Watlow CLS - Manual (Page 125)

Linear Scaling Examples
CLS User’s Guide 117
Example 3
Situation
A pulse encoder which measures the movement of a conveyor is
connected to the CLS. The encoder generates 900 pulses for every inch
the conveyor moves. You want to measure conveyor speed in feet per
minute (f/m).
Setup
The encoder input is connected to the CLS' pulse input. An one second
sample time gives adequate resolution of the conveyor's speed.
The resolution is:
So a display format of -99.99 to +300.00 is appropriate.
The input readings are as follows.
At the maximum pulse rate of the CLS (2000 Hz):
At zero hertz, the input reading will be 0.00 f/m.
Therefore, the scaling values are:
Parameter Low Value High Value
Process Value (PV) 0 f/m 11.11 f/m
Input Reading (RDG) 0 Hz 2000 Hz
1 pulse
1 second
X
60 seconds
1 minute
X
1 inch
900 pulses
X
1 foot
12 inches
= 0.006 f/m
2000 pulses
1 second
X
60 seconds
1 minute
X
1 inch
900 pulses
X
1 foot
12 inches
= 11.11 f/m