Watlow CPC400 - Manual (Page 74)

Chapter 3: Operation and Setup CPC400 Series User’s Guide
60 Watlow Anafaze Doc. 0600-2900-2000
• Input signal high = 20 mA/20 mA = 1.0 = 100%
• For the Input range low and Input range high param-
eters, enter the process values that correspond to the
low and high signals. In this case, a 20 percent (4 mA)
signal represents 0.0 PSI. A 100 percent (20 mA) sig-
nal represents 50.0 PSI.
Table 3.4 Input Readings
Table 3.5 Scaling Values
Input Scaling Example: 0 to 5V О О О О (dc) Sensor
Situation
A flow sensor connected to the controller measures the flow
in a pipe. The sensor generates a 0 to 5V
Î (dc) signal. In-
dependent calibration measurements of the flow in the pipe
indicate that the sensor generates 0.5V at 3 gallons per
minute (GPM) and 4.75 V at 65 GPM. The calibration in-
strument is accurate ±1 GPM.
Setup
For the Disp format parameter in the Input menu, choose
-999 to 3000, because the calibrating instrument is precise
to ±1 GPM.
The tables below show the minimum and maximum input
signals and their corresponding process variables, and the
resulting values for the scaling parameters.
Process
Variable
Displayed
Sensor
Input
Reading in
Percent of Full Scale
50.0 PSI 20 mA 100%
.0 PSI 4 mA 100% x (4 mA/20 mA) = 20%
Parameter Value
Input range high 50.0 PSI
Input high signal 100.0%
Input range low .0 PSI
Input low signal 20.0%