mA setting, DO 20 mA setting and the current
DO display.
