21.5 PRACTICE PROBLEMS
(Note: Problem solutions are available at http://sites.google.com/site/automatedmanufacturingsystems/)
1. Draw a timing diagram for the following FBD program.
2. Write a function block diagram program that will replace the following ladder logic.
3. Write a Function Block Diagram program to implement the following timing diagram. The sequence should begin when a variable `temp' rises above 80.
4. Develop a FBD for a system that will monitor a high temperature salt bath. The systems has
start and
stop buttons as normal. The temperature for the salt bath is available in
temp. If the bath is above 250 C then the
heater should be turned off. If the temperature is below 220 C then the
heater should be turned on. Once the system has been in the acceptable range for 10 minutes the system should shut off.
5. Write a function block diagram program that will replace the following ladder logic.
6. Write a structured text program that reads inputs from `channel 0'. An input string of `CLEAR' will clear a storage array. Up to 100 real values with the format `XXX.XX' will arrive on `channel 0' and are to be stored in the array. If the string `AVG' is received, the average of the array contents will be calculated and written out `Channel 0'.
