ConsoliDator Multi-Channel Controller
Instruction Manual
27
Exponent
Exponent mode refers to 2-point scaling with programmable exponent (programmable
root) extraction typically used in open-channel flow applications with weirs and flumes
to linearize the signal from a level transmitter and display the flow rate in engineering
units. The graph in
Figure 19
shows the display response based on example
parameters and exponent of “1.5”. For this mode select [Exponent] from
Function
options. To enter an exponent, select
Configure Function Parameters.
Press
EDIT
and
use arrow keys to change the value. Press
SAVE
when complete.
The exponent mode supports low-flow cutoff which can be used to suppress readings
below a programmed value. Below the cutoff value, the controller will display “0”. To
enter a cutoff value, select
Configure Function Parameters.
Press
EDIT
and use arrow
keys to change the value. Press
SAVE
when complete.
Follow
Sensor Input Setup
(page 29) to enter your scaling parameters.
Note: An input that goes below the
Low Value
parameter results in a display of “-999999”
indicating underrange condition. This can be prevented using the cutoff feature.
Process Scaling
Parameters Exponent
Input
(mA)
Display
(%)
High Value:
100.00
Low Value:
0.00
4.00 0.00
Sensor:
20.00
Sensor:
4.00
1.50000
5.00 1.56
6.00 4.42
7.00 8.12
8.00 12.50
9.00 17.47
10.00 22.96
11.00 28.94
12.00 35.36
13.00 42.19
14.00 49.41
15.00 57.00
16.00 64.95
17.00 73.24
18.00 81.85
19.00 90.77
20.00 100.00
Exponent Response
0.00
20.00
40.00
60.00
80.00
100.00
4.00
8.00
12.00
16.00
20.00
Sensor (mA)
Display (%)
Figure 19. Exponent Response Graph
