Automationdirect.com DirectLOGIC DL205 Series User Manual page 110

Setting the Analog Potentiometer Ranges
There are 4 analog potentiometers (pots) on the
230
face plate of the DL240 CPU. These pots can
240
be used to change timer constants, frequency of
250-1
pulse train output, value for an analog output
260 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.
Analog Data
Analog Data Lower Limit
Analog Data Upper Limit
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).
Turn clockwise to increase value
CH1
V3774
V7640
V7641
Chapter 3: CPU Specifications and Operations
Analog Pots
0
CH1
CH2
CH2
V3775 V3776
V7642 V7644
V7643 V7645
Resolution =
H = high limit of the range
L = low limit of the range
Example Calculations:
H = 600
L = 100
Resolution =
Resolution = 500
Resolution = 1.95
DL205 User Manual, 4th Edition, Rev. B
PWR RUN
BATT CPU
DL
240
RUN
CPU
TERM
CH1
CH2
CH3
CH4
? P ORT 1
PORT 2
Max
CH3 CH4
V3777
V7646
V7647
H – L
256
600–100
256
256
3–19
1
2
3
4
5
6
7
8
9
10
11
12
13
14
A
B
C
D