Watlow CLS200, Руководство пользователя

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CLS200 Series User’s Guide
Chapter 4: Setup
78
The scaling function is defined by two points on a conversion line. This line relates the process
variable (PV) to the input signal. The engineering units of the process variable can be any units—the
graph in
Figure 4.2 shows PSI as an example.
High Process
Variable
Low Process
Variable
Low
Reading
High
Reading
Input Reading
Figure 4.2 — Two Points Determine Process Variable Conversion
Before you enter the values determining the two points for the conversion line, you must choose
an appropriate display format. The controller has six characters available for process display; select
the setting with the desired number of decimal places. Use a display format that matches the range
of the process variable and resolution of the sensor. The display format you choose is used for the
process variable setpoint, alarms limits, deadband, spread and proportional band.
The process variable range for the scaled input is between the process variable values that
correspond to the 0% and 100% input readings. For the pulse input, it is between the 0Hz and
2000Hz readings. The process variable range defines the limits for the setpoint and alarms. See
Figure 4.3 .
High Process
Variabale
Process Variable
Low Process
Variabale
Low
Reading
High
Reading
Input Reading
Figure 4.3
— Process Variable Limited by Input Reading Range