Page 268 - Programmable Logic Controllers, Fifth Edition - Mobile version

Ladder logic program
Inputs
Fill Outputs
L1 Stop Start Full solenoid L2
1
Fill
Start Fill solenoid
solenoid
Fill Filling
Filling
Stop solenoid Full Filling
2
Full
GEQ Full
I:012
3 GREATER THAN OR EQUAL
Source A I:012
Weight (All 16 bits) Alarm
transducer Source B 500
Full SUB
4 SUBTRACT
Source A I:012
Source B 500
Destination N7:1

Alarm
GEQ
5 GREATER THAN OR EQUAL
Source A N7:1
Source B 5
Figure 11-37 Program for Problem 2.

d. Assume that the vessel is filled to a weight of c. Assume that the set-point temperature is 600°F
510 lb. State the value of the number stored in and the thermocouple input module indicates a
each of the following words for this condition: temperature of 608°F. What is the status (energized
(1) I:012 or not energized) of each of the following outputs?
(2) N7:1 (1) PL1
e. With the vessel filled to a weight of 510 lb, state (2) PL2
the status of each of the logic rungs (true or (3) Heater
false). 4. With reference to the Celsius to Fahrenheit con-
3. Answer the following with reference to the tem- version program shown in Figure 11-39, state the
perature control program shown in Figure 11-38. value of the number stored in each of the following
a. Assume that the set-point temperature is 600°F. words for a thumbwheel setting of 035:
At what temperature will the electric heaters be a. I:012
turned on and off? b. N7:0
b. Assume that the set-point temperature is 600°F c. N7:1
and the thermocouple input module indicates a d. O:013
temperature of 590°F. What is the value of the
number stored in each of the following words at 5. Design a program that will add the values stored
this point? at N7:23 and N7:24 and store the result in N7:30
(1) I:012 whenever input A is true, and then, when input B is
(2) I:013 true, will copy the data from N7:30 to N7:31.
(3) N7:0 6. Design a program that will take the accumulated
(4) N7:1 value from TON timer T4:1 and display it on a
(5) N7:2 4-digit, BCD format set of LEDs. Use address

Math Instructions Chapter 11 249

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