Setting the Analog Potentiometer Ranges
There are 4 analog potentiometers (pots) on the
face plate of the DL240 CPU. These pots can
be used to change timer constants, frequency of
pulse train output, value for an analog output
module, etc.
Each analog channel has corresponding V-
memory locations for setting lower and upper
limits for each analog channel.
To increase the value associated with the analog
pot, turn the pot clockwise. To decrease the
value, turn the pot counter clockwise
The table below shows the V-memory locations used for each analog channel. These are the
default location for the analog pots.
You can use the program logic to load the limits into these locations, or, you can use a
programming device to load the values. The range for each limit is 0 – 9999.
These analog pots have a resolution of 256 pieces.
Therefore, if the span between the upper and lower
limits is less than or equal to 256, then you have better
resolution or, more precise control.
Use the formula shown to determine the smallest
amount of change that can be detected.
For example, a range of 100 – 600 would result in a
resolution of 1.95. Therefore, the smallest increment
would be 1.95 units. (The actual result depends on
exactly how you’re using the values in the control
program).
DL205 User Manual, 4th Edition, Rev. B
3–19
Chapter 3: CPU Specifications and Operations
1
2
3
4
5
6
7
8
9
10
11
12
13
14
A
B
C
D
CH1
CH2
CH3
CH4
Analog Data
V3774
V3775
V3776
V3777
Analog Data Lower Limit
V7640
V7642
V7644
V7646
Analog Data Upper Limit
V7641
V7643
V7645
V7647
C
P
U
S
p
e
c
ifi
c
a
tio
n
s
Resolution = 256
H = high limit of the range
L = low limit of the range
H = 600
L = 100
Resolution =
H – L
256
Resolution = 500
256
Example Calculations:
Resolution = 1.95
600–100
ý
þ
ý
ý
230
2
4
0
2
5
0
-1
2
6
0
CH1
RUN
TERM
RUN
CPU
PWR
BATT
?
PORT 1
PORT 2
DL
240
CPU
Analog Pots
0
Max
CH1
CH2
CH2
CH3
CH4
Turn clockwise to increase value
