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Configuration
14 DirectLine® DL421 Sensor Module User Manual 2/04
3. Configuration
3.1 Overview
Configuration Parameters
Set Up consists of configuring the following functions:
•
Buffer Group Selection – Only used with Auto Buffer Recognition calibrations.
Determines the set of standard pH buffer values to be used for Zero
(standardization) and Slope calibration by automatic buffer recognition. Each of
the available Buffer Groups is a set of 5 pH buffer standards that you can
select.
The available groups are: US
(default) , NIST, and EURO.
Table 3-1 Buffer Groups and the pH standard values
Buffer Group pH Buffers Display
US (default) 2 4 7 10 12 US
NIST 1.68 4.01 6.86 9.18 12.45 nISt
EURO
1 3 6 8 10
Euro
•
Solution Temperature Coefficient – Typically only used in power plants for
condensate/feedwater applications. Measured pH is displayed and transmitted
to a pH value normalized to what the pH value would be if the temperature of
the process was 25
°
C. Magnitude of normalization is dependent upon the
Solution Temperature coefficient, expressed in units of pH/10 °C with precision
to the hundredth decimal place.
The three available values are: 0.00
(standard setting, default) ,
−
0.16 pH/10 °C
(pure water) , and
−
0.32 pH/10
°
C (condensate/feedwater) .
•
Noise Suppression Frequency Selection – Selection of 50 Hz or 60 Hz.
Defaults to 60 Hz at unit reset.
•
Output Configuration – The following Output Configuration functions can be
selected:
0% Range 0 % Range values can be adjusted within a range
0.00 to 14.00 pH in 0.50 pH increments.
100% Range 100 % Range values can be adjusted within a range
0.00 to 14.00 pH in 0.50 pH increments.
0% Calibration Output current can be typically adjusted to within a
range of 3.80 mA to 4.40 mA.
100% Calibration Output current can be typically adjusted to within a
range of 19.60 mA to 20.40 mA.