Automating Manufacturing Systems - Process Control and ...

plc analog - 22.24
writing it to an output card (O:001). If the value exceeds 100 then a BIG_LIGHT and SIREN
are turned on for 5sec. Use a structured design technique to develop ladder logic..
F
=
V
------ in
6
22.7 PRACTICE PROBLEM SOLUTIONS
1. b)
2.
R
10V – (–
10V)
= --------------------------------- = 200 7 bits = 128
0.1V
8 bits = 256
The minimum number of bits is 8.
3.
N = 12 R = 4096 V min
= – 10V V max
= 10V
V
V I
INT in
– V = ⎛----------------------------
min ⎞
⎝ – ⎠ R = 2608
V max
V min
V in
= 2.735V
V C
V I
= ⎛
⎝
----⎞ R ⎠
( Vmax – V min ) + V min = 2.734V
4. for the 1771-IFE card you would put keying in the back of the card, because voltage is being
measured, jumpers inside the card are already in the default position. Calibration might be
required, this can be done using jumper settings and suppling known voltages, then adjusting
trim potentiometers on the card. The card can then be installed in the rack - it is recommended
that they be as close to the CPU as possible. After the programming software is running the
card is added to the IO configuration, and automatic settings can be used - these change the
memory values to set values in integer memory.
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